Role of Pelvic Radiation in Management of Non-Metastatic Pathological Node-Positive Prostate Cancer: A Single Institution Experience

Abstract

Pathological T2-4 N1 M0 prostate cancer (Pca) has a heterogeneous natural history. So far, only one randomized control trial has established the current standard of care of immediate androgen deprivation (ADT) after prostatectomy and lymph node dissection. The role of pelvic radiation (RT) for this cohort of patients remains unknown. The purpose of this study is to perform a retrospective review of our institutional experience to provide much-needed information that may improve the outcome of these very high-risk patients.We identified patients with pT2-4 N1 M0 disease treated in our institution from 2006 to 2016. We reviewed ADT and RT records in addition to patient and disease characteristics. Kaplan-Meier analyses were utilized to evaluate overall survival (OS) and progression-free survival (PFS, defined as either biochemical or clinical evidence of disease recurrence).We identified a total of 94 patients with pT2-4N1M0 Pca with patient demographic and disease characteristics shown in the table. A total of 72 patients had postoperative RT with a median follow-up of 85.9 months (range 15 to 175 months). Among patients receiving RT, 54/72 (75%) received ADT concurrently (median duration of 24 months, range 4 -36 months). The median time from prostatectomy to RT initiation was 6 months (range 3-90 months). RT of 7 patients was initiated after PSA progression. For patients without RT, 15/22 (68%) received ADT (median duration of 24 months, range 3 to 96 months); the median follow-up was 91 months (range 9 to 164 months). The estimated 5-year OS for patients with RT and without RT were 100% and 85.7%, respectively (P = 0.04). The estimated 5-year PFS for patients with RT and without RT were 80.9% and 62.8%, respectively (P = 0.19). Among patients who received ADT, the estimated 5-year PFS was 82.3% with RT and 63.8% without RT, respectively (P = 0.26).For a select group of patients with pT2-4N1M0 Pca, postoperative pelvic RT in combination with ADT appeared to have prolonged OS. Further investigation to stratify this group of patients, and ultimately prospective clinical trials to establish the effectiveness of combined pelvic RT and systemic treatment is needed for this cohort of high-risk patients.