This study from Japan reported 45 cases of localized prostate cancer treated with real-time image-gated spot-scanning proton therapy (RGPT) where 3 to 4 pure gold fiducial markers were inserted in the prostate. The total dose of 70 GyRBE was delivered in 30 fractions with 3 or 4 fields. With a median follow-up of 63 months, this study reported early AE (≥grade 2) in 4 cases (8.9%), the overall 5-year bRFS of 88.9%, and late grade 2 rectal bleeding in 8 cases (17.8%). The authors concluded that this RGPT for prostate cancer with 1.5-mm markers and 3- or 4- fields was as safe as conventional proton therapy in early AE, and its efficacy was comparable with previous studies.