Hypofractionated volumetric‐modulated arc therapy for breast cancer: A propensity‐score‐weighted comparison of radiation‐related toxicity

We assessed the clinical benefit of combining volumetric‐modulated arc therapy (VMAT) and hypofractionated radiotherapy (HF‐RT) considering the incidence of radiation‐related toxicities. After a retrospective review for breast cancer patients treated with adjuvant RT between 2005 and 2017, a total of 4209 patients treated with three‐dimensional conventional fractionation (CF‐3D, 50.4 Gy/28 fractions) and 1540 patients treated with HF‐RT (768 received HF‐3D; 772, HF‐VMAT; 40 Gy/15 fractions) were included. A total of 2229 patients (38.8%) received regional node irradiation (RNI): 1642 (39.0%), 167 (21.7%) and 420 (54.4%) received RNI via CF‐3D, HF‐3D and HF‐VMAT, respectively. Acute/subacute and late toxicities were evaluated. Propensity scores were calculated via logistic regression. Grade 2+ acute/subacute toxicities was the highest in CF‐3D group (15.0%, 2.6% and 1.6% in CF‐3D, HF‐3D and HF‐VMAT, respectively; P