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Advanced Prostate Cancer

Radiotherapy in Prostate Cancer: Utilization in the Metastatic Setting

While external beam radiotherapy is a standard treatment option as first-line therapy for men with localized prostate cancer, it has been more recently recognized as an important component in the care of men with metastatic prostate cancer. This Center of Excellence article will explore recent evidence for the utilization of radiotherapy in the metastatic setting.

Written by: Christopher J.D. Wallis, MD PhD, Rashid Sayyid, MD MSc, & Zachary Klaassen, MD MSc
References:
  1. McAllister SS, Gifford AM, Greiner AL, et al. Systemic endocrine instigation of indolent tumor growth requires osteopontin. Cell. 2008;133:994-1005.
  2. Boeve LMS, Hulshof MCCM, Vis AN, et al. Effect on Survival of Androgen Deprivation Therapy Alone Compared to Androgen Deprivation Therapy Combined with Concurrent Radiation Therapy to the Prostate in Patients with Primary Bone Metastatic Prostate Cancer in a Prospective Randomised Clinical Trial: Data from the HORRAD Trial. Eur Urol. 2019;75(3):410-418.
  3. Parker CC, James ND, Brawley CD, et al. Radiotherapy to the primary tumour for newly diagnosed, metastatic prostate cancer (STAMPEDE): a randomised controlled phase 3 trial. Lancet. 2018;392(10162):2353-2366.
  4. Parker CC, James ND, Brawley CD, et al. Radiotherapy to the prostate for men with metastatic prostate cancer in the UK and Switzerland: Long-term results from the STAMPEDE randomised controlled trial. PLoS Medicine. 2022;19(6):e1003998.
  5. Ali A, Hoyle A, Haran AM, et al. Association of Bone Metastatic Burden With Survival Benefit From Prostate Radiotherapy in Patients With Newly Diagnosed Metastatic Prostate Cancer: A Secondary Analysis of a Randomized Clinical Trial. JAMA Oncol. 2021;7(4):555-563.
  6. Fizazi K, Tran N, Fein L, et al. Abiraterone plus Prednisone in Metastatic, Castration-Sensitive Prostate Cancer. New Engl J Med.. 2017;377(4):352-360.
  7. Hoyle AP, Ali A, James ND, et al. Abiraterone in “High-” and “Low-risk” Metastatic Hormone-sensitive Prostate Cancer. Eur Urol. 2018;76(6):719-728.
  8. Ost P, Reynders D, Decaestecker K, et al. Surveillance or metastasis-directed therapy for oligometastatic prostate cancer recurrence: A prospective, randomized, multicenter phase II trial. J Clin Oncol. 2018;36(5):446-453.
  9. Phillips R, Shi WY, Deek M, et al. Outcomes of Observation vs Stereotactic Ablative Radiation for Oligometastatic Prostate Cancer The ORIOLE Phase 2 Randomized Clinical Trial. JAMA Oncol. 2020;6(5):650-659.
  10. Deek MP, van der Eecken K, Sutera P, et al. Long-Term Outcomes and Genetic Predictors of Response to Metastasis-Directed Therapy Versus Observation in Oligometastatic Prostate Cancer: Analysis of STOMP and ORIOLE Trials. J Clin Oncol. 2022;JCO2200644.
  11. Palma DA, Olson R, Harrow S, et al. Stereotactic ablative radiotherapy versus standard of care palliative treatment in patients with oligometastatic cancers (SABR-COMET): a randomised, phase 2, open-label trial. Lancet. 2019;393(10185):2051-2058.
  12. Palma DA, Olson R, Harrow S, et al. Stereotactic Ablative Radiotherapy for the Comprehensive Treatment of Oligometastatic Cancers: Long-Term Results of the SABR-COMET Phase II Randomized Trial. J Clin Oncol. 2020;38(25):2830-2838.
  13. Supiot S, Vaugier L, Pasquier D, et al. OLIGOPELVIS GETUG P07, a Multicenter Phase II Trial of Combined High-dose Salvage Radiotherapy and Hormone Therapy in Oligorecurrent Pelvic Node Relapses in Prostate Cancer. Eur Urol. 2021;80(4):405-414.

The Impact of COVID-19 on Oncology Clinical Trials

Since the beginning of the COVID-19 pandemic in early 2020, the diagnosis, treatment and surveillance of cancer has been transformed globally. The heavy demand for resources, exacerbated by limited excess health system capacity, means that health care systems have become quickly overwhelmed and hospitals have become sources for virus transmission.

Written by: Zachary Klaassen, MD, MSc and Christopher J.D. Wallis, MD, PhD
References:

1. COVID, CDC, and Response Team. "Severe outcomes among patients with coronavirus disease 2019 (COVID-19)—United States, February 12–March 16, 2020." MMWR Morb Mortal Wkly Rep 69, no. 12 (2020): 343-346.
2. Thornton, Jacqui. "Clinical trials suspended in UK to prioritise covid-19 studies and free up staff." BMJ 368 (2020): m1172.
3. Majumdar, Sumit R., Matthew T. Roe, Eric D. Peterson, Anita Y. Chen, W. Brian Gibler, and Paul W. Armstrong. "Better outcomes for patients treated at hospitals that participate in clinical trials." Archives of internal medicine 168, no. 6 (2008): 657-662.
4. Skrutkowska, Myriam, and Charles Weijer. "Do patients with breast cancer participating in clinical trials receive better nursing care?." In Oncology nursing forum, vol. 24, no. 8, pp. 1411-1416. 1997.
5. McDermott, Mary M., and Anne B. Newman. "Preserving clinical trial integrity during the coronavirus pandemic." Jama (2020).
6. Marandino, Laura, Massimo Di Maio, Giuseppe Procopio, Saverio Cinieri, Giordano Domenico Beretta, and Andrea Necchi. "The Shifting Landscape of Genitourinary Oncology During the COVID-19 Pandemic and how Italian Oncologists Reacted: Results from a National Survey." European Urology (2020).
7. Wallis, Christopher JD, Giacomo Novara, Laura Marandino, Axel Bex, Ashish M. Kamat, R. Jeffrey Karnes, Todd M. Morgan et al. "Risks from Deferring Treatment for Genitourinary Cancers: A Collaborative Review to Aid Triage and Management During the COVID-19 Pandemic." European Urology (2020).
8. Segelov, Eva, Hans Prenen, Daphne Day, C. Raina Macintyre, Estelle Mei Jye Foo, Raghib Ali, Quanyi Wang et al. "Impact of the COVID-19 Epidemic on a Pan-Asian Academic Oncology Clinical Trial." JCO global oncology 6 (2020): 585.
9. Wang, Hongkai, Junlong Wu, Yu Wei, Yao Zhu, and Dingwei Ye. "Surgical Volume, Safety, Drug Administration, and Clinical Trials During COVID-19: Single-center Experience in Shanghai, China." European Urology (2020).
10. Waterhouse D, Harvey RD, Hurley P, Levit LA, Klepin HD. "Early Impact of COVID-19 on the Conduct of Oncology Clinical Trials and Long-term Opportunities for Transformation: Findings from an American Society of Clinical Oncology Survey." JCO Oncology Practice. 2020.
11. US Food and Drug Administration. "FDA guidance on conduct of clinical trials of medical products during COVID-19 pandemic: guidance for industry, investigators, and institutional review boards." (2020).
12. Tan, Aaron C., David M. Ashley, and Mustafa Khasraw. "Adapting to a pandemic-conducting oncology trials during the SARS-CoV-2 pandemic." Clinical Cancer Research (2020).
13. Khozin, Sean, and Andrea Coravos. "Decentralized Trials in the Age of Real-World Evidence and Inclusivity in Clinical Investigations." Clinical pharmacology and therapeutics 106, no. 1 (2019): 25-27.
14. Galsky, Matthew D., Mohamed Shahin, Rachel Jia, David R. Shaffer, Kiev Gimpel-Tetra, Che-Kai Tsao, Charles Baker et al. "Telemedicine-enabled clinical trial of metformin in patients with prostate cancer." JCO clinical cancer informatics 1 (2017): 1-10.
15. Borno, Hala T., and Eric J. Small. "Does the COVID-19 outbreak identify a broader need for an urgent transformation of cancer clinical trials research?." Contemporary Clinical Trials 92 (2020).
16. Duley, Lelia, Karen Antman, Joseph Arena, Alvaro Avezum, Mel Blumenthal, Jackie Bosch, Sue Chrolavicius et al. "Specific barriers to the conduct of randomized trials." Clinical Trials 5, no. 1 (2008): 40-48.
17. Uren, Shannon C., Mitchell B. Kirkman, Brad S. Dalton, and John R. Zalcberg. "Reducing clinical trial monitoring resource allocation and costs through remote access to electronic medical records." Journal of oncology practice 9, no. 1 (2013): e13-e16.

The Current Landscape of PSMA PET Imaging in Prostate Cancer: Advanced Prostate Cancer

While PSMA PET/CT is currently FDA approved for the initial staging of patients with presumed localized, high-risk prostate cancer and for the diagnostic work up of patients with biochemical failure following primary treatment, the role of PSMA PET/CT in patients with known metastatic prostate cancer is not as well-defined.
Written by: Christopher J.D. Wallis, MD PhD, Rashid Sayyid, MD MSc, & Zachary Klaassen, MD MSc
References:

 

  1. Deek MP, van der Eecken K, Sutera P, et al. Long-Term Outcomes and Genetic Predictors of Response to Metastasis-Directed Therapy Versus Observation in Oligometastatic Prostate Cancer: Analysis of STOMP and ORIOLE Trials. J Clin Oncol. 2022;JCO2200644.
  2. Philips R, Shi WY, Deek M, et al. Outcomes of Observation vs Stereotactic Ablative Radiation for Oligometastatic Prostate Cancer: The ORIOLE Phase 2 Randomized Clinical Trial. JAMA Oncol. 2020;6(5):650-9.
  3. Kneebone A, Hruby G, Ainsworth H, et al. Stereotactic Body Radiotherapy for Oligometastatic Prostate Cancer Detected via Prostate-specific Membrane Antigen Positron Emission Tomography. Eur Urol Oncol. 2018;1(6):531-7.
  4. Fizazi K, Shore N, Tammela TL, et al. Nonmetastatic, Castration-Resistant Prostate Cancer and Survival with Darolutamide. N Engl J Med. 2020;383:1040–9.
  5. Smith MR, Saad F, Chowdhury S, et al. Apalutamide and Overall Survival in Prostate Cancer. Eur Urol. 2021;79:150–8.
  6. Sternberg CN, Fizazi K, Saad F, et al. Enzalutamide and Survival in Nonmetastatic, Castration-Resistant Prostate Cancer. N Engl J Med. 2020;382:2197–206.
  7. Fendler WP, Weber M, Iravani A, et al. Prostate-Specific Membrane Antigen Ligand Positron Emission Tomography in Men with Nonmetastatic Castration-Resistant Prostate Cancer. Clin Cancer Res. 2019;25(24):7448-54.
  8. Wang B, Liu C, Wei Y, et al. A Prospective Trial of 68Ga-PSMA and 18F-FDG PET/CT in Nonmetastatic Prostate Cancer Patients with an Early PSA Progression During Castration. Clin Cancer Res. 2020;26(17):4551-8.
  9. Fourquet A, Aveline C, Cussenot O, et al. 68 Ga-PSMA-11 PET/CT in restaging castration-resistant nonmetastatic prostate cancer: detection rate, impact on patients' disease management and adequacy of impact. Sci Rep. 2020;10(1):2104.
  10. Wright GL, Grob BM, Haley C, et al. Upregulation of prostate-specific membrane antigen after androgen-deprivation therapy. Urology. 1996;48:326–34.
  11. Evans MJ, Smith-Jones PM, Wongvipat J, et al. Noninvasive measurement of androgen receptor signaling with a positron-emitting radiopharmaceutical that targets prostate-specific membrane antigen. Proc Natl Acad Sci USA. 2011;108:9578–82.
  12. Aggarwal R, Wei X, Kim W, et a. Heterogeneous Flare in Prostate-specific Membrane Antigen Positron Emission Tomography Tracer Uptake with Initiation of Androgen Pathway Blockade in Metastatic Prostate Cancer. Eur Urol Oncol. 2018;1(1):78-82.
  13. Emmett L, Yin C, Crumbaker M, et al. Rapid Modulation of PSMA Expression by Androgen Deprivation: Serial 68Ga-PSMA-11 PET in Men with Hormone-Sensitive and Castrate-Resistant Prostate Cancer Commencing Androgen Blockade. J Nucl Med. 2019;60:950-4.
  14. Ettala O, Malaspina S, Tuokkola T, et al. Prospective study on the effect of shortterm androgen deprivation therapy on PSMA uptake evaluated with 68Ga-PSMA-11 PET/MRI in men with treatment-naïve prostate cancer. Eur J Nucl Med Mol Imaging. 2020;47:665–673.
  15. Afshar-Oromieh A, Debus N, Uhrig M, et al. Impact of long-term androgen deprivation therapy on PSMA ligand PET/CT in patients with castration-sensitive prostate cancer. Eur J Nucl Med Mol Imaging. 2018;45:2045–2054.
  16. Seitz AK, Rauscher I, Haller B, et al. Preliminary results on response assessment using 68Ga-HBED-CC-PSMA PET/CT in patients with metastatic prostate cancer undergoing docetaxel chemotherapy. Eur J Nucl Med Mol Imaging 2018;45:602–12.
  17. Grubmüller B, Razul S, Baltzer P, et al. Response assessment using [68Ga]Ga-PSMA ligand PET in patients undergoing systemic therapy for metastatic castration-resistant prostate cancer. Prostate 2020;80:74–82.
  18. Kallur KG, Ramachandra PG, Rajkumar K, et al. Clinical utility of gallium-68 PSMA PET/CT scan for prostate cancer. Indian J Nucl Med 2017;32:110–7.
  19. Fanti S, Hadaschik B, Herrmann K. Proposal for Systemic-Therapy Response-Assessment Criteria at the Time of PSMA PET/CT Imaging: The PSMA PET Progression Criteria. J Nucl Med. 2020;61(5):678-82.

