To assess the utility of kinetics for ultrasensitive prostate-specific antigen (uPSA) assays to identify men who are at risk of developing high-risk recurrent prostate cancer [prostate-specific antigen doubling time (PSADT) < 9 months] after radical prostatectomy. Previous studies demonstrate that a PSADT < 9 months after radical prostatectomy is associated with prostate cancer-specific mortality. Conventionally, PSADT has been calculated after biochemical failure (PSA > or = 2 0.2 ng/mL).
A review of the Shared Equal Access Regional Cancer Hospital database from 1988-2008 was performed to identify men with biochemical failure after radical prostatectomy and > or = 2 uPSA values before failure (PSA > or = 2 0.2 ng/mL) as well as > or = 2 2 values after failure to calculate PSADT. These patients were stratified into low-risk (PSADT > or = 2 9 months) and high-risk (PSADT < 9 months) cohorts. The following uPSA kinetics were analyzed for their ability to predict low- and high-risk cohorts: time to first detectable uPSA, time from uPSA to biochemical failure, uPSA velocity, uPSADT, uPSA exponential rise, and uPSA fluctuations.
The analysis included 89 low- and 26 high-risk men. Time to first detectable uPSA was inversely associated with the high-risk cohort (OR 0.96, 95% CI 0.92-0.99, P = .02) and characterized by a high sensitivity and negative predictive value at a threshold of 2 years after surgery. Other measures of uPSA kinetics showed no association with PSADT.
Time to first detectable uPSA identifies men with low-risk recurrence prostate cancer. Patients with an undetectable uPSA 2 years after surgery are unlikely to develop PSADT < 9 months after biochemical failure.