Hypo Versus Conventional Fractionation in Reconstructed-Breast Cancer Mastectomy Patients

This study is a multicenter, randomized, phase 3 clinical trial. For breast cancer patients who underwent breast reconstruction after mastectomy, the hypofractionation radiotherapy group (experimental group) and the conventional fractionation radiotherapy group (control group) were divided 1:1 and compared to reveal the non-inferiority with hypofractionation in terms of major complication rate. I. Primary Objective * To show the non-inferiority of major complication rate in reconstructed-breast between the hypofractionation radiotherapy group (experimental group) and the conventional fractionation radiotherapy group (control group) at 2 years after radiation therapy. * The main complications are defined at those requiring hospitalization or surgery among complications. II. Secondary Objective: * Comparison of other side effects between the two groups. * Comparison of complication rate stratified by reconstruction timing and type of reconstruction * Immediate implant-based reconstruction * Immediate autologous reconstruction * Delayed-immediate implant reconstruction (2-stage) * Comparison of quality of life between the two groups. * Comparison of local and regional control rates between the two groups. III. Tertiary Objective: * Comparison of cosmetic evaluations between the two groups. * Dosimetry analysis for correlation between the occurrence of complications and the dose profile.