 

Androgen Receptor Signaling in Castration-Resistant Prostate Cancer

While androgen deprivation therapy (ADT) is nearly ubiquitously successful in suppressing testosterone to castrate levels with resultant declines in prostate-specific antigen (PSA) levels, the development of resistance is nearly as inevitable. While the natural history is variable, evidence suggests that most patients with advanced or metastatic prostate cancer will have disease progression within two to three years after initiation of androgen deprivation therapy, resulting in so-called “castration-resistant prostate cancer.”
Written by: Zachary Klaassen, MD, MSc and Christopher J.D. Wallis, MD, PhD
References: 1. Huggins, Charles, and Clarence V. Hodges. "Studies on prostatic cancer: I. The effect of castration, of estrogen and of androgen injection on serum phosphatases in metastatic carcinoma of the prostate." The Journal of urology 167, no. 2 Part 2 (2002): 948-951.
2. Coutinho, Isabel, Tanya K. Day, Wayne D. Tilley, and Luke A. Selth. "Androgen receptor signaling in castration-resistant prostate cancer: a lesson in persistence." Endocrine-related cancer 23, no. 12 (2016): T179-T197.
3. Visakorpi, Tapio, Eija Hyytinen, Pasi Koivisto, Minna Tanner, Riitta Keinänen, Christian Palmberg, Aarno Palotie, Teuvo Tammela, Jorma Isola, and Olli-P. Kallioniemi. "In vivo amplification of the androgen receptor gene and progression of human prostate cancer." Nature genetics 9, no. 4 (1995): 401-406.
4. Chen, Charlie D., Derek S. Welsbie, Chris Tran, Sung Hee Baek, Randy Chen, Robert Vessella, Michael G. Rosenfeld, and Charles L. Sawyers. "Molecular determinants of resistance to antiandrogen therapy." Nature medicine 10, no. 1 (2004): 33-39.
5. Wyatt, Alexander W., and Martin E. Gleave. "Targeting the adaptive molecular landscape of castration‐resistant prostate cancer." EMBO molecular medicine 7, no. 7 (2015): 878-894.
6. Robinson, Dan, Eliezer M. Van Allen, Yi-Mi Wu, Nikolaus Schultz, Robert J. Lonigro, Juan-Miguel Mosquera, Bruce Montgomery et al. "Integrative clinical genomics of advanced prostate cancer." Cell 161, no. 5 (2015): 1215-1228.
7. Grasso, Catherine S., Yi-Mi Wu, Dan R. Robinson, Xuhong Cao, Saravana M. Dhanasekaran, Amjad P. Khan, Michael J. Quist et al. "The mutational landscape of lethal castration-resistant prostate cancer." Nature 487, no. 7406 (2012): 239-243.
8. Cai, Changmeng, Housheng Hansen He, Sen Chen, Ilsa Coleman, Hongyun Wang, Zi Fang, Shaoyong Chen et al. "Androgen receptor gene expression in prostate cancer is directly suppressed by the androgen receptor through recruitment of lysine-specific demethylase 1." Cancer cell 20, no. 4 (2011): 457-471.
9. Antonarakis, Emmanuel S., Changxue Lu, Hao Wang, Brandon Luber, Mary Nakazawa, Jeffrey C. Roeser, Yan Chen et al. "AR-V7 and resistance to enzalutamide and abiraterone in prostate cancer." New England Journal of Medicine 371, no. 11 (2014): 1028-1038.
10. Chmelar, Renée, Grant Buchanan, Eleanor F. Need, Wayne Tilley, and Norman M. Greenberg. "Androgen receptor coregulators and their involvement in the development and progression of prostate cancer." International Journal of cancer 120, no. 4 (2007): 719-733.
11. Zoubeidi, Amina, Anousheh Zardan, Eliana Beraldi, Ladan Fazli, Richard Sowery, Paul Rennie, Colleen Nelson, and Martin Gleave. "Cooperative interactions between androgen receptor (AR) and heat-shock protein 27 facilitate AR transcriptional activity." Cancer research 67, no. 21 (2007): 10455-10465.
12. Gregory, Christopher W., Bin He, Raymond T. Johnson, O. Harris Ford, James L. Mohler, Frank S. French, and Elizabeth M. Wilson. "A mechanism for androgen receptor-mediated prostate cancer recurrence after androgen deprivation therapy." Cancer research 61, no. 11 (2001): 4315-4319.
13. Qin, Jun, Hui-Ju Lee, San-Pin Wu, Shih-Chieh Lin, Rainer B. Lanz, Chad J. Creighton, Francesco J. DeMayo, Sophia Y. Tsai, and Ming-Jer Tsai. "Androgen deprivation–induced NCoA2 promotes metastatic and castration-resistant prostate cancer." The Journal of clinical investigation 124, no. 11 (2014): 5013-5026.

The Current Landscape of Metastatic Castration-Resistant Prostate Cancer: Radioligand Therapy

Radiopharmaceuticals are pharmaceutical agents which contain radioisotopes that emit radiation, which may be used for diagnostic or treatment purposes. Historically, beta-particle emitting agents including strontium-89 (Metastron), samarium-153 (Quadramet), phosphorus-32, and rhenium-186 were used as palliative therapies for patients with symptomatic bone disease. In this context, they are quite effective in relieving bony pain but did not significantly improve survival.1-3
Written by: Rashid Sayyid, MD MSc, Zachary Klaassen, MD MSc & Christopher J.D. Wallis, MD PhD
References:
  1. Sartor O. Isotope Therapy for Castrate-Resistant Prostate Cancer: Unique Sequencing and Combinations. Cancer J 2016; 22(5):342-346.
  2. Ye X, Sun D, Lou C. Comparison of the efficacy of strontium-89 chloride in treating bone metastasis of lung, breast, and prostate cancers. J Cancer Res Ther 2018; 14(Supplement):S36-S40.
  3. James N, Pirrie S, Pope A, et al. TRAPEZE: a randomised controlled trial of the clinical effectiveness and cost-effectiveness of chemotherapy with zoledronic acid, strontium-89, or both, in men with bony metastatic castration-refractory prostate cancer. Health Technol Assess 2016; 20(53):1-288.
  4. Parker C, Nilsson S, Heinrich D, et al. Alpha emitter radium-223 and survival in metastatic prostate cancer. N Engl J Med. 2013;369(3):213-223.
  5. Chang SS. Overview of Prostate-Specific Membrane Antigen. Rev Urol. 2004;6(Suppl 10):S13-S18.
  6. Hofman MS, Violet J, Hicks RJ, et al. [177Lu]-PSMA-617 radionuclide treatment in patients with metastatic castration-resistant prostate cancer (LuPSMA trial): a single-centre, single-arm, phase 2 study. Lancet Oncol. 2018;19:825-833.
  7. Seifert R, Kessel K, Schlack K, Weckesser M, Bogemann M, Rahbar K. Radioligand therapy using [(177)Lu]Lu-PSMA-617 in mCRPC: a pre-VISION single-center analysis. Eur J Nucl Med Mol Imaging. 2020;47(9):2106-2112.
  8. Hofman MS, Emmett L, Sandhu S, et al. [177Lu]Lu-PSMA-617 versus cabazitaxel in patients with metastatic castration-resistant prostate cancer (TheraP): a randomised, open-label, phase 2 trial. Lancet. 2021;397(10276):797-804.
  9. Gaertner FC, Halabi K, Ahmadzadehfar H, et al. Uptake of PSMA-ligands in normal tissues is dependent on tumor load in patients with prostate cancer. Oncotarget. 2017;8(33):55094-55103.
  10. Sartor O, de Bono J, Chi KN, et al. Lutetium-177–PSMA-617 for Metastatic Castration-Resistant Prostate Cancer. N Engl J Med. 2021;385:1901-1103.
  11. Hartrampf PE, Seitz AK, Weinzierl F, et al. Baseline clinical characteristics predict overall survival in patients undergoing radioligand therapy with [ 177 Lu]Lu-PSMA I&T during long-term follow-up. Eur J Ncul Med Mol Imaging. 2022.

The Genetics of Prostate Cancer

Germline mutations in prostate cancer carcinogenesis

Some of the first data to delineate the value of assessment of inherited genetic changes in prostate cancer came from Pritchard and colleagues who assessed the prevalence of mutations in 20 DNA-repair genes among 692 patients with metastatic prostate cancer8. They identified such mutations in 82 men (11.8%).

Written by: Zachary Klaassen, MD, MSc
References: 1. Kang ZJ, Liu YF, Xu LZ, et al. The Philadelphia chromosome in leukemogenesis. Chin J Cancer 2016; 35:48.
2. An X, Tiwari AK, Sun Y, et al. BCR-ABL tyrosine kinase inhibitors in the treatment of Philadelphia chromosome positive chronic myeloid leukemia: a review. Leuk Res 2010; 34(10):1255-68.
3. Lichtenstein P, Holm NV, Verkasalo PK, et al. Environmental and heritable factors in the causation of cancer--analyses of cohorts of twins from Sweden, Denmark, and Finland. N Engl J Med 2000; 343(2):78-85.
4. Stanford JL, Ostrander EA. Familial prostate cancer. Epidemiol Rev 2001; 23(1):19-23.
5. Carter BS, Bova GS, Beaty TH, et al. Hereditary prostate cancer: epidemiologic and clinical features. J Urol 1993; 150(3):797-802.
6. Bostwick DG, Burke HB, Djakiew D, et al. Human prostate cancer risk factors. Cancer 2004; 101(10 Suppl):2371-490.
7. Alvarez-Cubero MJ, Saiz M, Martinez-Gonzalez LJ, et al. Genetic analysis of the principal genes related to prostate cancer: a review. Urol Oncol 2013; 31(8):1419-29.
8. Pritchard CC, Mateo J, Walsh MF, et al. Inherited DNA-Repair Gene Mutations in Men with Metastatic Prostate Cancer. N Engl J Med 2016; 375(5):443-53.
9. Castro E, Romero-Laorden N, Del Pozo A, et al. PROREPAIR-B: A Prospective Cohort Study of the Impact of Germline DNA Repair Mutations on the Outcomes of Patients With Metastatic Castration-Resistant Prostate Cancer. J Clin Oncol 2019; 37(6):490-503.
10. Nicolosi P, Ledet E, Yang S, et al. Prevalence of Germline Variants in Prostate Cancer and Implications for Current Genetic Testing Guidelines. JAMA Oncol 2019; 5(4):523-528.
11. Mateo J, Carreira S, Sandhu S, et al. DNA-Repair Defects and Olaparib in Metastatic Prostate Cancer. N Engl J Med 2015; 373(18):1697-708.
12. Robinson D, Van Allen EM, Wu YM, et al. Integrative clinical genomics of advanced prostate cancer. Cell 2015; 161(5):1215-1228.
13. Giri VN, Knudsen KE, Kelly WK, et al. Role of Genetic Testing for Inherited Prostate Cancer Risk: Philadelphia Prostate Cancer Consensus Conference 2017. J Clin Oncol 2018; 36(4):414-424.
14. Wallis CJ, Nam RK. Prostate Cancer Genetics: A Review. EJIFCC 2015; 26(2):79-91.
15. Ahmad AS, Vasiljevic N, Carter P, et al. A novel DNA methylation score accurately predicts death from prostate cancer in men with low to intermediate clinical risk factors. Oncotarget 2016; 7(44):71833-71840.
16. Majumdar S, Buckles E, Estrada J, et al. Aberrant DNA methylation and prostate cancer. Curr Genomics 2011; 12(7):486-505.

The Current Landscape of Metastatic Castration-Resistant Prostate Cancer: Immunotherapy and Targeted Therapies

While there have been clear survival benefits for patients with metastatic castration resistant prostate cancer (mCRPC) with the use of taxane chemotherapy and novel androgen receptor targeting agents, most patients eventually progress following these treatments. Thus, there remains a need for the development of novel therapeutic approaches. As summarized below, these have included immunotherapy and targeted therapies, which are discussed in this Center of Excellence mCRPC article.
Written by: Christopher J.D. Wallis, MD, PhD, Rashid Sayyid, MD, MSc, & Zachary Klaassen, MD, MSc
References:
  1. Kantoff PW, Higano CS, Shore ND, et al. Sipuleucel-T immunotherapy for castration-resistant prostate cancer. N Engl J Med. 2010;363(5):411-422.
  2. FDA grants accelerated approval to pembrolizumab for first tissue/site agnostic indication.  https://www.fda.gov/drugs/resources-information-approved-drugs/fda-grants-accelerated-approval-pembrolizumab-first-tissuesite-agnostic-indication. Accessed on Aug 6, 2022.
  3. Abida W, Cheng ML, Armenia J, et al. Analysis of the prevalence of microsatellite instability in prostate cancer and response to immune checkpoint blockade. JAMA Oncol. 2019;5(4):471-478.
  4. Pritchard CC, Morrissey C, Kumar A,et al. Complex MSH2and MSH6mutations in hypermutated microsatellite unstable advanced prostate cancer. Nat Commun. 2014;5:4988.
  5. National Comprehensive Cancer Network . Prostate Cancer (Version 4.2022).  https://www.nccn.org/professionals/physician_gls/pdf/prostate.pdf. Accessed Aug 6, 2022.
  6. Antonarakis ES, Piulats JM, Gross-Goupil M, et al. Pembrolizumab for Treatment-Refractory Metastatic Castration-Resistant Prostate Cancer: Multicohort, Open-Label Phase II KEYNOTE-199 Study. J Clin Oncol. 2020;38(5):395-405.
  7. Rubin MA, Maher CA, Chinnaiyan AM. Common gene rearrangements in prostate cancer. J Clin Oncol. 2011;29(27):3659-3668.
  8. Pritchard CC, Mateo J, Walsh MF, et al. Inherited DNA-Repair Gene Mutations in Men with Metastatic Prostate Cancer. N Engl J Med. 20116;375:443-453.
  9. Kunkel TA, Erie DA. DNA mismatch repair. Annu Rev Biochem. 2005;74:681-710.
  10. Abida W, Patnaik A, Campbell D, et al. Rucaparib in Men With Metastatic Castration-Resistant Prostate Cancer Harboring a BRCA1 or BRCA2 Gene Alteration. J Clin Oncol. 2020;38(32):3763-3772.
  11. Abida W, Campbell D, Patnaik A, et al. Non-BRCA DNA Damage Repair Gene Alterations and Response to the PARP Inhibitor Rucaparib in Metastatic Castration-Resistant Prostate Cancer: Analysis From the Phase II TRITON2 Study. Clin Cancer Res. 2020;26(11):2487-96.
  12. Hussain M, Mateo J, Fizazi K, et al. Survival with Olaparib in Metastatic Castration-Resistant Prostate Cancer. N Engl J Med. 2020;383:2345-57.
  13. de Bono J, Mateo J, Fizazi K, et al. Olaparib for Metastatic Castration-Resistant Prostate Cancer. N Engl J Med. 2020;382:2091-2102.
  14. Thiery-Vuillemin A, de Bono J, Hussain M, et al. Pain and health-related quality of life with olaparib versus physician's choice of next-generation hormonal drug in patients with metastatic castration-resistant prostate cancer with homologous recombination repair gene alterations (PROfound): an open-label, randomised, phase 3 trial. Lancet Oncol. 2022;23(3):393-405.
  15. de Bono JS, Mehra N, Scagliotti GV, et al. Talazoparib monotherapy in metastatic castration-resistant prostate cancer with DNA repair alterations (TALAPRO-1): an open-label, phase 2 trial Lancet Oncol. 2021;22(9):1250-1264.
  16. Gasmi A, Roubaud G, Dariane C, et al. Overview of the Development and Use of Akt Inhibitors in Prostate Cancer. J Clin Med. 2022;11(1):160.
  17. De Bono JS, De Giorgi U, Rodrigues DN, et al. Randomized Phase II Study Evaluating Akt Blockade with Ipatasertib, in Combination with Abiraterone, in Patients with Metastatic Prostate Cancer with and without PTEN Loss. Clin Cancer Res. 2019;25:928–936.
  18. Sweeney C, Bracarda S Sternberg CN, et al. Ipatasertib plus abiraterone and prednisolone in metastatic castration-resistant prostate cancer (IPATential150): a multicentre, randomised, double-blind, phase 3 trial. Lancet. 2021;398(10295):131-142.
  19. Crabb SJ, Griffiths G, Marwood E, et al. Pan-AKT Inhibitor Capivasertib With Docetaxel and Prednisolone in Metastatic Castration-Resistant Prostate Cancer: A Randomized, Placebo-Controlled

