Duration of the anti-androgen in men undergoing 6 months of an LHRH agonist and radiation therapy for unfavorable-risk prostate cancer and the risk of death.

Abstract

Whether adding a first-generation anti-androgen (AA) to a luteinizing hormone-releasing hormone agonist in the radiotherapeutic management of unfavorable-risk prostate cancer (PC) reduces the risk of all-cause and PC-specific mortality (ACM and PCSM) among men within differing comorbidity subgroups is unknown. Between 1995 and 2001, 206 men with unfavorable-risk PC were enrolled in a randomized trial comparing radiation with or without 6 months of androgen-deprivation therapy (ADT). Partial AA use (median: 4.2 months) occurred in 29 of the 102 men randomized to ADT. Cox, and Fine and Gray's regressions were used to evaluate the impact of full versus partial AA use on PCSM and ACM-risk within comorbidity subgroups. After a median follow-up of 16.62 years, 156 men died. In men with moderate to severe comorbidity increasing death was observed as treatment transitioned from no to partial to full ADT (P=0.02) with an increased ACM-risk with full versus partial AA use (adjusted hazard ratio (AHR), 2.25 (95% confidence interval (CI), 0.94-5.41); P=0.07); whereas only 1 and no PC deaths occurred in men receiving a partial versus full AA course, respectively. Among men with no or minimal comorbidity there was no decrease in ACM (AHR, 0.97 (95% CI, 0.49-1.91); P=0.92) or PCSM-risk (AHR 0.39 (95% CI 0.07-52.18); P=0.28) in comparing full versus partial AA use. Increasing AA use by 2 months does not appear to impact survival in men with localized unfavorable-risk PC and no or minimal comorbidity, but may shorten survival in men with moderate to severe comorbidity, raising concern regarding in whom and for how long the AA should be prescribed.