Acute Toxicities of Proton Craniospinal Irradiation in Pediatric Medulloblastoma: A Pediatric Proton/Photon Consortium Registry (PPCR) Study.

Purpose: Medulloblastoma is one of the most common malignant brain tumors in children, and 75% of patients achieve long-term survival. There are limited studies reporting acute toxicity for pediatric patients receiving proton therapy for craniospinal irradiation (CSI) in medulloblastoma, and these are limited by their retrospective nature, modest cohort sizes, and lack of a comparator group. Materials and Methods: We analyzed data from the Pediatric Proton/Photon Consortium Registry. Patients with a diagnosis of medulloblastoma, receiving CSI with doses of either 23.4 Gy or 36 to 39.6 Gy, and with toxicity data at baseline and completion of treatment, were identified for inclusion. Results: A total of 272 patients were included for analysis. All patients received proton therapy. The median age of patients was 8 years (range 3-22 years), and 67.6% were male. Most patients were of good performance status with eastern cooperative oncology group (ECOG) 0 or 1, 36.8% and 31.6%, respectively. In total, 68.8% of patients had classic medulloblastoma; 76.8% had M0 disease; and 62.9% of patients had standard-risk disease.Acute toxicities were reported as grade 1 or higher. The most common toxicities occurring during treatment were skin (90.3%), gastrointestinal (71.6%), hematological (54.9%), and mouth (32.0%). Toxicity rates were lower than in the published literature. All patients completed treatment. Conclusion: Our findings suggest that proton CSI has an acceptable degree of acute toxicity in the treatment of pediatric medulloblastoma. Future studies would benefit from toxicity grading, toxicity timing, and a photon comparator group.