Oligometastatic Prostate Cancer – Treatment of the Primary Tumor and Metastasis Directed Therapy

In 2018 1.3 million prostate cancer (PCa) cases were diagnosed worldwide, with approximately 20% having metastatic disease.1 Oligometastatic PCa is defined as a state of low-volume metastatic disease that appears to be prognostically different and likely amenable to different treatment options, which could potentially change the disease trajectory when compared with high-volume metastatic disease.2 
Written by: Hanan Goldberg, MD
References: 1. Bray F, Ferlay J, Soerjomataram I, Siegel RL, Torre LA, Jemal A. Global cancer statistics 2018: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries. CA: a cancer journal for clinicians 2018; 68(6): 394-424.
2. Hellman S, Weichselbaum RR. Oligometastases. Journal of clinical oncology : official journal of the American Society of Clinical Oncology 1995; 13(1): 8-10.
3. Weichselbaum RR, Hellman S. Oligometastases revisited. Nature reviews Clinical oncology 2011; 8(6): 378-82.
4. Soloway MS, Hardeman SW, Hickey D, et al. Stratification of patients with metastatic prostate cancer based on extent of disease on initial bone scan. Cancer 1988; 61(1): 195-202.
5. Weiner AB, Nettey OS, Morgans AK. Management of Metastatic Hormone-Sensitive Prostate Cancer (mHSPC): an Evolving Treatment Paradigm. Current treatment options in oncology 2019; 20(9): 69.
6. Rao A, Vapiwala N, Schaeffer EM, Ryan CJ. Oligometastatic Prostate Cancer: A Shrinking Subset or an Opportunity for Cure? American Society of Clinical Oncology educational book American Society of Clinical Oncology Annual Meeting 2019; 39: 309-20.
7. Tosoian JJ, Gorin MA, Ross AE, Pienta KJ, Tran PT, Schaeffer EM. Oligometastatic prostate cancer: definitions, clinical outcomes, and treatment considerations. Nature reviews Urology 2017; 14(1): 15-25.
8. Foster CC, Weichselbaum RR, Pitroda SP. Oligometastatic prostate cancer: Reality or figment of imagination? Cancer 2019; 125(3): 340-52.
9. Triggiani L, Alongi F, Buglione M, et al. Efficacy of stereotactic body radiotherapy in oligorecurrent and in oligoprogressive prostate cancer: new evidence from a multicentric study. British journal of cancer 2017; 116(12): 1520-5.
10. Pembroke CA, Fortin B, Kopek N. Comparison of survival and prognostic factors in patients treated with stereotactic body radiotherapy for oligometastases or oligoprogression. Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology 2018; 127(3): 493-500.
11. Jorgensen T, Muller C, Kaalhus O, Danielsen HE, Tveter KJ. Extent of disease based on initial bone scan: important prognostic predictor for patients with metastatic prostatic cancer. Experience from the Scandinavian Prostatic Cancer Group Study No. 2 (SPCG-2). European urology 1995; 28(1): 40-6.
12. Gandaglia G, Karakiewicz PI, Briganti A, et al. Impact of the Site of Metastases on Survival in Patients with Metastatic Prostate Cancer. European urology 2015; 68(2): 325-34.
13. Gakis G, Boorjian SA, Briganti A, et al. The role of radical prostatectomy and lymph node dissection in lymph node-positive prostate cancer: a systematic review of the literature. European urology 2014; 66(2): 191-9.
14. von Bodman C, Godoy G, Chade DC, et al. Predicting biochemical recurrence-free survival for patients with positive pelvic lymph nodes at radical prostatectomy. The Journal of urology 2010; 184(1): 143-8.
15. Briganti A, Karnes JR, Da Pozzo LF, et al. Two positive nodes represent a significant cut-off value for cancer specific survival in patients with node positive prostate cancer. A new proposal based on a two-institution experience on 703 consecutive N+ patients treated with radical prostatectomy, extended pelvic lymph node dissection and adjuvant therapy. European urology 2009; 55(2): 261-70.
16. Francini E, Gray KP, Xie W, et al. Time of metastatic disease presentation and volume of disease are prognostic for metastatic hormone sensitive prostate cancer (mHSPC). 2018; 78(12): 889-95.
17. Linch M, Goh G, Hiley C, et al. Intratumoural evolutionary landscape of high-risk prostate cancer: the PROGENY study of genomic and immune parameters. Annals of oncology : official journal of the European Society for Medical Oncology 2017; 28(10): 2472-80.
18. Gundem G, Van Loo P, Kremeyer B, et al. The evolutionary history of lethal metastatic prostate cancer. Nature 2015; 520(7547): 353-7.
19. Cooper CS, Eeles R, Wedge DC, et al. Analysis of the genetic phylogeny of multifocal prostate cancer identifies multiple independent clonal expansions in neoplastic and morphologically normal prostate tissue. Nature genetics 2015; 47(4): 367-72.
20. Larbi A, Dallaudiere B, Pasoglou V, et al. Whole body MRI (WB-MRI) assessment of metastatic spread in prostate cancer: Therapeutic perspectives on targeted management of oligometastatic disease. The Prostate 2016; 76(11): 1024-33.
21. Graziani T, Ceci F, Castellucci P, et al. (11)C-Choline PET/CT for restaging prostate cancer. Results from 4,426 scans in a single-centre patient series. European journal of nuclear medicine and molecular imaging 2016; 43(11): 1971-9.
22. McAllister SS, Gifford AM, Greiner AL, et al. Systemic endocrine instigation of indolent tumor growth requires osteopontin. Cell 2008; 133(6): 994-1005.
23. Kaplan RN, Riba RD, Zacharoulis S, et al. VEGFR1-positive haematopoietic bone marrow progenitors initiate the pre-metastatic niche. Nature 2005; 438(7069): 820-7.
24. Bayne CE, Williams SB, Cooperberg MR, et al. Treatment of the Primary Tumor in Metastatic Prostate Cancer: Current Concepts and Future Perspectives. European urology 2016; 69(5): 775-87.
25. Locke JA, Dal Pra A, Supiot S, Warde P, Bristow RG. Synergistic action of image-guided radiotherapy and androgen deprivation therapy. Nature reviews Urology 2015; 12(4): 193-204.
26. Kalina JL, Neilson DS, Comber AP, et al. Immune Modulation by Androgen Deprivation and Radiation Therapy: Implications for Prostate Cancer Immunotherapy. Cancers (Basel) 2017; 9(2): 13.
27. Heidenreich A, Pfister D, Porres D. Cytoreductive radical prostatectomy in patients with prostate cancer and low volume skeletal metastases: results of a feasibility and case-control study. The Journal of urology 2015; 193(3): 832-8.
28. Bianchini D, Lorente D, Rescigno P, et al. Effect on Overall Survival of Locoregional Treatment in a Cohort of De Novo Metastatic Prostate Cancer Patients: A Single Institution Retrospective Analysis From the Royal Marsden Hospital. Clinical genitourinary cancer 2017; 15(5): e801-e7.
29. Gratzke C, Engel J, Stief CG. Role of radical prostatectomy in metastatic prostate cancer: data from the Munich Cancer Registry. European urology 2014; 66(3): 602-3.
30. Culp SH, Schellhammer PF, Williams MB. Might men diagnosed with metastatic prostate cancer benefit from definitive treatment of the primary tumor? A SEER-based study. European urology 2014; 65(6): 1058-66.
31. O'Shaughnessy MJ, McBride SM, Vargas HA, et al. A Pilot Study of a Multimodal Treatment Paradigm to Accelerate Drug Evaluations in Early-stage Metastatic Prostate Cancer. Urology 2017; 102: 164-72.
32. Satkunasivam R, Kim AE, Desai M, et al. Radical Prostatectomy or External Beam Radiation Therapy vs No Local Therapy for Survival Benefit in Metastatic Prostate Cancer: A SEER-Medicare Analysis. The Journal of urology 2015; 194(2): 378-85.
33. Loppenberg B, Dalela D, Karabon P, et al. The Impact of Local Treatment on Overall Survival in Patients with Metastatic Prostate Cancer on Diagnosis: A National Cancer Data Base Analysis. European urology 2017; 72(1): 14-9.
34. Boeve LMS, Hulshof M, Vis AN, et al. Effect on Survival of Androgen Deprivation Therapy Alone Compared to Androgen Deprivation Therapy Combined with Concurrent Radiation Therapy to the Prostate in Patients with Primary Bone Metastatic Prostate Cancer in a Prospective Randomised Clinical Trial: Data from the HORRAD Trial. European urology 2019; 75(3): 410-8.
35. Parker CC, James ND, Brawley CD, et al. Radiotherapy to the primary tumour for newly diagnosed, metastatic prostate cancer (STAMPEDE): a randomised controlled phase 3 trial. Lancet (London, England) 2018; 392(10162): 2353-66.
36. Sweeney CJ, Chen Y-H, Carducci M, et al. Chemohormonal Therapy in Metastatic Hormone-Sensitive Prostate Cancer. New England Journal of Medicine 2015; 373(8): 737-46.
37. Burdett S, Boeve LM, Ingleby FC, et al. Prostate Radiotherapy for Metastatic Hormone-sensitive Prostate Cancer: A STOPCAP Systematic Review and Meta-analysis. European urology 2019; 76(1): 115-24.
38. Potters L, Kavanagh B, Galvin JM, et al. American Society for Therapeutic Radiology and Oncology (ASTRO) and American College of Radiology (ACR) practice guideline for the performance of stereotactic body radiation therapy. International journal of radiation oncology, biology, physics 2010; 76(2): 326-32.
39. De Bleser E, Tran PT, Ost P. Radiotherapy as metastasis-directed therapy for oligometastatic prostate cancer. Current opinion in urology 2017; 27(6): 587-95.
40. Decaestecker K, De Meerleer G, Lambert B, et al. Repeated stereotactic body radiotherapy for oligometastatic prostate cancer recurrence. Radiat Oncol 2014; 9: 135-.
41. Palma DA, Salama JK, Lo SS, et al. The oligometastatic state - separating truth from wishful thinking. Nature reviews Clinical oncology 2014; 11(9): 549-57.
42. Riva G, Marvaso G, Augugliaro M, et al. Cytoreductive prostate radiotherapy in oligometastatic prostate cancer: a single centre analysis of toxicity and clinical outcome. Ecancermedicalscience 2017; 11: 786.
43. Ost P, Reynders D, Decaestecker K, et al. Surveillance or Metastasis-Directed Therapy for Oligometastatic Prostate Cancer Recurrence: A Prospective, Randomized, Multicenter Phase II Trial. Journal of clinical oncology : official journal of the American Society of Clinical Oncology 2018; 36(5): 446-53.
44. Nguyen PL, Alibhai SM, Basaria S, et al. Adverse effects of androgen deprivation therapy and strategies to mitigate them. European urology 2015; 67(5): 825-36.
45. Duchesne GM, Woo HH, Bassett JK, et al. Timing of androgen-deprivation therapy in patients with prostate cancer with a rising PSA (TROG 03.06 and VCOG PR 01-03 [TOAD]): a randomised, multicentre, non-blinded, phase 3 trial. The Lancet Oncology 2016; 17(6): 727-37.
46. Ost P, Bossi A, Decaestecker K, et al. Metastasis-directed therapy of regional and distant recurrences after curative treatment of prostate cancer: a systematic review of the literature. European urology 2015; 67(5): 852-63.
47. Steuber T, Jilg C, Tennstedt P, et al. Standard of Care Versus Metastases-directed Therapy for PET-detected Nodal Oligorecurrent Prostate Cancer Following Multimodality Treatment: A Multi-institutional Case-control Study. European urology focus 2018.
48. Siva S, Bressel M, Murphy DG, et al. Stereotactic Abative Body Radiotherapy (SABR) for Oligometastatic Prostate Cancer: A Prospective Clinical Trial. European urology 2018; 74(4): 455-62.
49. Ploussard G, Gandaglia G, Borgmann H, et al. Salvage Lymph Node Dissection for Nodal Recurrent Prostate Cancer: A Systematic Review. European urology 2018.
50. Zattoni F, Nehra A, Murphy CR, et al. Mid-term Outcomes Following Salvage Lymph Node Dissection for Prostate Cancer Nodal Recurrence Status Post-radical Prostatectomy. European urology focus 2016; 2(5): 522-31.
51. Fossati N, Suardi N, Gandaglia G, et al. Identifying the Optimal Candidate for Salvage Lymph Node Dissection for Nodal Recurrence of Prostate Cancer: Results from a Large, Multi-institutional Analysis. European urology 2019; 75(1): 176-83.
52. Standard Systemic Therapy With or Without Definitive Treatment in Treating Participants With Metastatic Prostate Cancer. 2019. https://clinicaltrials.gov/ct2/show/NCT03678025. (accessed August 8th 2019).
53. Stereotactic Body Radiation for Prostate Oligometastases (ORIOLE). NCT02680587. 2019. https://clinicaltrials.gov/ct2/show/ (accessed August 8th 2019).
54. Radwan N, Phillips R, Ross A, et al. A phase II randomized trial of Observation versus stereotactic ablative RadiatIon for OLigometastatic prostate CancEr (ORIOLE). BMC cancer 2017; 17(1): 453.
55. Rowe SP, Macura KJ, Mena E, et al. PSMA-Based [(18)F]DCFPyL PET/CT Is Superior to Conventional Imaging for Lesion Detection in Patients with Metastatic Prostate Cancer. Mol Imaging Biol 2016; 18(3): 411-9.
56. Sooriakumaran P. Testing radical prostatectomy in men with prostate cancer and oligometastases to the bone: a randomized controlled feasibility trial. BJU international 2017; 120(5b): E8-e20.

The Current Landscape of Metastatic Castration-Resistant Prostate Cancer: Novel Hormonal Therapies

While the emergence of castration resistant disease comes as a result of the disease progressing in spite of castrate levels of testosterone (at times called hormone refractory disease), prostate cancer (even in the castration resistance prostate cancer (CRPC) setting) remains heavily dependent on the androgen axis. Thus, novel treatment approaches have targeted other aspects of these signaling pathways with considerable clinical benefit. This mCRPC Center of Excellence article will focus on treatment advances related to novel hormonal therapies (NHTs).

