In this issue of JAMA Oncology, Baumann et al1 present a large single-institution retrospective analysis of proton- vs photon-based radiotherapy specifically for patients receiving concurrent chemotherapy for 11 types of locally advanced cancers. Patients undergoing proton therapy overall had significantly fewer grade 3 toxic effects requiring hospitalization at 90 days, as well as fewer grade 2 toxic effects at 90 days and a smaller decline in performance status during treatment.