Time to PSA Nadir and the Risk of Death from Prostate Cancer following Radiation and Androgen Deprivation Therapy

4 Background: Whether the time to PSA nadir (TTN) has differential prognostic value in men who reach an undetectable versus detectable PSA nadir remains unknown. Methods: Two-hundred and four men from a prospective randomized controlled trial (RCT) involving radiation therapy with or without 6 months of androgen deprivation therapy (ADT) in unfavorable risk CaP at academic or community based centers in Massachusetts, enrolled between 1995 and 2001. Adjusted hazard ratios (AHR) of the risk of CaP-specific mortality (PCSM) calculated using Fine and Gray competing risk regression. Results: After a median follow-up of 18.17 years, 160 men died; 30 (18.75%) of CaP. Amongst men with a PSA nadir ≥ 0.2 ng/ml, a TTN < median (12 months) was significantly associated with an increased PCSM-risk versus the median or more (AHR 5.07, 95% CI 2.10-12.23, p