Written by: Christopher J.D. Wallis, MD, PhD, Rashid Sayyid, MD MSc, & Zachary Klaassen, MD MSc
References:
  1. de Bono JS, Logothetis CJ, Molina A, et al. Abiraterone and increased survival in metastatic prostate cancer. N Engl J Med. 2011;364(21):1995-2005
  2. Ryan CJ, Smith MR, de Bono JS, et al. Abiraterone in metastatic prostate cancer without previous chemotherapy. N Engl J Med. 2013;368(2):138-148.
  3. Scher HI, Fizazi K, Saad F, et al. Increased survival with enzalutamide in prostate cancer after chemotherapy. New Engl J Med. 2012;367(13):1187-1197.
  4. Beer TM, Armstrong AJ, Rathkopf DE, et al. Enzalutamide in metastatic prostate cancer before chemotherapy. N Engl J Med. 2014;371(5):424-433.
  5. Beer TM, Armstrong AJ, Rathkopf D, et al. Enzalutamide in Men with Chemotherapy-naive Metastatic Castration-resistant Prostate Cancer: Extended Analysis of the Phase 3 PREVAIL Study. Eur Urol. 2016.
  6. Denmeade SR, Wang H, Agarwal N, et al. TRANSFORMER: A Randomized Phase II Study Comparing Bipolar Androgen Therapy Versus Enzalutamide in Asymptomatic Men With Castration-Resistant Metastatic Prostate Cancer. J Clin Oncol. 2021;39(12):1371-1382.
  7. Bipolar Androgen Therapy in Men with Metastatic Castration-resistant Prostate Cancer (RESTORE): A Comparison of Post-abiraterone Versus Post-enzalutamide Cohorts. Eur Urol. 2021;692-699.
  8. Khalaf DJ, Annala M, Taavitsainen S, et al. Optimal sequencing of enzalutamide and abiraterone acetate plus prednisone in metastatic castration-resistant prostate cancer: a multicentre, randomised, open-label, phase 2, crossover trial. Lancet Oncol. 2019l20(12):1730-1739.
  9. Saad F, Efstathiou E, Attard G, et al. Apalutamide plus abiraterone acetate and prednisone versus placebo plus abiraterone and prednisone in metastatic, castration-resistant prostate cancer (ACIS): a randomised, placebo-controlled, double-blind, multinational, phase 3 study. Lancet Oncol. 2021;22(11):1541-1559.
  10. Colomba E, Jonas SF, Eymard J-C, et al. Objective computerized cognitive assessment in men with metastatic castrate-resistant prostate cancer (mCRPC) randomly receiving darolutamide or enzalutamide in the ODENZA trial. Ann Oncol. 2021;32(5):S66-647.
  11. Cathomas R, Procopio G, Hayoz S, et al. Darolutamide maintenance in metastatic castration resistant prostate cancer (mCRPC) previously treated with novel hormonal agents (NHA) and non-progressive disease after subsequent treatment with a taxane: A randomized double-blind placebo-controlled phase II trial (SAKK 08/16). Ann Oncol. 2021;32(5):S1301-1302.

 

 

Prostate Cancer Survivorship

Physical Side Effects


Urinary Dysfunction

Urinary dysfunction is a side effect of both surgical and radiotherapy (RT) for local treatment of prostate cancer (PCa). Surgical side effects typically include a period of urinary incontinence for several months postoperatively followed by a degree of stress urinary incontinence that may persist for months or even years. RT-induced urinary dysfunction typically manifests as bladder irritability/overactivity either during treatment or shortly thereafter. Longer-term urinary dysfunction issues after RT may include urethral strictures necessitating periodic interventions and/or catheterization.

The ProtecT trial randomized 1,643 men from 1999 to 2009 to undergoing either active monitoring (n=545), surgery (n=553), or RT (n=545), finding that at a median 10 years of follow-up, PCa-specific mortality was low irrespective of treatment.2 As part of this trial, patient-reported outcomes were collected and have now become one of the benchmarks for counseling patients with regards to long-term side effects of treatment for localized PCa treatment.3 Questionnaires were completed at the time of diagnosis, at 6 and 12 months after randomization, and annually thereafter. Patients completed validated measures that assessed urinary, bowel, and sexual function and specific effects on quality of life, anxiety, and depression, and general health. The rate of questionnaire completion during follow-up was outstanding at >85% for most measures. Regarding urinary dysfunction, radical prostatectomy (RP) had the greatest negative effect on urinary continence, and although there was some recovery over time, these patients remained worse throughout follow-up compared to patients undergoing active monitoring or RT. Interestingly, RT had little effect on urinary incontinence, and there was a gradual decrease in urinary function over time for the men undergoing active monitoring. Urinary voiding and nocturia were worse in the radiotherapy group at 6 months but then mostly recovered and were similar to the other groups after 12 months. Urinary incontinence has been cited as being the most important factor for decision regret among receiving local therapy for PCa and may be incompletely explained/discussed with ~80% of patients prior to undergoing treatment.4

Sexual Dysfunction

Similar to urinary dysfunction, sexual dysfunction is a common side effect of localized therapy for PCa. Patients undergoing RP will suffer a degree of sexual dysfunction in the immediate postoperative period with a degree of recovering over 12-24 months after surgery. Many studies have been published assessing predictors of postoperative recovery of sexual function, commonly highlighting younger age and adequate function pre-operatively as predictors of post-operative recovery. Men undergoing RT, similar to urinary dysfunction, will not notice an immediate effect on sexual function during the treatment phase, but generally, suffer sexual dysfunction in the years post-radiation.

In the ProtecT trial, RP incurred the greatest degree of sexual dysfunction among all three treatment arms, with some recovery of function over time.3 The negative effect of RT on sexual function was greatest at 6 months, but sexual function then recovered somewhat and was stable thereafter. Sexual dysfunction also declined in the active monitoring group over time.

Primarily secondary to the sexual side effects of localized treatment for PCa, many cancer centers now have fellowship-trained experts that see these patients concomitantly with the oncologist. There are a variety of treatment options offered, including oral PDE-5 inhibitors (sildenafil, tadalafil, etc.), intracavernosal injection therapy, and penile prosthetics.

Bowel Dysfunction

Bowel dysfunction is typically low for patients undergoing RP or active surveillance (AS) but may be a detrimental side effect among men undergoing RT. In the ProtecT trial, bowel function was worse in the RT group at 6 months than in the other groups but then recovered somewhat, except for the increasing frequency of bloody stools; bowel function was unchanged in the active monitoring and RP groups.3

Bowel dysfunction and rectal toxicity has improved with the recent FDA approval of hydrogel rectal spacers. Prior to RT, patients may have a hydrogel rectal spacer (SpaceOAR®) placed in a transperineal fashion in the fat between the rectum and Denonvilliers' fascia. In the pivotal clinical trial assessing hydrogel spacers, 114 patients were enrolled between 2010 and 2011 with 54 patients selected for a hydrogel injection before the beginning of RT.5 Patients were surveyed at various time-points with the EPIC PCa questionnaire – among patients treated with a hydrogel spacer, mean bowel function and bother score changes of >5 points in comparison with baseline levels were found only at the end of RT (10-15 points; p < 0.01). Mean bowel bother score changes of 21 points at the end of RT, 8 points at 2 months, 7 points at 17 months, and 6 points at 63 months after RT were found for patients treated without a spacer. These bowel quality of life results have given hydrogel spacers an option among patients considering RT.

Other health-related effects

There is evidence that both RT and androgen deprivation therapy (ADT) may contribute to the development of coronary heart disease, sudden cardiac death, myocardial infarction, and skeletal-related events such as fracture.6

Psychological Side Effects

Depression and Anxiety

Depression is the most common psychiatric comorbidity among cancer patients, including patients with PCa. Ravi et al.7 previously utilized the SEER-Medicare database to assess the burden of mental health issues (anxiety, major depressive disorder, suicide) in patients with localized PCa. Among 50,586 men >65 years of age without a diagnosis of mental illness, 20.4% of men developed a mental illness with a median 55-month follow-up. Interestingly, patients undergoing WW (29.7%) and RT (29.0%) had a significantly increased incidence of mental illness compared to patients undergoing RP (22.6%; p<0.001). A systematic review of depression and anxiety in patients with PCa identified 27 articles comprising 4,494 patients.8 The meta-analysis of prevalence rates identified pretreatment prevalence of depression of 17.27% (95% confidence interval (CI) 15.06%-19.72%), on-treatment prevalence of 14.70% (95% CI 15.06%-19.72%) and post-treatment prevalence of 18.44% (95% CI 15.18%-22.22%). For anxiety, pretreatment prevalence was 27.04% (95% CI 24.26%-30.01%), on-treatment was 15.09% (95% CI 12.15%-18.60%) and post-treatment was 18.49% (95% CI 13.81%-24.31%). For patients undergoing AS, nearly one-third of patients (29%) report cancer-specific anxiety in the year following diagnosis.9 Interestingly, over time, this anxiety decreased significantly.

There is also increasing evidence that ADT for locally advanced and metastatic PCa is associated with depression. A study from 2016 using SEER-Medicare data found that men that received ADT, compared with patients who did not receive ADT, had higher 3-year cumulative incidences of depression (7.1% v 5.2), inpatient psychiatric treatment (2.8% v 1.9%), and outpatient psychiatric treatment (3.4% v 2.5%).10 Furthermore, the risk of depression increased with the duration of ADT, from 12% with ≤ 6 months of treatment, 26% with 7 to 11 months of treatment, to 37% with ≥ 12 months of treatment. A recent meta-analysis of 18 studies among 168,756 men found that ADT use conferred a 41% increased risk of depression (RR 1.41, 95%CI 1.18-1.70).11 These results were consistent when limiting the analysis to studies in localized disease (relative risk (RR) 1.85, 95%CI 1.20-2.85). Interestingly, this analysis did not find an association for continuous ADT with depression risk compared to intermittent ADT (RR 1.00, 95%CI 0.50-1.99).

Suicidal Risk

Patients with PCa have been shown to be at increased risk of suicide across several population-level studies. In a SEER analysis assessing suicide risk among patients with genitourinary malignancies from 1988-2010, Klaassen et al.12 found an age-adjusted standardized mortality ratio (SMR) of 1.37 for patients with PCa (95%CI, 0.99-1.86) Increasing age, metastatic disease and Caucasian race were risk factors for suicide among these patients. Interestingly, even patients >15 years after diagnosis were at increased risk of suicide compared to the general population (SMR 1.84, 95%CI 1.39-2.41). In an assessment of PCa suicidal risk compared to individuals with other malignancies, Dalela et al.13 found that risk of suicidal death was no different in men with PCa (1,165 [0.2%]) compared to men with other cancers (2,232 [0.2%]), However, within the first year of diagnosis, men with PCa had an increased risk of suicide (absolute risk reduction (ARR) 3.98, 95% CI 3.02-5.23 0-3 months after diagnosis). Furthermore, men with non-metastatic PCa who were Caucasian, uninsured, or recommended but did not receive treatment (hazard ratio (HR) vs treated 1.44, 95%CI 1.20-1.72) were at increased risk of suicidal death.

A meta-analysis of observational studies assessing incidence and risk factors of suicide after PCa diagnosis was recently published.14 This study included 8 observational studies involving 1,281,393 men diagnosed with PCa and 842,294 matched PCa-free men. Guo et al. found an overall increased relative risk of suicide of 2.01 (95% CI 1.52-2.64) among men diagnosed with PCa compared with those without PCa during the first year after diagnosis, particularly during the first 6 months after diagnosis (RR   2.24, 95%CI 1.77-2.85). Additionally, PCa patients were at an increased risk of suicide among men aged 75 years or older (RR  1.51, 95% CI 1.04-2.18) and for those treated with ADT (RR  1.80, 95% CI 1.54-2.12).

Until recently, all population-level studies assessing risk of suicide among PCa patients have not accounted for psychiatric comorbidities at the time of diagnosis. This is important, considering that being unable to adjust for psychiatric comorbidities makes it impossible to assess the true risk associated with a PCa diagnosis on suicidal risk. At the AUA 2019 annual meeting, Klaassen et al.15 presented data assessing all residents of Ontario, Canada diagnosed with either prostate, bladder or kidney cancer (1997-2014). Each patient was assigned a psychiatric utilization gradient (PUG) score in the five years prior to cancer diagnosis: 0 (none), 1 (outpatient), 2 (emergency department), 3 (hospital admission). Non-cancer controls were matched 4:1 to cancer patients based on sociodemographic variables and a marginal cause-specific hazard model was used to assess the effect of cancer on the risk of suicidal death. Among 191,068 patients included (137,699 PCa, 29,884 bladder cancer, 23,485 kidney cancer), 109,154 (57.1%) were PUG score 0, 79,553 (41.6%) PUG score 1, 1,596 (0.84%) PUG score 2, and 765 (0.40%) PUG score 3. Patients with genitourinary cancer had a higher risk of dying of suicide compared to controls (HR 1.16, 95%CI 1.00-1.36). Specifically, among individuals with PUG score 0, those with cancer were significantly more likely to die of suicide compared to patients without cancer (HR 1.39, 95%CI 1.12-1.74).

Guideline Recommendations

The Commission on Cancer requires cancer programs to develop and implement processes to monitor formation and dissemination of a survivorship care plan for all cancer patients with stage I-III disease treated with curative intent, and to have this plan in place within 1-year of diagnosis of cancer and no later than 6 months after completing adjuvant therapy.16 Guideline recommendations for PCa survivorship have primarily been driven by the American Cancer Society (ACS) and the American Society of Clinical Oncology (ASCO). The ACS noted in their 2014 guideline that survivorship should promote comprehensive follow-up care and optimal health and quality of life for the post-treatment PCa survivor.17 The guidelines also address health promotion, surveillance for PCa recurrence, screening for second primary cancers, long-term and late effects assessment and management, psychosocial issues, and care coordination among the oncology team, primary care clinicians, and non-oncology specialists. Subsequently, the ASCO Endorsement Panel reviewed the ACS guidelines, endorsing these guidelines with the following recommendations:18

• Measure PSA level every 6 to 12 months for the first 5 years and then annually, considering more frequent evaluation in men at high risk for recurrence and in candidates for salvage therapy. 

• Refer survivors with elevated or increasing PSA levels back to their primary treating physician for evaluation and management.

• Adhere to ACS guidelines for the early detection of cancer.

• Assess and manage physical and psychosocial effects of PCa and its treatment.

• Annually assess for the presence of long-term or late effects of PCa and its treatment.

Screening Measures

There are several screening tools to assess for quality of life, depression and suicidal risk. A study from 2017 assessed differences in the scores, relative severity and major depressive disorder from three standardized self-report scales for depression in PCa patients [The Hospital Anxiety and Depression Scale Depression subscale (HADS-D), the Self-rating Depression Scale (SDS) and the Patient Health Questionnaire (PHQ-9) for depression].19 Among 138 PCa patients, despite significant correlations between the total scores from the three scales, severity classification differed across the three scales. Furthermore, there was considerable underestimation of depression by the HADS-D compared to the PHQ-9 and a similar tendency for the SDS. This study highlights that scale construction and depression items included can produce different results across scales, making inter-study comparisons difficult. Despite these findings, we recommend that at minimum oncologists should be using at least one depression index to assess patient well-being at each clinic visit.

