This study by the MGH group reported clinical outcomes of 204 pediatric patients with base of skull (BOS) chordomas treated by surgery and RT including forty-seven (23%) received protonRT, and 157 (77%) received comboRT. At a median follow-up of 10 years, 56 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%) who developed secondary radiation-related malignancies.