Jimenez RB, Hickey S, DePauw N, et al. - Researchers examined whether proton beam radiation therapy (RT) is safe and efficacious for patients with breast cancer who require regional nodal irradiation. Eligible patients were those with nonmetastatic breast cancer who required postoperative RT to the breast/chest wall and regional lymphatics and were considered suboptimal candidates for conventional RT were eligible for participation. From 2011 to 2016, 70 patients completed RT. During median follow-up of 55 months (range, 17 to 82 months). Among 69 evaluable patients [median age: 45 years (range, 24 to 70 years)], 68 (99%) received systemic chemotherapy, 50 (72%) underwent immediate reconstruction. Comprehensive coverage was achieved with a median dose of 49.7 Gy to the chest wall/breast (relative biological effectiveness) and with a median dose of 48.8 Gy to the internal mammary nodes (relative biological effectiveness). Outcomes revealed low toxicity rates and similar rates of disease control in relation to proton beam RT for breast cancer vs historical data of conventional RT. They observed no early cardiac changes, which justifies conducting randomized studies comparing proton beam RT with standard RT.