In addition to the aforementioned HADS-D, SDS, and PHQ-9 metrics, the National Comprehensive Cancer Network (NCCN) provides a guideline for identifying and explaining risk factors in patients with cancer, in addition to providing a “distress thermometer”. The NCCN defines distress, in the setting of cancer, as a multifactorial emotional experience of a psychological, social, and/or spiritual nature that may interfere with the ability to cope effectively with the diagnosis.20 Distress can range from sadness and fear to more disabling symptoms such as anxiety and depression. Furthermore, the time periods at which patients are at increased vulnerability begin with the realization of a suspicious symptom, all the way through to failure/disease recurrence and near the end of life. The NCCN recommends screening all patients for distress to recognize, monitor, and treat patients effectively.20

Previous work has also suggested that screening for depression and erectile dysfunction may be a way to decrease suicidal risk among PCa patients.21 A proposed algorithm allows for an initial evaluation with the EPIC-CP and PHQ-9 tools to assess for health-related quality of life and depression, respectively. If the EPIC-CP or PHQ-9 are negative for depression or erectile dysfunction, these tools should still be used at each visit to regularly evaluate patients. If EPIC-CP or PHQ-9 suggest problems with depression or erectile dysfunction, then an 8-question suicidal ideation questionnaire (adapted from Recklitis et al.22) should be completed. If the suicidal ideation questionnaire demonstrates any level of suicidal ideation, clinicians should make an urgent referral for psychiatric evaluation. This is particularly true when the patient has the concomitant high-risk suicidal risk profile of being elderly, white, single, or with high-risk or disease progression. Given that, at maximum, the patient must answer a 27-point composite questionnaire, this should be feasible in the busy clinical setting and can be provided to the patient at appointment check-in and completed in the waiting room before the physician-patient encounter. Regardless of the results from these screening tools, if any member of the healthcare team has an index of suspicion for suicidal ideation, the physician should immediately make a referral for psychiatric evaluation.

Conclusions

With nearly 3 million men in the United States living with PCa, survivorship programs are now mandated by the Commission on Cancer and play an integral role in health and well-being of men with PCa. In addition to the physical side effects of treatment that should be addressed at each clinic visit, there are crucial psychiatric side effects, including depression, anxiety, and suicidal ideation that should be screened for and recognized by all members of the healthcare team.

Published Date: December 2019
Written by: Zachary Klaassen, MD, MSc and Christopher J.D. Wallis, MD, PhD
References: 1. Siegel RL, Miller KD, Jemal A. Cancer statistics, 2019. CA Cancer J Clin. 2019;69(1):7-34.
2. Hamdy FC, Donovan JL, Lane JA, et al. 10-Year Outcomes after Monitoring, Surgery, or Radiotherapy for Localized Prostate Cancer. N Engl J Med. 2016;375(15):1415-1424.
3. Donovan JL, Hamdy FC, Lane JA, et al. Patient-Reported Outcomes after Monitoring, Surgery, or Radiotherapy for Prostate Cancer. N Engl J Med. 2016;375(15):1425-1437.
4. Albkri A, Girier D, Mestre A, Costa P, Droupy S, Chevrot A. Urinary Incontinence, Patient Satisfaction, and Decisional Regret after Prostate Cancer Treatment: A French National Study. Urol Int. 2018;100(1):50-56.
5. Pinkawa M, Berneking V, Schlenter M, Krenkel B, Eble MJ. Quality of Life After Radiation Therapy for Prostate Cancer With a Hydrogel Spacer: 5-Year Results. Int J Radiat Oncol Biol Phys. 2017;99(2):374-377.
6. Wallis CJ, Mahar AL, Satkunasivam R, et al. Cardiovascular and Skeletal-related Events Following Localized Prostate Cancer Treatment: Role of Surgery, Radiotherapy, and Androgen Deprivation. Urology. 2016;97:145-152.
7. Ravi P, Karakiewicz PI, Roghmann F, et al. Mental health outcomes in elderly men with prostate cancer. Urol Oncol. 2014;32(8):1333-1340.
8. Watts S, Leydon G, Birch B, et al. Depression and anxiety in prostate cancer: a systematic review and meta-analysis of prevalence rates. BMJ Open. 2014;4(3):e003901.
9. Marzouk K, Assel M, Ehdaie B, Vickers A. Long-Term Cancer Specific Anxiety in Men Undergoing Active Surveillance of Prostate Cancer: Findings from a Large Prospective Cohort. J Urol. 2018;200(6):1250-1255.
10. Dinh KT, Reznor G, Muralidhar V, et al. Association of Androgen Deprivation Therapy With Depression in Localized Prostate Cancer. J Clin Oncol. 2016;34(16):1905-1912.
11. Nead KT, Sinha S, Yang DD, Nguyen PL. Association of androgen deprivation therapy and depression in the treatment of prostate cancer: A systematic review and meta-analysis. Urol Oncol. 2017;35(11):664 e661-664 e669.
12. Klaassen Z, Jen RP, DiBianco JM, et al. Factors associated with suicide in patients with genitourinary malignancies. Cancer. 2015;121(11):1864-1872.
13. Dalela D, Krishna N, Okwara J, et al. Suicide and accidental deaths among patients with non-metastatic prostate cancer. BJU Int. 2016;118(2):286-297.
14. Guo Z, Gan S, Li Y, et al. Incidence and risk factors of suicide after a prostate cancer diagnosis: a meta-analysis of observational studies. Prostate Cancer Prostatic Dis. 2018;21(4):499-508.
15. Klaassen Z, Wallis CJ, Goldberg H, et al. Utilization of Psychiatric Resources Prior to Genitourinary (GU) Cancer Diagnosis: Implications for Survival Outcomes. AUA 2019. 2019.
16. Fashoyin-Aje LA, Martinez KA, Dy SM. New patient-centered care standards from the commission on cancer: opportunities and challenges. J Support Oncol. 2012;10(3):107-111.
17. Skolarus TA, Wolf AM, Erb NL, et al. American Cancer Society prostate cancer survivorship care guidelines. CA Cancer J Clin. 2014;64(4):225-249.
18. Resnick MJ, Lacchetti C, Bergman J, et al. Prostate cancer survivorship care guideline: American Society of Clinical Oncology Clinical Practice Guideline endorsement. J Clin Oncol. 2015;33(9):1078-1085.
19. Sharpley CF, Bitsika V, Christie DR, Hunter MS. Measuring depression in prostate cancer patients: does the scale used make a difference? Eur J Cancer Care (Engl). 2017;26(1).
20. National Comprehensive Cancer N. Distress management. Clinical practice guidelines. J Natl Compr Canc Netw. 2003;1(3):344-374.
21. Klaassen Z, Arora K, Wilson SN, et al. Decreasing suicide risk among patients with prostate cancer: Implications for depression, erectile dysfunction, and suicidal ideation screening. Urol Oncol. 2018;36(2):60-66.
22. Recklitis CJ, Zhou ES, Zwemer EK, Hu JC, Kantoff PW. Suicidal ideation in prostate cancer survivors: understanding the role of physical and psychological health outcomes. Cancer. 2014;120(21):3393-3400.

The Current Landscape of Metastatic Castration-Resistant Prostate Cancer: Nearly Two Decades of Treatment Options

Prostate cancer, while commonly diagnosed as localized disease, remains the second leading cause of cancer mortality in the United States and Europe.1 For patients who die of prostate cancer, some will be initially diagnosed and treated for metastatic hormone-sensitive disease (mHSPC) while others will progress from an initial diagnosis of localized disease through non-metastatic castration-resistant disease (nmCPRC) following initial local therapy with subsequent androgen deprivation therapy (ADT) for biochemical recurrence.

Written by: Zachary Klaassen, MD MSc, Rashid Sayyid, MD MSc, and Christopher J.D. Wallis, MD PhD
References:
  1. Tannock IF, de Wit R, Berry WR, et al. Docetaxel plus prednisone or mitoxantrone plus prednisone for advanced prostate cancer. N Engl J Med. 2004;351(15):1502-1512.
  2. Tannock IF, Osoba D, Stockler MR, et al. Chemotherapy with mitoxantrone plus prednisone or prednisone alone for symptomatic hormone-resistant prostate cancer: a Canadian randomized trial with palliative end points. J Clin Oncol. 1996:14(6):1756-1764.
  3. Osoba D, Tannock IF, Ernst DS, Neville AJ. Health-related quality of life in men with metastatic prostate cancer treated with prednisone alone or mitoxantrone and prednisone. J Clin Oncol. 1999;17(6):1654-1663.
  4. de Bono JS, Oudard S, Ozguroglu M, et al. Prednisone plus cabazitaxel or mitoxantrone for metastatic castration-resistant prostate cancer progressing after docetaxel treatment: a randomised open-label trial. Lancet. 2010;376(9747):1147-1154.
  5. de Wit R, de Bono J, Sternberg CN, et al. Cabazitaxel versus Abiraterone or Enzalutamide in Metastatic Prostate Cancer. N Engl J Med. 2019;381(26):2506-2518.
  6. Morgans AK, Hutson T, Guan AKD, et al. An economic evaluation of cabazitaxel versus a second androgen receptor-targeted agent (ARTA) for patients with metastatic castration-resistant prostate cancer previously treated with docetaxel and an ARTA: the United States payer perspective. BMC Health Serv Res. 2022;22(1):916.

The Current Status of Immunotherapy for Prostate Cancer

The Prostate Cancer Immune Microenvironment

The microenvironment associated with prostate cancer includes low cytolytic activity of natural killer (NK) cells,5 high secretion of TGF-beta by prostate tissue (which inhibits NK and lymphocyte function),6 and recruitment of T regulatory cells that down-regulate antitumor immunity.7 As such, the prostate cancer microenvironment has been described as an immunosuppressive state. Furthermore, based on the chronicity of the prostate cancer disease spectrum, the immune microenvironment is likely dynamic, with changes over time/clinical states and with treatment exposure.8 For example, there are increased tumor-infiltrating lymphocytes in the prostate bed following androgen deprivation therapy,9 and higher levels of PD-1 ligand and PD-L2 expression on the surface of enzalutamide-treated prostate cancer cells.10 Several aspects make prostate cancer attractive for immunotherapy-based treatment options, including a high-level of tumor-associated antigens such as prostate-specific antigen (PSA), prostate acid phosphatase (PAP), and prostate-specific membrane antigen (PSMA).

Cell-based vaccines

Cell-based vaccines consist of whole cells that are modified in order to induce anti-tumor immune responses. Sipuleucel-T is an autologous vaccine processed following peripheral dendritic cell collection via leukapheresis. This is then incubated with GCS-F and PAP protein, followed by reinfusion into the patient (after a 36-44 hour period) in order to generate a PAP-specific CD4+ and CD8+ T cell response.11,12

Sipuleucel-T was FDA approved based on results of the Phase III IMPACT clinical trial.1 This trial enrolled 512 patients with mCRPC who had asymptomatic disease/minimally symptomatic with no visceral metastases, randomizing men to three infusions of sipuleucel-T (n=341) or placebo (n=171). The IMPACT trial noted a 4.1-month improvement in overall survival (OS) for those taking sipuleucel-T compared to placebo and a 22% reduction in risk of death. There was no difference between the groups with regards to objective disease progression or PSA response (secondary endpoints). An assessment of safety profile for patients in this study found that the treatment was overall well tolerated with minimal concern for severe adverse events.13 Furthermore, immunologic assessment showed that patients with high antibody titers against PA2024 benefited the most from treatment, noting longer survival.1 Despite the results and safety profile of IMPACT, reported nearly a decade ago, the use of sipuleucel-T has not been widely adopted primarily due to the lack of cost-effectiveness and the infrastructure required to administer this treatment.

Vector-based vaccines

Vector-based vaccines consist of genetically engineered nucleic acids that encode specific tumor-associated antigens transmitted by vectors such as bacterial plasmids or viruses. DNA-based vaccines can be incorporated by host cells and generate an immune response to recruiting antigen-presenting cells. pTVG-HP is a DNA plasmid vector vaccine that encodes PAP protein. pTVG-HP has been tested in the non-metastatic CRPC setting, demonstrating increased PSA doubling time from 6.5 months to 9.3 months after one year of treatment.14

PROSTVAC is a PSA-target pox-virus-based vaccine. PROSTVAC was tested in a Phase II study of 125 patients with minimally symptomatic mCRPC who were randomized to receive the vaccine or placebo.15 Although the study was negative for its primary endpoint of progression-free survival (PFS), OS after 3 years of follow-up was significantly increased by 8.5 months (25.1 vs 16.6 months; HR 0.56; p=0.0061).

PROSTVAC was subsequently tested in a Phase III trial that reported results earlier this year.16 Patients were randomly assigned to PROSTVAC (n = 432), PROSTVAC plus granulocyte-macrophage colony-stimulating (GMCS) factor (n = 432), or placebo (n = 433), stratified by PSA (< 50 ng/mL vs. >= 50 ng/mL) and lactate dehydrogenase (< 200 vs >= 200 U/L). The primary endpoint for this trial was OS, and secondary endpoints were patients alive without events (AWE): radiographic progression, pain progression, chemotherapy initiation, or death at 6 months. Unfortunately, neither active treatment had an effect on median OS: (i) PROSTVAC: 34.4 months, hazard ratio (HR) 1.01, 95% confidence interval (CI) 0.84-1.20 (ii) PROSTVAC plus GMCS factor: 33.2 months, HR 1.02, 95% CI 0.86-1.22 (iii) placebo: 34.3 months. Furthermore, AWE at 6 months was similar between the arms. Based on these results, the authors noted that focus is currently ongoing for combination therapies.

DCVAC/PCa is an autologous dendritic cell vaccine derived from mononuclear cells that are pulsed with killed prostate cancer cells. In a Phase I/II trial, there were 25 men with mCRPC that received DCVAC/PCa plus docetaxel, demonstrating good tolerability and a median OS of 19 months.17 Currently, there is a Phase III (VIABLE) trial of DCVAC/PCa ongoing, which began accrual in 2014, with a target of 1,170 patients and planned completion date in 2020.

Immune Checkpoint inhibitors

Checkpoint inhibitors are antibodies that target molecules, such as cytotoxic T-lymphocyte protein 4 (CTLA-4) or PD-1 and its ligand PD-L1. Among men with mCRPC, ipilimumab was tested in the Phase III for those who had progressed on docetaxel chemotherapy, randomizing 799 patients to ipilimumab or placebo after bone-directed radiotherapy.18 The primary endpoint was OS, with no difference between the groups (ipilimumab 11.2 months vs placebo 10 months; HR 0.85, p=0.053); however, there was a small benefit in PFS favoring ipilimumab (4.0 vs 3.1 months; HR 0.70, p < 0.0001). More recently, Beer et al.19 reported findings of another Phase III trial randomizing 602 patients (2:1) with metastatic chemotherapy-naïve CRPC to ipilimumab vs placebo. Similar to the post-docetaxel patients, there was no difference in OS between the groups (HR 1.11, 95% CI 0.88-1.39), however men receiving ipilimumab had improved PFS (5.6 months vs 3.8; HR 0.67, 95% CI 0.55-0.81) compared to those receiving placebo.

Pembrolizumab has recently moved into the mCRPC arena, receiving FDA approval in a tumor agnostic indication for MSI-high (MSI-H) mutation CRPC patients in 2017. A study from the Memorial Sloan Kettering Cancer Center assessed the prevalence of MSI-H/dMMR prostate cancer among 1,033 patients treated at their institution,20 finding that 32 (3.1%) had MSI-H/dMMR disease. This included 23 patients (2.2%) that had tumors with high MSIsensor scores, and 7 of the 32 MSI-H/dMMR patients (21.9%) with pathogenic germline mutation in a Lynch syndrome-associated gene. Eleven patients with MSI-H/dMMR CRPC received anti-PD-1/PD-L1 therapy and six of these had a greater than 50% decline in PSA levels. Based on these data, experts in the field of advanced prostate cancer feel that every mCRPC patient should be tested for MSI-H status and potential pembrolizumab eligibility.

