Three-Year Outcomes With Hypofractionated Versus Conventionally Fractionated Whole-Breast Irradiation: Results of a Randomized, Noninferiority Clinical Trial

PurposeThe adoption of hypofractionated whole-breast irradiation (HF-WBI) remains low, in part because of concerns regarding its safety when used with a tumor bed boost or in patients who have received chemotherapy or have large breast size. To address this, we conducted a randomized, multicenter trial to compare conventionally fractionated whole-breast irradiation (CF-WBI; 50 Gy/25 fx + 10 to 14 Gy/5 to 7 fx) with HF-WBI (42.56 Gy/16 fx + 10 to 12.5 Gy/4 to 5 fx).Patients and MethodsFrom 2011 to 2014, 287 women with stage 0 to II breast cancer were randomly assigned to CF-WBI or HF-WBI, stratified by chemotherapy, margin status, cosmesis, and breast size. The trial was designed to test the hypothesis that HF-WBI is not inferior to CF-WBI with regard to the proportion of patients with adverse cosmetic outcome 3 years after radiation, assessed using the Breast Cancer Treatment Outcomes Scale. Secondary outcomes included photographically assessed cosmesis scored by a three-physician panel and local recurren...