This study from Japan compared the clinical outcomes of IMRT (n=96) and PBT (n=510) for prostate cancer. With a median follow-up of 82 months, the 7-year rates of biochemical relapse-free survival (bRFS) and disease-free survival (DFS) rates were significantly higher with PBT: 95.1% for PBT vs 89.9% for IMRT (P = 0.0271) and 93.1% for PBT vs 85.0% for IMRT (P = 0.0019). In the matching analysis where 94 patients were assigned to both groups, the 7-year bRFS and DFS rates were 98.9% for PBT vs 89.7% for IMRT (P = 0.023) and 93.4% for PBT vs 84.6% for IMRT (P = 0.022). In the subgroup analysis of intermediate-risk patients, the PBT group showed a significantly higher 7-year bRFS rate (98.3% for PBT vs 90.5% for IMRT; P = 0.007).