Adding Anti-Androgens to Late Salvage RT May Improve PCa Outcomes

In a study, the increased risk for overall and cancer-specific mortality associated with late vs early salvage radiation therapy was eliminated by the concomitant use of anti-androgen therapy.

Concomitant use of anti-androgen therapy (AAT) may improve outcomes among men who receive late salvage radiation therapy (sRT) for biochemical recurrence of prostate cancer after radical prostatectomy, data presented at the 22nd annual meeting of the Society of Urologic Oncology suggest.

“Our study is the first study to demonstrate that poorer outcomes associated with late sRT in men with recurrent prostate cancer after radical prostatectomy may be successfully rescued by use of concomitant AAT,” Akshay Sood, MD, of the Vattikuti Center for Outcomes Research, Analytics, and Evaluation at Henry Ford Hospital in Detroit, Michigan, and colleagues concluded in a poster presentation.

Their study included 670 men who participated in the RTOG 9601 trial. They stratified the patients into 4 treatment groups: early sRT (pre-salvage PSA level less than 0.7 ng/mL) with or without concomitant AAT and late sRT (pre-salvage PSA level 0.7 ng/mL or higher) with or without concomitant AAT. The median follow-up duration was 14.7 years. The investigators defined AAT as 24 months of bicalutamide.

The 15-year overall mortality rates in the groups having early sRT alone, early sRT with AAT, late sRT alone, and late sRT with AAT were 22.9%, 22.8%, 40.1% and 22.9%, respectively, the investigators reported. The 15-year prostate cancer-specific mortality rates were 12.1%, 3.9%, 22.7%, and 8.0%, respectively. The 15-year metastasis rates were 18.8%, 14.6%, 35.9%, and 19.5%, respectively.

In time-varying analysis, late vs early sRT was significantly associated with a 1.49-fold increased risk for overall mortality, but the addition of concomitant AAT to late sRT eliminated the increased risk. Dr Sood and colleagues found similar results when analyzing the risks for prostate cancer-specific mortality and metastatic progression.

Reference

Sood A, Keeley J, Jeong W, et al. Anti-androgen therapy overcomes the time-delay in initiation of salvage radiation therapy and rescues the oncological outcomes in men with recurrent prostate cancer after radical prostatectomy: A post-hoc analysis of the RTOG 9601 trial data. Presented at the 22nd annual meeting of the Society of Urologic Oncology, December 1-3, 2021. Poster 138.