SIU 2017: The Comparison of Prognoses between Radiotherapy and Radical Prostatectomy in Patients with High Risk Localized or Locally Advanced Prostate Cancer Treated with Neoadjuvant Hormonal Therapy

Lisbon, Portugal ( Patients with high-risk prostate cancer (PSA >= 20, Gleason score >= 8, or cT2-4) are typically offered radical prostatectomy or EBRT + ADT (recommended for 2 years). However, there are no prospective studies comparing these treatment options.

In this study, the authors compare the prognosis of patients who received either RP or EBRT (+ median 3.6 months of neoadjuvant ADT). Over an 11 year period, 255 patients undergoing either RP (172) or EBRT (83) were included in this study. They were retrospectively evaluated using chart review. Primary outcome was biochemical recurrence (BCR) – defined as PSA 2 > nadir value in the EBRT group, or PSA > 0.2 in RP group. Other outcomes included local recurrence in the pelvis (LC), development of metastases, clinical painful symptom progression (CPSP), castration resistant prostate cancer (CRPC), and overall survival (OS).

The authors acknowledge that the two groups were different at baseline in terms of initial PSA, age, nadir PSA, PSA level at baseline. They were also different in terms of the number that went on to adjuvant hormonal therapy, development of BCR, and time to adjuvant HT. However, despite the difference in terms of their starting characteristics, survival analysis demonstrated no significant difference in any of the outcomes: median time to BCR, local recurrence, metastases, CPSP, CRPC, and OS.

However, there are obviously some significant limitations that preclude any strong conclusions.
1) Unclear from methodology whether RT patients received full course of ADT recommended (2 years)
2) Baseline characteristics were not provided, but the differences between the two groups makes comparisons moot. They are two different populations.
3) It is not made clear what secondary therapies each group received prior to CRPC and death. When they progressed, did they get chemotherapy, abiraterone, enzalutamide? These may affect outcomes.
4) Subset analysis or propensity matched analysis may have been helpful to better compare the groups.

Of note, there is general consensus that single modality therapy is insufficient for high risk prostate cancer. As such, there are already numerous trials ongoing that are addressing the role of multimodal therapy, including multimodal neoadjuvant therapy. Therefore, this question of surgery vs. EBRT alone may be a moot point.

Speaker(s): Jae Young Joung, South Korea

Institution(s): Center for Prostate Cancer, National Cancer Center, South Korea

Written by: Thenappan Chandrasekar, MD, Clinical Fellow, University of Toronto, twitter: @tchandra_uromd, at the 37th Congress of Société Internationale d’Urologie - October 19-22, 2017- Lisbon, Portugal