The Postoperative Radiotherapy in N1 Breast Cancer Patients

1:1 randomization to the control group and experimental group, stratified by the type of surgery (breast-conserving surgery (BCS) versus mastectomy) and the type of histologic type (triple negative breast cancer (TNBC) versus non-TNBC) The control group: * If patients received BCS, WBI+Regional RT * If patients received mastectomy, PMRT The experimental group: * If patients received breast conserving surgery, WBI alone * If patients received mastectomy, No PMRT