(HealthDay News) — Among men with intermediate-risk prostate cancer, the addition of external beam therapy (EBT) to transperineal interstitial permanent brachytherapy (B) does not improve 5-year progression-free survival, according to a study presented at the annual meeting of the American Society for Radiation Oncology, held from Sept. 25 to 28 in Boston.
Bradley R. Prestidge, MD, from the DePaul Medical Center in Norfolk, Va., and colleagues randomized men with prostate cancer to receive 45 Gy partial pelvis EBT + B or B alone. Five hundred eighty-eight men were randomized (287 EBT + B eligible and 292 B eligible); patients were followed for a median of 6.7 years.
The researchers found that 5-year progression-free survival was 85% for the EBT + B arm and 86% for the B arm at the fifth interim analysis of 443 patients with 5 years of follow-up (hazard ratio, 1.02; futility P = 0.0006). The Data Monitoring Committee recommended early release for the initial reporting of the primary end point. Similar acute overall ≥ grade 3 toxicity was seen (8% for EBT + B and B). Overall ≥ grade 3 late toxicity was 12 and 7% for EBT + B and B, respectively.
“These findings suggest that many men with intermediate risk prostate cancer can be well managed with seed implant alone and do not require the addition of external beam radiation,” Prestidge said in a statement.