The KEYNOTE-028 study was a trial of pembrolizumab in advanced solid tumors among patients with PD-1 expression ≥1% of tumor or stromal cells. Among 245 men screened, there were 35 PD-1% (14.3%) and 23 patients who enrolled.21 There were four partial responses, for an objective response rate of 17.4% and 8 of 23 (34.8%) patients had stable disease. Median duration of response was 13.5  months, and median PFS and OS were 3.5 and 7.9 months, respectively. Furthermore, the 6-month PFS and OS rates were 34.8% and 73.4%, respectively. Recently, off-label use of pembrolizumab among a heavily pre-treated population of mCRPC patients has recently been reported. At the 2019 ASCO GU meeting, Tucker and colleagues presented data on 51 patients, 86% of which had received three or more prior lines of therapy. Most patients had previously received abiraterone (88%), docetaxel (86%), enzalutamide (80%), and sipuleucel-T (74%). Among these patients, 16% had a >50% confirmed PSA decline with pembrolizumab, with 8% having >90% PSA decline. Fifty-nine percent of men were treated with some form of concurrent therapy along with pembrolizumab, most commonly enzalutamide (47%).

At the 2019 ASCO GU meeting, results of the Phase II KEYNOTE-650 were also presented. This trial tested the combination of nivolumab plus ipilimumab for men with mCRPC. There were two cohorts for this study: cohort 1 – asymptomatic or minimally symptomatic, who had progressed after at least 1 second generation hormone therapy with no prior chemotherapy, and cohort 2 – progression after chemotherapy. Overall response rates were 26% in cohort 1 and 10% in cohort 2, including two patients in each cohort who had a complete response. Median time to response was approximately two months. PSA response rate was 18% in cohort 1 and 10% in cohort 2.

Future Directions

Unlike many other tumor sites, to date, there has not been robust data to demonstrate a large role for immunotherapy in patients with mCRPC. However, there are several potential ways to increase immunotherapy response with the goal of improving the outcomes of immunotherapy for prostate cancer: (i) combination therapy, (ii) immune modulation, (iii) biomarkers for improving patient selection.

Options for combination therapies:

1) Combination of immunotherapies: multiple vaccines, vaccine plus an immune checkpoint inhibitor, or an immunocytokine plus an immune checkpoint inhibitor. KEYNOTE-650 combining nivolumab plus ipilimumab is an example of improved efficacy among patients receiving combination therapy.

2) Combinations with therapies to capitalize on immunologic synergy: these studies assess the effect of the addition of other accepted treatments such enzalutamide, poly ADP ribose polymerase PARP inhibitors, radium-223, and docetaxel to immunotherapy regimens.

3) Given the changing microenvironment of prostate cancer across disease states, beginning combination immunotherapy earlier (castration-sensitive) may improve the immunotherapeutic benefit.

There are several options of immunomodulatory agents that target the tumor microenvironment to improve immunotherapy efficacy. Docetaxel has been proven to induce immunogenic modulations, such as increasing expression of ICAM-1, MUC-1, and MHC class 1 molecules.22 Additionally, tasquinimod is an immunomodulatory agent that blocks S100A9, a key regulatory molecule of myeloid cells. In a Phase II trial of 206 asymptomatic chemotherapy-naïve mCRPC patients randomized to tasquinimod vs placebo, men receiving tasquinimod had significantly improved disease progression (7.6 vs 3.3 months, p = 0.0042).23 Unfortunately, a Phase III trial assessing tasquinimod did not improve OS (21.3 for tasquinimod vs 24 months for placebo, HR 1.10, p=0.25), however, there was an improvement in radiographic PFS (7.0 months vs 4.4 months, HR 0.64, p = 0.001).24

Biomarkers continue to be an active area of research, not just for the selection of appropriate patients for immunotherapy, but also for other treatment regimens for advanced prostate cancer (ie. BRCA status for selecting patients for PARP inhibitors).

As follows is a summary of several of the current biomarkers as related to immunotherapy and prostate cancer (adapted from Maia and Hansen8):

current biomarkers as related to immunotherapy and prostate cancer

As follows is a summary of ongoing, recruiting phase III trial assessing immunotherapy in prostate cancer:

ongoing recruiting phase III trial assessing immunotherapy in prostate cancer

Conclusion 

To date, immunotherapy in prostate cancer has been less successful than other cancer types, with only Sipuleucel-T demonstrating an OS advantage of 4.1 months in a Phase III trial. Given the plethora of other treatment options, Sipuleucel-T is uncommonly used. However, with improved combination therapy, immunomodulation and biomarkers in addition to ongoing Phase III trials, there are additional assessments and results in upcoming that may improve the immunotherapy landscape and add to the armamentarium of treatment options for men with advanced prostate cancer.

Published Date: November 2019

Written by: Zachary Klaassen, MD, MSc
References: 1. Kantoff PW, Higano CS, Shore ND, et al. Sipuleucel-T immunotherapy for castration-resistant prostate cancer. N Engl J Med. 2010;363(5):411-422.
2. Ryan CJ, Smith MR, Fizazi K, et al. Abiraterone acetate plus prednisone versus placebo plus prednisone in chemotherapy-naive men with metastatic castration-resistant prostate cancer (COU-AA-302): final overall survival analysis of a randomised, double-blind, placebo-controlled phase 3 study. Lancet Oncol. 2015;16(2):152-160.
3. de Bono JS, Oudard S, Ozguroglu M, et al. Prednisone plus cabazitaxel or mitoxantrone for metastatic castration-resistant prostate cancer progressing after docetaxel treatment: a randomised open-label trial. Lancet. 2010;376(9747):1147-1154.
4. Parker C, Nilsson S, Heinrich D, et al. Alpha emitter radium-223 and survival in metastatic prostate cancer. N Engl J Med. 2013;369(3):213-223.
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16. Gulley JL, Borre M, Vogelzang NJ, et al. Phase III Trial of PROSTVAC in Asymptomatic or Minimally Symptomatic Metastatic Castration-Resistant Prostate Cancer. J Clin Oncol. 2019;37(13):1051-1061.
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19. Beer TM, Kwon ED, Drake CG, et al. Randomized, Double-Blind, Phase III Trial of Ipilimumab Versus Placebo in Asymptomatic or Minimally Symptomatic Patients With Metastatic Chemotherapy-Naive Castration-Resistant Prostate Cancer. J Clin Oncol. 2017;35(1):40-47.
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24. Sternberg C, Armstrong A, Pili R, et al. Randomized, Double-Blind, Placebo-Controlled Phase III Study of Tasquinimod in Men With Metastatic Castration-Resistant Prostate Cancer. J Clin Oncol. 2016;34(22):2636-2643.

The Role of Remote Interactions in Genitourinary Oncology: Implications for Practice Change in Light of the COVID-19 Pandemic

The rapid spread of Coronavirus Disease 2019 (COVID-19) caused by the novel severe acute respiratory syndrome corona virus-2 (SARS-CoV-2) has dramatically reshaped the structure of Western society, including on health care delivery.1 While care for patients with cancer has been prioritized in nearly every guideline and recommendation, data suggest that among patients with COVID-19, those with a history of cancer have significantly increased risk of severe outcomes.2 Further, patients most at risk of a severe SARS-CoV-2 phenotype are men and those of advanced age or comorbidity,1,3-6 demographics which mirror the patient population with genitourinary cancers.
Written by: Christopher J.D. Wallis, MD, PhD and Zachary Klaassen, MD, MSc
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  35. Metcalf M, Glazyrine V, Glavin K, et al. The Feasibility of a Health Care Application in the Treatment of Patients Undergoing Radical Cystectomy. The Journal of urology. 2019;201(5):902-908.
  36. Catto JWF, Khetrapal P, Ambler G, et al. Multidomain Quantitative Recovery Following Radical Cystectomy for Patients Within the Robot-assisted Radical Cystectomy with Intracorporeal Urinary Diversion Versus Open Radical Cystectomy Randomised Controlled Trial: The First 30 Patients. European urology. 2018;74(4):531-534.
  37. van Hout L, Bokkerink WJV, Ibelings MS, Vriens P. Perioperative monitoring of inguinal hernia patients with a smartphone application. Hernia. 2020;24(1):179-185.
  38. Raja JM, Elsakr C, Roman S, et al. Apple Watch, Wearables, and Heart Rhythm: where do we stand? Ann Transl Med. 2019;7(17):417.
  39. Krishnan N, Li B, Jacobs BL, et al. The Fate of Radical Cystectomy Patients after Hospital Discharge: Understanding the Black Box of the Pre-readmission Interval. Eur Urol Focus. 2018;4(5):711-717.
  40. Krishnan N, Liu X, Lavieri MS, et al. A Model to Optimize Followup Care and Reduce Hospital Readmissions after Radical Cystectomy. The Journal of urology. 2016;195(5):1362-1367.
  41. Cai S, Grubbs A, Makineni R, Kinosian B, Phibbs CS, Intrator O. Evaluation of the Cincinnati Veterans Affairs Medical Center Hospital-in-Home Program. J Am Geriatr Soc. 2018;66(7):1392-1398.
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  44. Breteler MJM, KleinJan E, Numan L, et al. Are current wireless monitoring systems capable of detecting adverse events in high-risk surgical patients? A descriptive study. Injury. 2019.
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  48. Salami AC, Barden GM, Castillo DL, et al. Establishment of a Regional Virtual Tumor Board Program to Improve the Process of Care for Patients With Hepatocellular Carcinoma. J Oncol Pract. 2015;11(1):e66-74.
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Prostate Cancer and Tumor Markers

The discovery of prostate-specific antigen (PSA) in the late 1970s and its widespread application and adoption in the 1980s and 1990s ushered in the prostate cancer screening and disease monitoring era. As the first tumor marker for prostate cancer, it is organ specific but not cancer specific.1 thus providing the opportunity for further tumor marker investigation. A potential biomarker must go through a rigorous vetting process from discovery → differentiation of case from control → ability to detect preclinical disease (defining a positive test) → indications for application and validation → cancer control studies.2 Secondary to the cost and time involved, biomarkers are rarely tested in large randomized controlled trials (RCTs). However, the development of the Prospective Randomized Open, Blinded Endpoint (PROBE) initiative for biomarker studies was designed to overcome spectrum and ascertainment bias and give guidance for validation studies.3 Biomarkers are typically evaluated based on their positive predictive value (probability that a positive test indicates the presence of disease) and negative predictive value (probability that a negative test indicates the absence of disease), entities that rely on the test’s specificity, sensitivity, and prevalence of the disease. This article will focus on briefly reviewing the clinical utility of several commonly used tumor markers associated with prostate cancer detection.

Blood

PSA
PSA is part of the kallikrein gene family located on chromosome 19 and functions as a serine protease, predominantly produced by prostate luminal cells. PSA in the serum is typically bound to proteins (~80% of PSA; complexed) or unbound (free PSA). The production of PSA is androgen dependent4 and in the absence of cancer varies with age,5 race,6, 7 and prostate volume.8 African-American men without prostate cancer have a higher PSA level compared to similar Caucasian men when assessed on a volume-to-volume ratio.9 Additionally, many studies have suggested that PSA in men with higher body mass index (BMI) have lower PSAs, a concept referred to as “hemodilution”:10 a greater plasma volume leading to lower hematocrit and PSA. Recent studies have provided further support for the hemodilution theory, in that only a fraction of lower PSA values in obese men are attributed to testosterone and dihydrotestosterone levels, with the remaining lower PSA explained presumably by hemodilution.11 The greatest contributor to elevated PSA is prostatic diseases, namely prostatitis, BPH and prostate cancer. Without question, the decrease in specificity associated with PSA and prostate cancer is an elevated PSA in men with prostatitis and/or BPH.

Free PSA (fPSA)
fPSA is PSA that is enzymatically inactive and non-complexed, making up 4-45% of total PSA;12 men with PSA from prostate cancer cells have a lower percentage of total PSA that is free, compared to those without prostate cancer.13 fPSA has FDA approval for men with a negative digital rectal examination (DRE) and total PSA level of 4-10 ng/mL, largely on the basis of a prospective study of men demonstrating a %fPSA (fPSA/total PSA) cutoff of 25% detecting 95% of prostate cancers, while avoiding 20% of biopsies.14 A generally acceptable cut-point ranges from 15-25%. Twenty years later, %fPSA is still used for clinically appropriate men, most commonly used in those with an elevated PSA and a negative prostate biopsy. In these men, studies have reported a 5% cancer under-detection rate and 21% cutoff for repeating prostate biopsy.15

Kallikreins
PSA, also known as human kallikrein 3 (hK3), is the most famous of the kallikreins, however, there are other kallikreins that have recently been explored as prostate cancer tumor markers. hK2 shares 80% amino acid homology with PSA, however, is weakly expressed in benign tissue and intensely expressed in prostate cancer tissue.16 Low-grade disease generally has low expression of hK2, whereas aggressive disease has high levels of expression.16 Recently, the hK2 kallikrein has been incorporated into a panel of kallikrein markers (total PSA, free PSA, intact PSA, and hK2, along with clinical information), commercially available as the 4KScore Test, used for calculating a patient’s percent risk for aggressive prostate cancer. First described in 2008, Vickers et al.17 tested the utility of the kallikrein panel in 740 men in the Swedish arm of the ERSPC screening trial. They found that adding free and intact PSA with hK2 to total PSA improved the clinical area under the curve (AUC) from 0.72 to 0.84. When the authors applied a 20% risk of prostate cancer as the threshold for biopsy, 424 (57%) of biopsies would have been avoided, missing 31 of 152 low-grade and 3 of 40 high-grade cancers.17 Since this study a decade ago, many studies have validated these findings, including among 6,129 men participating in the ProtecT study:18 the AUC for the four kallikreins was 0.719 (95%CI 0.704-0.734) vs 0.634 (95%CI 0.617-0.651, p<0.001) for PSA and age alone for any-grade cancer, and 0.820 (95%CI 0.802-0.838) vs 0.738 (95%CI 0.716-0.761) for high-grade prostate cancer. 

Prostate Health Index (phi)
The phi test combines total, free and [-2]proPSA into a single score for improving the accuracy of prostate cancer detection. In the seminal study leading to FDA approval, Catalona et al.19 assessed phi scores among 892 patients without prostate cancer and a PSA between 2-10 ng/mL. They found that an increasing phi score was associated with a 4.7-fold increased risk of prostate cancer and a 1.6-fold increased risk of Gleason score ≥ 4+3 disease at prostate biopsy. Furthermore, the phi score AUC exceeded that of %fPSA (0.72 vs 0.67) to discriminate high vs low-grade disease or negative biopsy. In a subsequent study, Loeb et al.20 confirmed the phi score’s ability to outperform total, free and [-2]proPSA for identifying clinically significant prostate cancer.

