This study by the Jacksonville group reported the incidence of brainstem toxicity after proton therapy. 163 patients with skull base chordoma or chondrosarcoma treated to a median total dose of 73.8 GyRBE were analyzed. With a median follow-up of 4 years, the 5-year cumulative incidence of grade ≥2 brainstem injury was 1.3%. There was one grade 2, one grade 3, and no grade 4 or 5 events, with all patients recovering function with medical management.