ORLANDO, FL, USA (UroToday.com) - Dr. Brian Chapin, MD, from M.D. Anderson Cancer Center discussed the need for evaluation of an integrated strategy, including cytoreductive prostatectomy or radiation therapy, for treatment of newly diagnosed hormone-sensitive metastatic prostate cancer. Historically, local therapy is seen as means of curative treatment. Dr. Chapin argued that local therapy of the primary tumor can be seen as a key strategy in multimodal therapy rather than as curative therapy, alone.
The rationale behind the use of local therapy for primary tumor is as follows:
- First, control of the primary tumor is linked to longer survival in men with metastatic prostate cancer. A recent study by Culp, et. al in Eur Urol 2014, based on SEER, showed that definitive local treatment (radical prostatectomy or radiation therapy) in men with metastatic prostate cancer improved both overall survival and disease-specific survival compared to patients who did not undergo localized surgery or radiation therapy.
- Second, symptomatic progression is reduced with treatment of the primary disease in men with progressive metastatic disease. Metastatic prostate cancer patients who underwent no local therapy had up to 54% late local complications as compared to 47% in the EBRT group and 20% in the radical prostatectomy group.
- Third, molecularly “lethal prostate cancer” persists in the primary tumor despite systemic therapy. Dr. Chapin discussed the ‘cancer self-seeding’ hypothesis, which suggests that cells from the metastatic site can return to the primary site, which can promote progression. Thus, definitive treatment of the primary tumor may favorably alter tumor biology.
Therefore, Dr. Chapin hypothesized that controlling of the primary tumor may improve outcomes and survival of men with metastatic prostate cancer. Control of the primary tumor needs to occur in the setting of multimodal therapy. Neoadjuvant therapy prior to radical prostatectomy in men with high-risk prostate cancer does not increase surgical morbidity. Up to 90% continence is possible in these patients. Dr. Chapin argued in favor of early local treatment rather than seeing patients develop severe local symptoms and performing palliative surgeries. He showed data on palliative cystoprostatectomy, which helped relieve local symptoms in 30/38 patients at the cost of 13% rectal injury and a 24% need for subsequent surgery.
Dr. Chapin discussed two current trials investigating the role of ADT+/-radiation in M1 prostate cancer. Both HORRAD and STAMPEDE are accruing patients, with primary outcome being overall survival and secondary outcomes being biochemical progression and QOL. Finally, he highlighted the prospective multicenter randomized phase II trial of best systemic therapy (BST) or BST plus definitive treatment of the primary tumor (surgery or radiation therapy) in metastatic prostate cancer (NCT01751438) that is being led from M.D. Anderson. It is hoped that this study will identify the benefit of local control in newly diagnosed, hormone-sensitive metastatic prostate cancer patients.
Presented by Brian F. Chapin, MD at the 2015 Genitourinary Cancers Symposium - "Integrating Biology Into Patient-Centric Care" - February 26 - 28, 2015 - Rosen Shingle Creek - Orlando, Florida USA
University of Texas M.D. Anderson Cancer Center, Houston, TX USA
Reported by Mohammed Haseebuddin, MD, medical writer for UroToday.com