Hypofractionated breast cancer is a kind of differentiation level in breast cancer. The differentiation level of breast cancer is divided into undifferentiated, hypofractionated, moderately differentiated and highly differentiated, the lower the differentiation level, the more different the breast cancer cells are from normal breast cells, the higher the malignancy level, and the more likely to have distant metastasis. Therefore, if the postoperative pathology of breast cancer shows that the breast cancer is hypofractionated, it is often a factor of poor prognosis of breast cancer.