During the study, the patients would undergo radiation of 5.2Gy for 5 fractions to the prophylactic radiation volumes and and a 6Gy per-fraction simultaneous boost to the tumor bed or other high-risk volumes. Acute toxicity of grade 2 or higher in the following 12 weeks after radiotherapy is the primary end point.
This is a phase II study to investigate the feasibility of Ultra-hypofractionated radiotherapy with or without simultaneous integrated boost for low risk breast cancer patients who have received breast conservative surgery of mastectomy.