A persistent PSA level following radical prostatectomy for prostate cancer is associated with a worse prognosis

Abstract

Waiting for at least 3 months to assess the prostate-specific antigen (PSA) level after radical prostatectomy may minimize overtreatment in some patients according to the results of a study published in JAMA Oncology.¹

A conventional assessment of the PSA level typically occurs 1.5–2.0 months after radical prostatectomy, but data on the serum half-life of total PSA after radical prostatectomy suggest that it may take longer for clearance of PSA from the serum, particularly in patients with higher PSA levels before surgery.²

Investigators in the current study evaluated how long to monitor PSA after radical prostatectomy to accurately document persistent PSA. They also looked at whether an increasing level of PSA predicts worse outcomes.

Using databases from two academic health centers, investigators identified 43,298 patients with T1N0M0 to T3N0M0 prostate cancer who were treated with radical prostatectomy between 1992 and 2020: 30,461 of the patients were included in the initial discovery cohort, and 12,837 were included in a subsequent validation cohort.

The study evaluated whether a significant interaction existed between a PSA level greater than 20 ng/mL versus 20 ng/mL or less before radical prostatectomy and a persistent PSA level versus undetectable PSA after radical prostatectomy with respect to prostate cancer-specific mortality (PCSM) risk and all-cause mortality (ACM) risk. The analysis was adjusted for all known prostate cancer prognostic factors.

Investigators found that among patients with a persistent PSA level after radical prostatectomy, a presurgery PSA level greater than 20 ng/mL versus 20 ng/mL or less was significantly associated with reduced ACM risk and PCSM risk. The association remained after adjusting for the prostate gland volume. The PCSM finding was confirmed in the validation cohort.

Investigators said the “counterintuitive” finding may be explained by a higher proportion of patients with a preradical prostatectomy PSA level greater than 20 ng/mL versus 20 ng/mL or less who would have been observed to have reached an undetectable PSA level with longer PSA assessment.

The study also found that patients with an increasing persistent PSA level after radical prostatectomy had a significantly increased ACM risk (adjusted hazard ratio [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).

The senior author of the study, Anthony D’Amico, MD, a professor of radiation oncology at Harvard Medical School and chief of genitourinary radiation oncology at the Brigham and Women’s Hospital and Dana-Farber Brigham Cancer Center in Boston, Massachusetts, underscores the importance of waiting for 3 months after surgery before ascertaining whether the PSA level is persistent. “If the PSA level is still detectable at three months, repeating another PSA within the next month would also be advised,” he says. “If stable or rising, then salvage treatment at that point would be appropriate. However, if the value is continuing to decline, continued PSA monitoring would be advised.”