Timing of Prostate-specific Antigen Nadir After Radical Prostatectomy and Risk of Biochemical Recurrence

ObjectiveTo evaluate the association between the prostate-specific antigen (PSA) nadir level and the time to nadir (TTN) with biochemical recurrence (BCR) risk after radical prostatectomy (RP) in the Shared Equal-Access Research Cancer Hospital (SEARCH) database.Materials and methodsThis is a retrospective analysis of 1939 men from the SEARCH database treated with RP between 1998 and 2015 with available ultrasensitive PSA nadir within 1-6 months after RP. Uni- and multivariable analyses of PSA nadir and TTN with time from nadir to BCR were performed with Cox models (adjusted for demographics, tumor features, and preoperative PSA).ResultsAmong men with an undetectable PSA nadir, the TTN was unrelated to BCR (1.0-2.9 vs 3-6 months: hazard ratio [HR] 0.86, P = .46). Regardless of TTN, men with detectable nadir had an increased risk of BCR (TTN of 3-6 months: HR 1.81, P = .024; TTN of 1.0-2.99 months: HR 3.75, P