This study reported the clinical outcomes and toxicity rates after PBSPT CSI for 71 children and adolescents and young adults (C-AYAs) with CNS tumors. Medulloblastoma (n = 42: 59%) and ependymoma (n = 8; 11%) were the most common histologies. After a median follow-up of 24.5 months, the estimated 2-year local control, distant control, and overall survival were 86.3%, 80.5%, and 84.7%, respectively. Late grade ≥3 toxicity-free rate was 92.6% at 2 years. The authors concluded that excellent tumor control with low toxicity rates was observed in C-AYAs with brain tumors treated with CSI using PBSPT.