Gleason score and the risk of cause-specific and overall mortality following radiation with or without 6 months of androgen deprivation therapy for men with unfavorable-risk prostate cancer.

Abstract

171 Background: We evaluated whether a differential impact of adding 6 months of androgen deprivation (ADT) to radiation therapy (RT) on all-cause, prostate cancer-specific, and other-cause mortality (ACM, PCSM, OCM) in men with unfavorable-risk PC exists within Gleason score (GS) subgroups. Methods: Individual patient data from 743 men with unfavorable-risk PC from two randomized ADT trials were utilized. Competing risks and Cox regression were used to determine whether adding 6 months of ADT to RT significantly impacted PCSM, OCM and ACM within GS subgroups. Results: Men with GS 9,10 versus ≤ 8 were significantly more likely to be over 75 (23.3% versus 12.7%;p = 0.03). At a median follow-up of 11.9 and 11.8 years in the 683 and 60 patients with GS ≤ 8 and GS 9,10, 315 (46.1%) and 44 had died (73.1%), respectively. ADT in men with GS ≤ 8 was associated with significantly decreased ACM (Adjusted hazard ratio (AHR) 0.66; 95% confidence interval (CI): 0.52-0.82; p < 0.001) and PCSM (0.43; 0.28-0.66; p < 0.001) but was not associated with OCM (0.90; 0.68-1.17; p = 0.43). Among men with GS 9,10 PC, ADT significantly reduced PCSM (0.33; 0.11-0.99; p = 0.048) but not ACM (0.79; 0.38-1.61; p = 0.51) and increased OCM (2.16; 0.81-5.79; p = 0.12) resulting in opposite effects of ADT on OCM by GS subgroup (Table) such that the relative AHR of OCM in GS 9,10 versus ≤ 8 was nearly significantly increased (2.42; 0.87-6.71; p = 0.09). Conclusions: While ADT reduced PCSM for all men, survival was not prolonged in men with GS 9,10 due to ADT-driven increased OCM. This supports the hypothesis that older men with significant comorbidity may not experience prolonged survival when ADT is added to RT. [Table: see text]