1: Addition of antiandrogen treatment to salvage radiation therapy increases survival
A double-blind, placebo-controlled trial published in the New England Journal of Medicine shows that addition of the antiandrogen bicalutamide to salvage radiotherapy increases overall and prostate cancer specific survival.
Following prostatectomy, 760 men who had T2 or T3 confirmed disease were randomised to receive radiation therapy in combination with 24 months of daily bicalutamide or placebo control. With a median follow up of 13 years, the 12 year actuarial overall survival rate was 76.3% in the bicalutamide group compared to 71.3% in the placebo control group (HR 0.77, p=0.04). In addition, comparing men in the bicalutamide vs control group at 12 years, the rate of prostate specific death was 5.8% vs 13.4% (p<0.001) and the cumulative incidence of metastatic prostate cancer was 14.5% vs 23% (p=0.005). While late adverse effects associated with radiotherapy were similar between the two groups, there was a higher rate of gynecomastia in the bicalutamide group (69.7%) compared to the control group (10.9%).
Of note, since this was a blinded study men did not receive prophylactic radiation prior to beginning antiandrogen treatment, as normally occurs in practice. This trial started in 1998 and bicalutamide has since been superseded by other gonadotrophin-releasing hormone (GnRH) analogues such as goserelin or leuprorelin. While it is predicted that these newer treatments will also increase survival effects of salvage radiation, we look forward to hearing about results from the ongoing RADICALS trial which is addressing this question.