This study by the MGH group reported outcomes of 204 pediatric patients with chordomas treated by surgery and proton radiotherapy (PRT). Forty-seven patients (23%) received PRT, and 157 (77%) received comboRT to a median total dose of 76.7 Gy (RBE). At a median follow-up of 10 years, 56 patients recurred. Median OS and PFS were 26 and 25 years, with 5-, 10-, and 20-year OS and PFS rates of 84% and 74%, 78% and 69%, and 64% and 64%, respectively. Side effects included 166 patients (80%) with mild/moderate acute toxicities, 24 (12%) patients with late toxicities, and 4 (2%) developed secondary radiation-related malignancies. The authors concluded that results of this largest cohort of skull base chordomas demonstrated high-dose PRT following surgical resection is effective with low rates of late toxicity.