Radiation therapy plus bicalutamide improves long-term survival for men with recurring prostate cancer after initial surgery, according to a study published in the New England Journal of Medicine (2017;376:417-428).
Men with prostate cancer who have undergone radical prostatectomy and have cancer recurrence may require salvage radiation therapy. The survival effects of salvage radiation therapy in combination with antiandrogen therapy for such patients is relatively unknown and in need of further investigation.
William U Shipley, MD, Massachusetts General Hospital in Boston, and colleagues conducted a double-blind, placebo-controlled study to analyze the impact of antiandrogen therapy with radiation therapy on recurring prostate cancer control and overall survival (OS). A total of 760 patients were sampled who had undergone surgery for localized cancer and demonstrated recurrence between 1998 and 2003. Patients were assigned to undergo further radiation therapy (6.5 weeks) followed by either antiandrogen therapy (150 mg/day of bicalutamide for 24 months) or daily placebo tablets for the same length of time. The primary endpoint was rate of OS.
After a follow-up of 12 years, OS was significantly higher in the bicalutamide group (76.3%) compared with the placebo group (71.3%; hazard ration for death, 0.77; 95% confidence interval, 0.59 to 0.99; P = .04). Fewer patients in the bicalutamide group died of prostate cancer-specific causes compared with patients in the placebo group (5.8% vs 13.4%, respectively). Cumulative incidence of metastatic prostate cancer after 12 years was lower in the bicalutamide group compared with the placebo group (14.5% vs 23.0%, respectively). Additionally, researchers noted similar adverse events for patients in both groups, with the exception of an increased rate of gynecomastia in patients in the bicalutamide group (69.7%).
Authors of the study concluded that 24 months of antiandrogen therapy with daily bicalutamide in combination with salvage radiation therapy results in significantly higher rates of long-term OS, lower risk of metastatic cancer, and lower risk of mortality compared with radiation therapy plus placebo for men with recurring prostate cancer.
Authors noted that bicalutamide did not impact survival rates of patients with prostate-specific antigen levels below 0.7 or patients with Gleason scores below 7 when the trial began.
