Persistent Prostate-Specific Antigen Following Radical Prostatectomy for Prostate Cancer and Mortality Risk

Importance: Whether the conventional 1.5-month to 2.0-month time interval following radical prostatectomy (RP) for prostate cancer (PC) is sufficient to accurately document a persistent prostate-specific antigen (PSA) remains unanswered. Objective: To evaluate the time necessary to accurately document a persistent PSA level after RP. Design, Setting, and Participants: This cohort study evaluated whether a significant interaction existed between (1) a pre-RP PSA level greater than 20 ng/mL vs 20 ng/mL or less and (2) persistent PSA vs undetectable PSA after RP on PC-specific mortality (PCSM) risk and all-cause mortality (ACM) risk, adjusting for known PC prognostic factors, age at RP, year of RP, and the time-dependent use of post-RP radiation therapy (RT) and androgen deprivation therapy (ADT). Whether an increasing persistent PSA level was associated with a worse prognosis was also investigated. Patients with T1N0M0 to T3N0M0 PC treated with RP between 1992 and 2020 at 2 academic centers were included. Follow-up data were collected until November 2023. Data were analyzed from July 2024 to January 2025. Exposure: RP. Main Outcomes and Measures: Adjusted hazard ratio (aHR) of ACM and PCSM risk. Results: Of 30 461 patients included in the discovery cohort, the median (IQR) age was 64 (59-68) years; of 12 837 patients included in the validation cohort, the median (IQR) age was 59 (54-64) years. Compared with patients with undetectable PSA, among patients with persistent PSA, a pre-RP PSA level greater than 20 ng/mL vs 20 ng/mL or less was significantly associated with reduced ACM risk (aHR, 0.69; 95% CI, 0.51-0.91; P = .01; P for interaction < .001) and PCSM risk (aHR, 0.41; 95% CI, 0.25-0.66; P < .001; P for interaction = .02). This result remained after adjustment for prostate volume and was confirmed in the validation cohort for PCSM risk and may represent a higher proportion of patients with a pre-RP PSA greater than 20 ng/mL vs 20 ng/mL or less who could have reached an undetectable PSA level if additional time for PSA assessment occurred before initiating post-RP therapy for presumed persistent PSA. Notably, there was more frequent and a shorter median time to post-RP RT plus ADT or ADT use in patients with a pre-RP PSA greater than 20 ng/mL (244 of 446 [54.7%] at a median [IQR] of 2.68 [1.51-4.40] months) vs 20 ng/mL or less (338 of 972 [34.8%] at a median [IQR] of 3.30 [2.00-5.39] months). These treatment times were shorter than the times to an undetectable PSA in observed patients (median [IQR] of 2.96 [1.84-3.29] months vs 3.37 [2.35-4.09] months, respectively). Increasing persistent PSA level was associated with an increased ACM risk (aHR, 1.14; 95% CI, 1.04-1.24; P = .004) and PCSM risk (aHR, 1.27; 95% CI, 1.12-1.45; P < .001). Conclusions and Relevance: PSA level assessed for at least 3 months after RP may minimize overtreatment, and in this study, a higher persistent PSA level was associated with a worse prognosis.