82 patients received PBT and their adverse events (AEs) were recorded prospectively at each institution. Median follow-up was 8.1 months. Median dose was 50.4 Gy in 28 fractions. 90% patients received a lumpectomy bed boost and 83% patients received regional nodal irradiation. Six patients (7.3%) experienced grade 3 AEs (5 with dermatitis, 5 with breast pain). Body mass index (BMI) was associated with grade 3 dermatitis (P = .015). Fifty-eight patients (70.7%) experienced grade ≥2 dermatitis.
The authors concluded that PBT including RNI after BCS is well-tolerated. Elevated BMI is associated with grade 3 dermatitis.