BERKELEY, CA (UroToday.com) - Approximately one third of patients who undergo prostate biopsy are diagnosed with prostate cancer (PCa).
Actually, given the practice of widespread screening, this proportion does not vary greatly, being slightly higher for positive digital rectal exam (DRE) and elevated prostate-specific antigen (PSA) and somewhat lower for low PSA and negative DRE. PSA derivatives show heterogeneous improvement in PCa diagnosis accuracy among studies, and their capacity of identifying most aggressive cancers is controversial.
Exploring PSA derivatives as criteria for prostate biopsy in a prospective population-based outpatient clinical setting, PSA velocity resulted in more biopsies, 65 (36.1%), with low predictive positive value (PPV) 32.3%. Even associating positive DRE, PPV increased to only 43.9%, conflicting with current practice guidelines which recommend biopsy on the basis of high PSA velocity even in the absence of other indications such as an elevated PSA or a positive DRE. At the same time, this modest work indicates some trends: better PCa diagnosis accuracy for free/total PSA ratio and identification of most aggressive tumors utilizing PSA density.
While for each one of the criteria multiple cut-off ranges are to be tested in large prospective population studies, in recent times, the real value of PSA velocity has been put in check  and in the same vein, we recently showed no impact on PCa diagnosis after PSA decrease.
Simply put, a PSA decrease (even to a considered normal range) does not reflect lower PCa incidence on prostate biopsy and neither does a PSA increase necessarily accurately predict cancer diagnosis, putting in doubt the worth of PSA kinetics on PCa diagnosis.
Further studies are warranted to shed light on this scenario, and new tools are needed to improve the accuracy of prostate cancer detection. In the meantime, no one isolated criterion for prostate biopsy indication is indisputably finer, and all the criteria of PSA derivatives are considered complementary and useful predictors of cancer risk. Additionally, a positive DRE increases their PPV.
- Reis LO, Zani EL, Alonso JC, Simões FA, Rejowski RF, Ferreira U. [Does the criterion for prostate biopsy indication impact its accuracy? A prospective population-based outpatient clinical setting study]. Actas Urol Esp. 2011 Jan;35(1):10-4. Epub 2011 Jan 5. Spanish.
- Vickers AJ, Till C, Tangen CM, Lilja H, Thompson IM. An Empirical Evaluation of Guidelines on Prostate-specific Antigen Velocity in Prostate Cancer Detection. J Natl Cancer Inst. 2011 Feb 24. PMID: 21350221, doi: 10.1093/jnci/djr028 [Epub ahead of print]
- Stopiglia RM, Ferreira U, Silva MM Jr, Matheus WE, Denardi F, Reis LO. Prostate specific antigen decrease and prostate cancer diagnosis: antibiotic versus placebo prospective randomized clinical trial. J Urol. 2010 Mar;183(3):940-4. Epub 2010 Jan 20.
Leonardo Oliveira Reis, MD, MSc as part of Beyond the Abstract on UroToday.com. This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.
Dr. Leonardo Oliveira Reis, M.D., M.Sc.
Assistant Professor at Division of Urologic Oncology
School of Medical Sciences
University of Campinas, UNICAMP, Brazil