Long-term analysis of RTOG 0415 trial of conventional fractionated versus hypofractionated radiotherapy for low-risk prostate cancer

The phase 3 noninferiority trial NRG Oncology RTOG 0415 compares conventional fractionation (C-RT; 73.8 Gy in 41 fractions) versus hypofractionation (H=RT 70 Gy in 28 fractions) in patients with low-risk prostate cancer. Long-term results of the trial have now been published. The 12-year disease-free survival (DFS) rate was 56.1% for C-RT and 61.8% for H-RT (p for noninferiority <0.001). The 12-year biochemical failure (BF) rate was 17.0% for C-RT and 9.9% for H-RT (HR 0.55; 95% CI 0.39-0.78). There were no significant differences between the groups in incidences of late grade ≥ 3 GI/GU adverse events. The authors conclude that H-RT is noninferior to C-RT in terms of DFS and results in lower rates of BF.