Urine

Prostate Cancer Antigen 3 (PCA3)
PCA3 is a long noncoding RNA shed into the urine that is not expressed outside the prostate and is associated with much higher expression in malignant than benign prostate tissue.21 Prior to collecting urine for a PCA3 test, a “rigorous” DRE is performed in order to enhance the sensitivity of the test. The commercial PCA3 score is reported as a ratio of urine PCA3 mRNA to urine PSA mRNA x 1000. The optimal cutoff is still debated, however in a contemporary comparative effectiveness review, Bradley et al.22 showed that a PCA3 threshold of 25 resulted in a sensitivity of 74% and specificity of 57% for a positive biopsy. This threshold led to FDA approval of the PCA3 test in 2012 among men with a prior negative prostate biopsy.

Since then, several groups have reported results of PCA3 in biopsy naïve men. In a retrospective review of 3,073 men undergoing initial biopsy, Chevli et al.23 found that the mean PCA3 was 27.2 for those without, and 52.5 for patients with prostate cancer. Prostate cancer was identified in 1,341 (43.6%) men; on multivariable analysis, PCA3 was associated with any (OR 3.0, 95%CI 2.5-3.6) and high-grade (OR 2.4, 95%CI 1.9-3.1) prostate cancer after adjusting for clinicopathologic variables. Furthermore, PCA3 outperformed PSA in the prediction of prostate cancer (AUC 0.697 vs 0.599, p<0.01) but did not for high-grade disease (AUC 0.682 vs 0.679, p=0.702).23

microRNAs (miRNAs)
miRNAs are small, noncoding single-stranded RNAs involved in the regulation of mRNA. Due to their short sequence (typically 19-22 nucleotides), miRNAs are highly stable in most body fluids (including urine) as they are resistant to RNase degradation.24 Several miRNAs have been implicated as potential biomarkers in prostate cancer diagnosis and management, including miRNA-141, miRNA-375, miRNA-221, miRNA-21, miRNA-182 and miRNA-187.25, 26 miR-187 detected in urine has been suggested as a candidate for improving the predictive value for a positive biopsy; a prediction model including serum PSA, urine PCA3, and miR-187 provided 88.6% sensitivity and 50% specificity (AUC 0.711, p = 0.001) for a positive biopsy.26 Ultimately, these miRNAs need to be further validated in terms of their ability to regulate various pathways important for prostate cancer management and their potential role as tumor markers.

Combining Tumor Markers

In an effort to improve the predictive accuracy of a positive biopsy, the last several years have seen a plethora of studies combining biomarkers to not only improve predictive accuracy above that offered by PSA, but also individual, newer biomarkers. As previously mentioned, the decrease in specificity associated with PSA and prostate cancer is secondary to an elevated PSA in men with prostatitis and/or BPH. The “perfect” biomarker (or combination) would delineate prostate cancer (and ultimately high-grade prostate cancer) from other benign entities.

Vedder et al.27 assessed the added value of %fPSA, PCA3, and 4KScore Test to the ERSPC prediction models among men in the Dutch arm of the ERSPC screening trial. Prostate cancer was detected in 119 of 708 men – adding %fPSA did not improve the predictive value of the risk calculators, however, the 4KScore discriminated better than PCA3 in univariate models (AUC 0.78 vs. 0.62; p=0.01). In the overall population, there was no statistically significant difference between the multivariable model with PCA3 (AUC 0.73) versus the model with the 4KScore (AUC 0.71; p=0.18). Among 127 men with a previous negative biopsy, Auprich et al.28 compared the performance of total PSA, %fPSA, PSA velocity (PSAV), and PCA3 at first, second and ≥ third repeat biopsy. At first repeat biopsy, PCA3 predicted prostate cancer best (AUC 0.80) compared with total PSA. A second repeat biopsy, %fPSA demonstrated the highest accuracy (AUC 0.82), and again at ≥ third repeat biopsy %fPSA demonstrated the highest accuracy (AUC 0.70).28 

This sampling of studies demonstrates that many combinations of biomarkers are being studied in an effort to improve detection of high-grade cancer and decrease the number of unnecessary biopsies. The next generation of biomarker combinations has and will continue to incorporate multi-parametric prostate MRI into predictive algorithms for clinically significant prostate cancer.29-31

Conclusions

For over four decades, research efforts have been directed towards improving the detection of prostate cancer and attempting to build on the predictive accuracy of the first prostate cancer tumor marker, PSA. With the United States Preventative Services Task Force’s 2012 recommendation for the urgent need to identify new screening efforts to better identify indolent versus aggressive disease, the last several years have seen a dramatic increase in prostate cancer biomarker options. As briefly highlighted, biomarker combinations studies have demonstrated improved predictive accuracy of positive biopsies; however, these combinations are far from perfect, are expensive and much work remains to be done. Furthermore, the specific indication (pre-biopsy, post-negative biopsy, active surveillance, etc) and a combination of tumor markers remain to be fully elucidated.

Published Date: April 16th, 2019
Written by: Zachary Klaassen, MD, MSc
References: 1. Partin AW, Carter HB, Chan DW, Epstein JI, Oesterling JE, Rock RC, et al. Prostate specific antigen in the staging of localized prostate cancer: influence of tumor differentiation, tumor volume and benign hyperplasia. J Urol. 1990;143:747-52.
2. Srivastava S. The early detection research network: 10-year outlook. Clin Chem. 2013;59:60-7.
3. Pepe MS, Feng Z, Janes H, Bossuyt PM, Potter JD. Pivotal evaluation of the accuracy of a biomarker used for classification or prediction: standards for study design. J Natl Cancer Inst. 2008;100:1432-8.
4. Henttu P, Liao SS, Vihko P. Androgens up-regulate the human prostate-specific antigen messenger ribonucleic acid (mRNA), but down-regulate the prostatic acid phosphatase mRNA in the LNCaP cell line. Endocrinology. 1992;130:766-72.
5. Partin AW, Criley SR, Subong EN, Zincke H, Walsh PC, Oesterling JE. Standard versus age-specific prostate specific antigen reference ranges among men with clinically localized prostate cancer: A pathological analysis. J Urol. 1996;155:1336-9.
6. Smith DS, Carvalhal GF, Mager DE, Bullock AD, Catalona WJ. Use of lower prostate specific antigen cutoffs for prostate cancer screening in black and white men. J Urol. 1998;160:1734-8.
7. Espaldon R, Kirby KA, Fung KZ, Hoffman RM, Powell AA, Freedland SJ, et al. Probability of an abnormal screening prostate-specific antigen result based on age, race, and prostate-specific antigen threshold. Urology. 2014;83:599-605.
8. Naya Y, Stamey TA, Cheli CD, Partin AW, Sokoll LJ, Chan DW, et al. Can volume measurement of the prostate enhance the performance of complexed prostate-specific antigen? Urology. 2002;60:36-41.
9. Fowler JE, Jr., Bigler SA, Kilambi NK, Land SA. Relationships between prostate-specific antigen and prostate volume in black and white men with benign prostate biopsies. Urology. 1999;53:1175-8.
10. Ohwaki K, Endo F, Muraishi O, Hiramatsu S, Yano E. Relationship between prostate-specific antigen and hematocrit: does hemodilution lead to lower PSA concentrations in men with a higher body mass index? Urology. 2010;75:648-52.
11. Klaassen Z, Howard LE, Moreira DM, Andriole GL, Jr., Terris MK, Freedland SJ. Association of Obesity-Related Hemodilution of Prostate-Specific Antigen, Dihydrotestosterone, and Testosterone. Prostate. 2017;77:466-70.
12. McCormack RT, Rittenhouse HG, Finlay JA, Sokoloff RL, Wang TJ, Wolfert RL, et al. Molecular forms of prostate-specific antigen and the human kallikrein gene family: a new era. Urology. 1995;45:729-44.
13. Catalona WJ, Beiser JA, Smith DS. Serum free prostate specific antigen and prostate specific antigen density measurements for predicting cancer in men with prior negative prostatic biopsies. J Urol. 1997;158:2162-7.
14. Catalona WJ, Partin AW, Slawin KM, Brawer MK, Flanigan RC, Patel A, et al. Use of the percentage of free prostate-specific antigen to enhance differentiation of prostate cancer from benign prostatic disease: a prospective multicenter clinical trial. JAMA. 1998;279:1542-7.
15. Stephan C, Lein M, Jung K, Schnorr D, Loening SA. Re: Editorial: can prostate specific antigen derivatives reduce the frequency of unnecessary prostate biopsies? J Urol. 1997;157:1371.
16. Darson MF, Pacelli A, Roche P, Rittenhouse HG, Wolfert RL, Saeid MS, et al. Human glandular kallikrein 2 expression in prostate adenocarcinoma and lymph node metastases. Urology. 1999;53:939-44.
17. Vickers AJ, Cronin AM, Aus G, Pihl CG, Becker C, Pettersson K, et al. A panel of kallikrein markers can reduce unnecessary biopsy for prostate cancer: data from the European Randomized Study of Prostate Cancer Screening in Goteborg, Sweden. BMC Med. 2008;6:19.
18. Bryant RJ, Sjoberg DD, Vickers AJ, Robinson MC, Kumar R, Marsden L, et al. Predicting high-grade cancer at ten-core prostate biopsy using four kallikrein markers measured in blood in the ProtecT study. J Natl Cancer Inst. 2015;107.
19. Catalona WJ, Partin AW, Sanda MG, Wei JT, Klee GG, Bangma CH, et al. A multicenter study of [-2]pro-prostate specific antigen combined with prostate specific antigen and free prostate specific antigen for prostate cancer detection in the 2.0 to 10.0 ng/ml prostate specific antigen range. J Urol. 2011;185:1650-5.
20. Loeb S, Sanda MG, Broyles DL, Shin SS, Bangma CH, Wei JT, et al. The prostate health index selectively identifies clinically significant prostate cancer. J Urol. 2015;193:1163-9.
21. de Kok JB, Verhaegh GW, Roelofs RW, Hessels D, Kiemeney LA, Aalders TW, et al. DD3(PCA3), a very sensitive and specific marker to detect prostate tumors. Cancer Res. 2002;62:2695-8.
22. Bradley LA, Palomaki GE, Gutman S, Samson D, Aronson N. Comparative effectiveness review: prostate cancer antigen 3 testing for the diagnosis and management of prostate cancer. J Urol. 2013;190:389-98.
23. Chevli KK, Duff M, Walter P, Yu C, Capuder B, Elshafei A, et al. Urinary PCA3 as a predictor of prostate cancer in a cohort of 3,073 men undergoing initial prostate biopsy. J Urol. 2014;191:1743-8.
24. Schwarzenbach H, Nishida N, Calin GA, Pantel K. Clinical relevance of circulating cell-free microRNAs in cancer. Nat Rev Clin Oncol. 2014;11:145-56.
25. Sharma N, Baruah MM. The microRNA signatures: aberrantly expressed miRNAs in prostate cancer. Clin Transl Oncol. 2018.
26. Casanova-Salas I, Rubio-Briones J, Calatrava A, Mancarella C, Masia E, Casanova J, et al. Identification of miR-187 and miR-182 as biomarkers of early diagnosis and prognosis in patients with prostate cancer treated with radical prostatectomy. J Urol. 2014;192:252-9.
27. Vedder MM, de Bekker-Grob EW, Lilja HG, Vickers AJ, van Leenders GJ, Steyerberg EW, et al. The added value of percentage of free to total prostate-specific antigen, PCA3, and a kallikrein panel to the ERSPC risk calculator for prostate cancer in prescreened men. Eur Urol. 2014;66:1109-15.
28. Auprich M, Augustin H, Budaus L, Kluth L, Mannweiler S, Shariat SF, et al. A comparative performance analysis of total prostate-specific antigen, percentage free prostate-specific antigen, prostate-specific antigen velocity and urinary prostate cancer gene 3 in the first, second and third repeat prostate biopsy. BJU Int. 2012;109:1627-35.
29. Johnston E, Pye H, Bonet-Carne E, Panagiotaki E, Patel D, Galazi M, et al. INNOVATE: A prospective cohort study combining serum and urinary biomarkers with novel diffusion-weighted magnetic resonance imaging for the prediction and characterization of prostate cancer. BMC Cancer. 2016;16:816.
30. Sciarra A, Panebianco V, Cattarino S, Busetto GM, De Berardinis E, Ciccariello M, et al. Multiparametric magnetic resonance imaging of the prostate can improve the predictive value of the urinary prostate cancer antigen 3 test in patients with elevated prostate-specific antigen levels and a previous negative biopsy. BJU Int. 2012;110:1661-5.
31. Perlis N, Al-Kasab T, Ahmad A, Goldberg E, Fadak K, Sayid R, et al. Defining a Cohort that May Not Require Repeat Prostate Biopsy Based on PCA3 Score and Magnetic Resonance Imaging: The Dual Negative Effect. J Urol. 2018;199:1182-7.

