Super Hypofractionated Irradiation for Whole Breast Treatment

Eligible breast cancer patients will receive SHF-WBI of 5.2 Gy in 5 fractions to ipsilateral whole breast within one week and a sequential tumor bed boost of 5.2 Gy in 2 fractions at the discretion of the radiation oncologist. All patients are treated with intensity modulated radiation therapy (IMRT) technique. The primary endpoint is ≥2 grade any acute radiation induced toxicity event. Patients will be followed for at least 5 years to evaluate the acute and late radiation-induced toxicity, locoregional recurrence, distant metastasis, death and quality of life. Calculation of the required number of cases based on an alpha of 0.05 and a power of 80% with a maximal tolerable toxicity difference of 10% during and within 6 months after SHF-WBI comparing to hypofractionated whole breast irradiation(40-42.5Gy/15-16Fx) and lost rate of follow up of 10%. In total 217 patients are needed to be recruited.