The following is a summary of “Prostate-Specific Antigen Level at the Time of Salvage Therapy After Radical Prostatectomy for Prostate Cancer and the Risk of Death,” published in the May 2023 issue of Oncology by Tilki, et al.

For a study, researchers determined if there was a threshold prostate-specific antigen (PSA) level above which initiating salvage radiation therapy (sRT) after PSA failure is associated with increased all-cause mortality (ACM)-risk in men with at most one high-risk factor (i.e., pT3/4 or prostatectomy [p] Gleason score 8-10) for prostate cancer.

A multinational database of 25,551 patients with pT2-4N0 or NXM0 prostate cancer evaluated the association between initiating sRT above a prespecified PSA level and increased ACM-risk. Multivariable Cox regression analysis was performed, adjusting for age at and year of radical prostatectomy, established prostate cancer prognostic factors, institution, and the time-dependent use of androgen deprivation therapy. The prespecified PSA levels ranged from 0.10 ng/mL to 0.50 ng/mL in 0.05 ng/mL increments.

After a median follow-up of 6.00 years, patients who received sRT at a PSA level >0.25 ng/mL had a significantly higher ACM-risk (adjusted hazard ratio [AHR], 1.49; 95% CI, 1.11 to 2.00; P = .008) compared to men who received sRT when the PSA was ≤0.25 ng/mL. This increased ACM-risk was significant for all PSA cutpoints up to 0.50 ng/mL but not for cutpoints below 0.25 ng/mL.

Initiating sRT above a PSA level of 0.25 ng/mL in men with at most one high-risk factor is associated with increased ACM-risk. The study suggested that delaying sRT beyond a PSA level of 0.25 ng/mL may have negative consequences and that the threshold should be considered when making treatment decisions.