Stratification of Patient Risk Based on Prostate-Specific Antigen Doubling Time After Radical Retropubic Prostatectomy

Abstract

To assess the risk of local recurrence, systemic progression, and death from cancer among patients who experience biochemical relapse after radical retropubic prostatectomy and to stratify those patients by prostate-specific antigen (PSA) doubling time (DT). We identified patients who experienced biochemical recurrence (defined as a PSA level < or =0.4 ng/mL) after radical prostatectomy from January 1, 1990, to December 31, 1999, for prostate adenocarcinoma. The PSA-DT was calculated by log linear regression using all PSA values within 2 years of biochemical recurrence. Local recurrence- and systemic progression- free survival and cancer-specific survival were estimated using the Kaplan-Meier method and analyzed by the log-rank test and Cox models. Biochemical recurrence was noted in 1521 (27%) of 5533 men during the follow-up period. Of the 1064 patients with a calculable PSA-DT, 322 (30%) had a PSA-DT of less than 1 year, 357 (34%) had a PSA-DT of 1 to 9.9 years, and 385 (36%) had a PSA-DT of 10 years or more. Patients with a PSA-DT of 10 years or more were less likely to have a higher preoperative PSA level, Gleason score, advanced pathologic stage, and seminal vesicle invasion. Patients with a PSA-DT of 10 years or more were at low risk of local recurrence (hazard ratio [HR], 0.09; 95% confidence interval [CI], 0.06-0.14; compared with patients with a PSA-DT of <1 year), systemic progression (HR, 0.05; 95% CI, 0.02-0.13), or death from cancer (HR, 0.15; 95% CI, 0.05-0.43). Prostate-specific antigen DT is an independent predictor of clinical disease recurrence and mortality after surgical biochemical failure. Risk stratification into high-, intermediate-, and low-risk categories based on the PSA-DT provides helpful clinical information and assists in the development of salvage therapy trials.