This is a prospective, non-controlled, feasitility study. The tumor-bed boost part of the radiotherpay is put forward, 7-14 days before the definitive surgery. A single dose of 10Gy is prescribed to the tumor bed. In order to identify the tumor accurately, MRI guided radiotherapy is applied under the MR-linac. The breast surgery is planned after recovery from radiation induced acute toxicity, within 14 days. The surgeons would undertake lumpectomy only or an additional oncoplastic surgery, with axillary nodal evaluation with sentinal nodal biopsy or dissection. After wound healing, postoperative whole breast radiotherapy is administered, within 6 weeks following surgery. The dose is 26Gy/5.2Gy/5 fractions. Adjuvant systemic therapy is held until the end of the radiotherapy, no more than 12 weeks from surgery implementation.
