This study evaluated 70 patients among who 63 patients (91%) had left-sided breast cancer, two had bilateral breast cancer, and five had right-sided breast cancer; 65 (94%) had stage II to III breast cancer; 68 (99%) received systemic chemotherapy; 50 (72%) underwent immediate reconstruction.

With the median follow-up of 55 months, the study reported that among 62 surviving patients, the 5-year rates for locoregional failure and overall survival were 1.5% and 91%. One patient developed grade 2 RP, and none developed grade 3 RP. No grade 4 toxicities occurred. The authors concluded that PBT for breast cancer has low toxicity rates and similar rates of disease control compared with historical data of conventional RT.