Can PSA Levels Before Salvage Radiotherapy Predict Outcomes in Men With Prostate Cancer?
Posted: Wednesday, June 3, 2020
According to a secondary analysis of the RTOG 9601 trial published in JAMA Oncology, patients with prostate cancer and low prostate-specific antigen (PSA) levels who received antiandrogen treatment after salvage radiotherapy did not appear to derive any survival benefit. In addition, patients may be at an increased risk of developing other medical conditions. Robert T. Dess, MD, of the University of Michigan, Ann Arbor, and colleagues recommended that patients and health-care professionals consider these findings prior to initiating such treatment.
“We showed that a patient’s PSA level can serve as both a prognostic and predictive biomarker that can help us determine who will benefit from hormone therapy and who may be harmed by it,” stated coauthor Daniel E. Spratt, MD, in a University of Michigan press release.
This analysis aggregated data from 760 patients with biochemically recurrent prostate cancer from the RTOG 9601 double-blind, placebo-controlled randomized clinical trial. To be enrolled, patients were required to have T2 disease with a positive surgical margin or T3 disease after undergoing a radical prostatectomy, and a PSA level between 0.2 and 4.0 ng/mL prior to salvage radiotherapy. Each participant received salvage radiotherapy, however, some received high-dose nonsteroidal antiandrogen (bicalutamide) treatment for 2 years.
Compared with the placebo group, men with a PSA level above 1.5 ng/mL had a significant improvement in overall survival following bicalutamide treatment (P = .01), as well as a decreased risk of distant metastasis (P = .02). However, the difference in overall survival between men with a PSA level between 0.2 and 0.6 ng/mL who received bicalutamide treatment and the placebo group was not statistically significant (P = .46). In fact, the hazard of other-cause mortality was increased twofold in men with a PSA level between 0.2 and 0.6 ng/mL who underwent antiandrogen therapy. Such patients were also at an increased risk of grades 3 to 5 cardiac and neurologic events (P = .05).
Disclosure: For full disclosures of the study authors, visit jamanetwork.com.