PARP Inhibitors in Prostate Cancer

Prostate cancer is a clinically heterogeneous disease with many patients having an indolent course requiring no interventions and others who either present with or progress to metastasis. While underlying dominant driving mutations are not widespread, there have been a number of key genomic mutations that have been consistently identified in prostate cancer patients, across the disease spectrum including gene fusion/chromosomal rearrangements (TMPRSS2-ERG), androgen receptor (AR) amplification, inactivation of tumor suppressor genes (PTEN/PI3-K/AKT/mTOR, TP53, Rb1) and oncogene activation (c-MYC, RAS-RAF).1
Written by: Christopher J.D. Wallis, MD, PhD and Zachary Klaassen, MD, MSc
References:
  1. Rubin MA, Maher CA, Chinnaiyan AM. Common gene rearrangements in prostate cancer. Journal of clinical oncology : official journal of the American Society of Clinical Oncology. 2011;29(27):3659-3668.
  2. Kunkel TA, Erie DA. DNA mismatch repair. Annu Rev Biochem. 2005;74:681-710.
  3. Pritchard CC, Mateo J, Walsh MF, et al. Inherited DNA-Repair Gene Mutations in Men with Metastatic Prostate Cancer. The New England journal of medicine. 2016;375(5):443-453.
  4. Castro E, Romero-Laorden N, Del Pozo A, et al. PROREPAIR-B: A Prospective Cohort Study of the Impact of Germline DNA Repair Mutations on the Outcomes of Patients With Metastatic Castration-Resistant Prostate Cancer. Journal of clinical oncology : official journal of the American Society of Clinical Oncology. 2019;37(6):490-503.
  5. Nicolosi P, Ledet E, Yang S, et al. Prevalence of Germline Variants in Prostate Cancer and Implications for Current Genetic Testing Guidelines. JAMA Oncol. 2019;5(4):523-528.
  6. Dantzer F, de La Rubia G, Menissier-De Murcia J, Hostomsky Z, de Murcia G, Schreiber V. Base excision repair is impaired in mammalian cells lacking Poly(ADP-ribose) polymerase-1. Biochemistry. 2000;39(25):7559-7569.
  7. McCabe N, Turner NC, Lord CJ, et al. Deficiency in the repair of DNA damage by homologous recombination and sensitivity to poly(ADP-ribose) polymerase inhibition. Cancer Res. 2006;66(16):8109-8115.
  8. Gudmundsdottir K, Ashworth A. The roles of BRCA1 and BRCA2 and associated proteins in the maintenance of genomic stability. Oncogene. 2006;25(43):5864-5874.
  9. Farmer H, McCabe N, Lord CJ, et al. Targeting the DNA repair defect in BRCA mutant cells as a therapeutic strategy. Nature. 2005;434(7035):917-921.
  10. Ashworth A. A synthetic lethal therapeutic approach: poly(ADP) ribose polymerase inhibitors for the treatment of cancers deficient in DNA double-strand break repair. J Clin Oncol. 2008;26(22):3785-3790.
  11. Fong PC, Boss DS, Yap TA, et al. Inhibition of poly(ADP-ribose) polymerase in tumors from BRCA mutation carriers. N Engl J Med. 2009;361(2):123-134.
  12. Mateo J, Carreira S, Sandhu S, et al. DNA-Repair Defects and Olaparib in Metastatic Prostate Cancer. The New England journal of medicine. 2015;373(18):1697-1708.
  13. Mateo J, Porta N, McGovern U, et al. TOPARP-B: A phase II randomized trial of the poly(ADP)-ribose polymerase (PARP) inhibitor olaparib for metastatic castration resistant prostate cancers (mCRPC) with DNA damage repair (DDR) alterations. J Clin Oncol. 2019;37(15_suppl):5005.
  14. de Bono J, Mateo J, Fizazi K, et al. Olaparib for Metastatic Castration-Resistant Prostate Cancer. The New England journal of medicine. 2020.
  15. de Wit R, de Bono J, Sternberg CN, et al. Cabazitaxel versus Abiraterone or Enzalutamide in Metastatic Prostate Cancer. The New England journal of medicine. 2019;381(26):2506-2518.
  16. Clarke N, Wiechno P, Alekseev B, et al. Olaparib combined with abiraterone in patients with metastatic castration-resistant prostate cancer: a randomised, double-blind, placebo-controlled, phase 2 trial. The lancet oncology. 2018;19(7):975-986.
  17. Abida W, Bryce AH, Vogelzang N, et al. Preliminary Results From TRITON2: A Phase II Study of Rucaparib in Patients with mCRPC Associated with Homologous Recombination Repair Gene Alterations. Ann Oncol. 2018;29(suppl_8):viii271.
  18. Smith MR, Sandhu S, Kelly WK, et al. Phase II study of niraparib in patients with metastatic castration-resistant prostate cancer (mCRPC) and biallelic DNA-repair gene defects (DRD): Preliminary results of GALAHAD. J Clin Oncol. 2019;37(7_suppl):202.
  19. Hussain M, Daignault-Newton S, Twardowski PW, et al. Targeting Androgen Receptor and DNA Repair in Metastatic Castration-Resistant Prostate Cancer: Results From NCI 9012. Journal of clinical oncology : official journal of the American Society of Clinical Oncology. 2018;36(10):991-999.
  20. Hussain M, Carducci MA, Slovin S, et al. Targeting DNA repair with combination veliparib (ABT-888) and temozolomide in patients with metastatic castration-resistant prostate cancer. Invest New Drugs. 2014;32(5):904-912.
  21. Yu EY, Massard C, Retz M, et al. Keynote-365 cohort a: Pembrolizumab (pembro) plus olaparib in docetaxel-pretreated patients (pts) with metastatic castrate-resistant prostate cancer (mCRPC). J Clin Oncol. 2019;37(7_suppl):145.

Epidemiology and Etiology of Prostate Cancer

In 2018 in the United States, there will be an estimated 164,690 new cases of prostate cancer (19% of all male cancer incident cases, 1st) and an estimated 29,430 prostate cancer mortalities (9% of all male cancer deaths, 2nd only to lung/bronchus cancer).1 Over the last four decades, there was a spike in prostate cancer incidence in the late 1980’s/early 1990’s secondary to the widespread adoption of prostate-specific antigen (PSA) testing for the asymptomatic detection of prostate cancer.2 Since 1991, prostate cancer mortality has decreased by more than 40% due to a combination of increased PSA screening and improvement in treatment.3 This article will discuss the epidemiology of prostate cancer, as well as focus on several important etiologic risk factors associated with the disease.

Epidemiology

Incidence
For the last 30+ years, prostate cancer has been the most common noncutaneous malignancy among men in the United States, with 1 in 7 men being diagnosed with the disease.4 Similar to the United States, prostate cancer is the second most commonly diagnosed malignancy among men worldwide, with 1.1 million new cases diagnosed per year.5 In developed countries, the age-standardized rate (ASR) of prostate cancer incidence is 69.5 per 100,000 compared to 14.5 per 100,000 in developing countries.5 Crude differences in incidence between developed and developing countries are likely secondary to poor use of screening6 and lower life expectancies in developing countries.

Mortality
Among all men in the United States, 1 in 38 men will die from prostate cancer.4 Prostate cancer ranks as the leading cause of cancer death globally, with the highest mortality rates noted in the Caribbean and Southern/Middle Africa.5 Furthermore, the ASR for mortality in developed countries is 10.0 per 100,000 compared to 6.6 per 100,000 in developing countries.5 Many hypotheses have been considered as to the decline in mortality seen in the United States after 1991, with the most commonly accepted (in addition to utilization of screening) being an increase in aggressive curative treatment of prostate cancer diagnosed in the 1980s.7,8

A Global Perspective
The incidence and epidemiology from a global perspective is much different than what may typically be seen in the United States and Europe. For example, in India the incidence of prostate cancer is a fraction (1.7-5.3 per 100,000) of other first world countries (North America: 83.2-173.7 per 100,000),6 but secondary to the sheer size of the population (1.2 billion) the crude prevalence of prostate cancer is on par with countries such as the United States, UK, France, and Italy. Despite greater awareness of prostate cancer screening, data from India suggest that 4% of patients <50 years of age present with metastatic disease. Among worldwide prostate cancer incidence, 14% of cases are diagnosed within the Asia-Pacific region, with a wide variation of incidence rates across the Asian-Pacific countries. In Latin American countries, prostate cancer represents 28% of all incidence cancers (highest) and 13% of all cancer mortalities (second after lung cancer). Specifically, in Trinidad and Tobago, Guyana and Barbados, the incidence is 3-4x that of the United States. Particularly in Cuba, the mortality rates continue to increase, despite greater adoption of screening.  The incidence of prostate cancer in the Middle East is higher than the Asian countries, specifically in Lebanon (37.2 per 100,000), Jordan (15.3 per 100,000), and Palestine (15.2 per 100,000). A closer look at the demographics at presentation among Middle Eastern men shows that 25% present with metastatic disease, with rates as high as 58% among men from Iraq. There are several hypotheses for the shift in incidence and prevalence of prostate cancer among non-North America/European countries, including (1) an increased awareness of prostate cancer leading to greater utilization of PSA testing, and (2) adoption of a more “Western” diet/lifestyle and less the traditional Indian/Asian/Mediterranean diet, particularly in the urban centers.

Unfortunately, a greater burden of disease among non-North American/European regions has presented several problems:

  1. A wide variation in incidence/prevalence across countries in these regions, particularly in Asia-Pacific and Latin America
  2. Huge discrepancies in quality and access to care between the private and public sector
  3. Poor access to newer standards of care, leading to high rates of surgical castration and limited access to radiation therapy (ie. for treatment of bone metastases)
  4. Limited organized cancer registries, thus grossly underestimating the true incidence and prevalence of prostate cancer
Age and Family History
Age is an established risk factor for prostate cancer, as men <40 years of age are highly unlikely to be diagnosed with prostate cancer, whereas men >70 years of age have a 1 in 8 chance of prostate cancer diagnosis.1 In a population-based analysis of more than 200,000 patients, increasing age was associated with higher 15-year cancer-specific mortality (CSM) rates: 2.3% for men diagnosed ≤50 years of age, 3.4% for men 51-60 years of age, 4.6% for men 61-70 years of age, and 6.3% for men ≥71 years of age.9

A family history of prostate cancer is also strongly predictive of a prostate cancer diagnosis. To be considered hereditary prostate cancer, a family must have three affected generations, three first-degree relatives affected, or two relatives diagnosed prior to age 55.10 Men with one first-degree relative previously diagnosed with prostate cancer have a risk of a prostate cancer diagnosis that is 2-3x that of individuals with no family history.11 Data on 65,179 white men from the PLCO cancer screening trial showed that men with a family history of prostate cancer had a significantly higher incidence of prostate cancer (16.9% vs 10.8%, p<0.01) and higher cancer-specific mortality (0.56% vs 0.37%, p<0.01).12

Race
Both prostate cancer incidence and mortality have been shown to be significantly related to race. African-Americans and Jamaicans of African descent have the highest incidence of prostate cancer in the world.1 Despite decreases in mortality since the 1990s among all races, death rates of African Americans are still 2.4x higher than Caucasian patients.13 Several studies have assessed possible reasons for this discrepancy. In an ad hoc analysis of the REDUCE trial, African American men had greater non-compliance with study-mandated2 and 4-year prostate biopsies, despite having greater prostate cancer risk (at 2-year biopsy),14 suggesting that population-level estimates of the excess prostate cancer burden in African American men may underestimate the degree of prostate cancer disparity. Gene expression assessment of prostate cancer specimens has noted numerous differentially expressed genes between African American and white patients, suggesting that there may be racial differences in androgen biosynthesis and metabolism.15 However, studies in mCRPC patients assessing clinical response to the potent anti-androgen abiraterone have not demonstrated racial differences when prospectively evaluated.16

The incidence of prostate cancer among races other than African-American and Caucasians is lower, including men of Asian descent living in the United States, although their incidence of prostate cancer is higher than those living within continental Asia.17 Interestingly, men moving from developing countries to high prostate cancer incidence countries demonstrate a shift in prostate cancer risk similar to that of their new country of residence.18 Ultimately, the relative components of genetics, socioeconomic factors, cultural, and environmental factors associated with racial differences observed are poorly understood.   

Trends
There has been a significant drop in prostate cancer incidence in the last decade (~10% annually per year from 2010-2014), likely secondary to a decrease in PSA testing after the US Preventative Services Task Force (USPSTF) Grade D recommendation for screening of men older than 75 years of age (2008) and subsequently all men (2012) due to concern for overdiagnosis and overtreatment.13,19 Following the USPSTF recommendations, an analysis of the National Cancer Database suggested that in the month after the recommendation, incident prostate cancer diagnoses decreased by 1,363 cases, followed by a drop of 164 cases per month thereafter for the first year (28% decrease in incident cases).20 There has been considerable debate as to whether patients present with the more advanced disease since the USPSTF recommendations with no general consensus.21 Recently, the USPSTF changed their recommendation for PSA screening among men aged 55-69 years of age to a Grade C, suggesting that men in this age bracket should undergo periodic PSA-based screening for prostate cancer based on a decision after discussion regarding the potential benefits and harms of screening with their clinician.22

Etiology and Risk Factors

Diet and Obesity
Initial evidence that diet and lifestyle may have a role in prostate cancer epidemiological outcomes was provided by ecological studies which demonstrated that men in Western countries had higher rates of prostate cancer than developing/non-Western countries.6 To strengthen this possible association, subsequent studies demonstrated that men from non-Western countries migrating to Western countries adopted similar lifestyle and prostate cancer risk as those in Western countries.23 Nonetheless, several prospective studies since these ecologic descriptions assessing self-reported dietary patterns of healthy foods and the risk of prostate cancer have failed to show an association with diet and risk of prostate cancer.24,25 Epidemiological evidence suggesting that statins reduce the risk of advanced stage prostate cancer suggests a possible role of cholesterol and prostate cancer risk.26 Regardless, the complexity of the Western diet and the association/interaction with healthier lifestyles are limitations to understanding how diet influences prostate cancer risk.  

Obesity has become an epidemic in the United States, and observational studies have suggested a modest increase in the risk of prostate cancer among obese individuals.27,28 The pathophysiology between obesity and prostate cancer is likely secondary to higher levels of estradiol, insulin, and free IGF-1 levels, as well as lower free testosterone and adiponectin levels.29 However, a clear pathophysiological explanation between obesity and prostate cancer is still uncertain and may be associated with lower serum PSA and larger prostates leading to fewer prostate biopsies.30   

Inflammation
Chronic inflammation has been implicated in the development of several cancers and may also be associated with prostate cancer. Possible etiologic factors suggested include: infectious agents, dietary carcinogens, hormonal imbalances, as well as physical and chronic trauma.31 As a result, intra-prostatic inflammation may lead to DNA damage, epithelial proliferation, cellular turnover, and angiogenesis.31 In men part of the placebo arm of the Prostate Cancer Prevention Trial (PCPT), those with at least one biopsy core of inflammation had an odds ratio (OR) of 1.78 (95%CI 1.04-3.06) for prostate cancer compared to men with no cores of inflammation.32 Furthermore, this association was even higher when considering a high-grade prostate cancer diagnosis (OR 2.24, 95%CI 1.06-4.71).32

Medications
As mentioned, there has been emerging evidence that HMG-CoA reductase inhibitors (statins) may be associated with a lower risk of prostate cancer mortality following diagnosis.33 Although there have been disparate results for the beneficial nature of statins and prostate cancer, a recent meta-analysis from observational studies of nearly 1 million patients noted that both post- and pre-diagnosis use of statins are beneficial for both overall survival (HR 0.81, 95%CI 0.72-0.91) and cancer-specific survival (HR 0.77, 95%CI 0.66-0.85).34 Nonetheless, the exact role statins play in prostate carcinogenesis/protection is still widely debated.

Similar optimism with statins has been associated with metformin use and prostate cancer outcomes. Among patients with diabetes, metformin has been associated with a significant dose-dependent benefit for both prostate cancer-specific (HR 0.76, 95%CI 0.64-0.89 for each additional six months of metformin use) and all-cause mortality.35 In a systematic review and meta-analysis of observational studies assessing clinical outcomes of patients with prostate cancer and metformin, medication use was marginally associated with a reduction in risk of biochemical recurrence (HR 0.82, 95%CI 0.67-1.01), but not associated with metastasis, prostate-cancer mortality or all-cause mortality.36

Genetics
Prostate cancer is known to have an extraordinarily complex genetic makeup, including somatic copy number alterations, point mutations, structural rearrangements, and changes in chromosomal number.37 It is estimated that 5-10% of all prostate cancers may be caused by dominantly inherited genetic factors.11 These include, but are not limited to HPC1, HPC2, HPC20, HPCX, PCAP, and CAPB.38 More famously are the mutations associated with BRCA1 and BRCA2 and the associated increase in the risk of clinically significant prostate cancer, and prostate cancer-specific mortality among men with screen-detected prostate cancer.39-41 Recent research has evaluated epigenetic markers for prostate cancer such as miRNA. The first report of miRNA and prostate cancer was reported in 2007,42 and since then many reports have implicated over 30 unique miRNAs and prostate carcinogenesis.

Conclusions

The epidemiology and etiology of prostate cancer are complex and multi-factorial. Prostate cancer remains a malignancy spanning the spectrum of localized/indolent disease to de novo advanced disease that is ultimately fatal. Although there are accepted differences in race and geography, the ultimate interplay between sociodemographic factors, environmental/lifestyle factors, and genetic differences remains to be fully elucidated.

Published Date: April 16th, 2019
Written by: Zachary Klaassen, MD, MSc
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