This case-matched study analyzed 260 prostate cancer patients including 65 treated with PBT and 195 IMRT. At a median follow-up of 59 months, biochemical failure (BF), local failure (LF), regional failure (RF), distant failure (DF), and mortality rates were 45% (n=29), 2% (n=1), 9% (n=6), 9% (n=6), and 2% (n=1) for PBT, and 41% (n=80), 3% (n=5), 7% (n=13), 9% (n=18), and 5% (n=9) for IMRT (all p>0.05).

RT modality was not significantly associated with BF (all p>0.05), nor with LF (p=0.82), RF (p=0.11), DF (p=0.36), or all-cause mortality (p=0.69). Patterns of failure were qualitatively similar between cohorts (DF: bone, retroperitoneal nodes, lung).

This study concluded that PBT yielded similar long-term disease-related outcomes and patterns of failure to IMRT in the post-prostatectomy setting.