Chemotherapy for breast cancer is currently considered to be a chemotherapy-sensitive tumor, and combination chemotherapy can significantly improve the outcome of breast cancer, especially premenopausal breast cancer. At present, preoperative chemotherapy is mostly administered for breast cancer, that is, chemotherapy is administered before surgery. Preoperative chemotherapy has two basic purposes: 1. It is to enhance the control effect of systemic micro-metastases of breast cancer while the patient is still in good health, so as to reduce the chance of systemic metastases and improve the survival rate. 2. It is to improve the local control effect, that is, it can shrink the tumor and increase the proportion of treatment that preserves the breast. Preoperative chemotherapy can also be regarded as a kind of drug sensitivity test, which is conducive to the development of individualized breast cancer chemotherapy regimen. Radiation therapy for breast cancer is a local treatment method, which is mostly used for local treatment before and after surgery, as well as for local control of recurrent breast cancer. It is mostly used for post-surgical treatment of axillary lymph node metastasis with more than 4, whole breast irradiation after breast-conserving surgery, and pre-operative tumor reduction to facilitate surgical treatment. Endocrine therapy for breast cancer is believed to be closely related to the stimulation of estrogen in the body, and endocrine therapy is a kind of treatment to counteract the effect of estrogen. Although endocrine therapy targets the “root” of breast cancer, it has limited effect on breast tumors that have already appeared. At the time of the patient’s visit, there are a significant number of cancer cells that can survive without estrogen, so endocrine therapy will not be effective at this time. Surgical treatment of breast cancer Surgical treatment is still the main treatment for breast cancer. Its aim is to remove the early local lesions and to bring the tumor under local control. Surgical treatment does not necessarily involve complete removal of the breast. The results of numerous studies have shown that it is feasible to preserve the breast for patients with early stage breast cancer without sacrificing safety. This will have much less psychological impact on the patient after surgery.