An increasing prostate-specific antigen (PSA) level in patients with prostate cancer is commonly associated with the improved performance of prostate-specific membrane antigen positron emission tomography, as well as insurance approval. As a result, some physicians will delay salvage radiation therapy (sRT) after radical prostatectomy following PSA failure.
However, for patients with at most 1 high-risk factor (such as pT3/4 or a prostatectomy Gleason score of 8-10), it is unknown if initiating sRT above a certain PSA level is associated with increased risk of all-cause mortality (ACM). A recent study explored this relationship.
Through a multinational database of 22,551 patients with pT2-4N0 or NXM0 prostate cancer, the researchers used multivariable Cox regression analysis to determine if an increase in ACM risk existed when sRT was delivered above a prespecified PSA level beginning at 0.10 ng/mL, and in increasing 0.05 increments up to 0.50 ng/mL, versus at or below that level. The model was adjusted based on patient age at the year of radical prostatectomy, established prostate cancer prognostic factors, institution, and time-dependent use of androgen deprivation therapy.
At a median follow-up of 6 years, patients who received sRT at a PSA level >0.25 ng/mL had a significantly higher ACM risk (adjusted hazard ratio, 1.49; 95% CI, 1.11-2.00; P=.008) compared with patients who received sRT when their PSA level was ≤0.25 mg/mL. The elevated ACM risk remained significant for all PSA cutoffs up to 0.50 ng/mL, but it was not significant at PSA cutoff values less than 0.25 ng/mL.
Patients with prostate cancer with at most 1 high-risk factor were found to have a higher ACM risk associated with initiation of sRT above a PSA level of 0.25 ng/mL.