A review article by the Japanese researchers about the particle radiotherapy in comparison to photon-based radiation for prostate cancer. Due to a lack of direct evidence, the superiority of particle beam RT over photon beam RT for prostate cancer has not been confirmed in terms of the rates of overall survival or bRFS as end-points. The available data reviewed showed that treatment outcomes with particle beam RT, and the adverse events induced by particle beam RT have consistently been acceptable.

Although long-term observation in a large-scale randomized study is necessary for the most accurate evaluation of the efficacy of particle beam RT for prostate cancer, but particle beam RT seems a reasonable RT method delivering a high RT dose safely. The Japanese radiation oncology society is carrying out a multi-institutional prospective study of IMRT, PBT and CIRT, and registration of all studies will be completed by April 2020.