Since the 1990s, the incidence of breast cancer has been on the rise, but the mortality rate has declined. It is now believed that the reason for the decline in breast cancer mortality is related to the early diagnosis of breast cancer and advances in comprehensive treatment, especially in postoperative adjuvant therapy. I. General strategy of breast cancer treatment According to the NCCN guidelines, the treatment principles for all stages of breast cancer are: Stage I, with surgery as the main treatment, currently tends to be breast-conserving surgery plus radiotherapy. For patients with high risk of recurrence, postoperative adjuvant chemotherapy can be considered. stage II, surgical treatment first, followed by postoperative adjuvant chemotherapy according to pathology and clinical conditions. Neoadjuvant chemotherapy may be considered for patients with large masses and a propensity for breast conservation. For some cases with large masses and a large number of lymph node metastases, selective radiotherapy can be given. stage III, neoadjuvant chemotherapy followed by surgery, followed by radiotherapy and chemotherapy according to clinical and pathological conditions. stage IV, comprehensive treatment based on internal medicine. Among them, stage I~III patients who are hormone receptor positive should be given endocrine therapy after the end of chemoradiotherapy. II. Indications of chemotherapy and endocrine therapy in postoperative adjuvant treatment of early breast cancer 1. Lymph node status and adjuvant chemotherapy (1) Early breast cancer, LN(-), with the following high risk factors for recurrence: age 2cm, histological grade 3, choroidal aneurysm embolus, ER(-), high expression of Her-2, etc., should be treated with postoperative adjuvant chemotherapy. (2) Early breast cancer, LN(+), should all be treated with adjuvant chemotherapy. Chemotherapy can reduce the recurrence rate and mortality, especially premenopausal patients benefit more obviously. 2. Choice of chemotherapeutic drugs and protocols At present, the commonly used protocols are AC or CAF protocols containing anthracyclines, in addition to paclitaxel-containing protocols such as AT, AC→T protocols, etc. TAM is the most widely used endocrine drug for adjuvant treatment. Oral TAM for 5 years can significantly improve the 10-year DFS and OS of patients, and postmenopausal patients can be treated with AI agents such as Letrozole, Anastrozole and exemestane. Adjuvant endocrine therapy should generally be administered after chemotherapy. The indications of chemotherapy and endocrine therapy in the treatment of metastatic breast cancer The aim of treatment for advanced metastatic breast cancer (MBC) is to relieve symptoms, improve QOL and prolong survival. The median survival time after treatment is 2-3 years. Some patients with ER(+) and no visceral metastasis can survive for a long time and maintain a good QOL after reasonable treatment. 1. Endocrine therapy in MBC Endocrine therapy is generally preferred for MBC patients because of its lower toxicity and better efficacy than chemotherapy. The indications are: age >35 years, DFS >2 years after adjuvant therapy, bone and soft tissue metastases, asymptomatic visceral metastases, ER and/or PR positive, endocrine therapy is preferred. Premenopausal patients can be treated with surgical debulking or pharmacological debulking; TAM is effective for premenopausal patients; AI therapy is often chosen for postmenopausal patients. 2. chemotherapy in MBC Indications: For rapidly developing lesions, symptomatic visceral metastases, DFS.