For stage I and some stage II breast cancer patients, breast preservation surgery is used, followed by radiotherapy and chemotherapy; for stage III breast cancer patients, neoadjuvant chemotherapy is given first, followed by surgery for better results. Breast cancer is the most common malignant tumor among women, and the incidence of breast cancer is increasing year by year all over the world. However, epidemiological data in the United States show that the mortality rate of breast cancer is decreasing year by year, which is related to the enhanced screening, significantly improved detection of early breast cancer and systematic adjuvant treatment. The study showed that about 1%-5% of breast cancer cases are related to the disease. The study showed that about 1% to 5% of breast cancer patients were found to have metastatic lesions at the time of consultation. The vast majority of patients require systemic medical treatment because of the possibility of systemic metastases in the early stages of breast cancer. This treatment model has been widely accepted, and breast-conserving surgery with adjuvant systemic therapy has been widely adopted for early-stage breast cancer. The development of clinical chemotherapy regimens for breast cancer has gone through the course of single-agent chemotherapy and combination chemotherapy. The first line of treatment has evolved from cyclophosphamide (CTX), 5-fluorouracil (5-FU), methotrexate, etc. to the use of anthracyclines (Adriamycin, ADM and Epi-Aminomycin, EPI) in the 1980s. The use of paclitaxel-based drugs (Tyso, Tysodi) in the nineties has led to a significant improvement in the prognosis of breast cancer. Some newly developed antitumor drugs including gemcitabine (GEM) and capecitabine (Xeloda, Xeloda) have made effective remedial treatment available for patients with advanced breast cancer. Commonly used chemotherapy drugs include CTX, ADM, Epi-ADM, MTX, 5-FU, Xeloda, Paclitaxel, Docetaxel, Gemcitabine, etc. I. Adjuvant chemotherapy Systemic adjuvant therapy has been widely accepted because most people believe that reducing tumor load is helpful to improve the efficacy of antitumor therapy. Most studies have proven this view. Adjuvant chemotherapy can effectively reduce the recurrence rate and mortality in early stage patients, therefore, adjuvant chemotherapy has become an important part of the comprehensive treatment of breast cancer. Postoperative adjuvant chemotherapy can reduce the recurrence rate and mortality of breast cancer patients, and adjuvant chemotherapy should be given to all patients with stage II or above. It was once thought that patients with negative axillary lymph nodes and primary foci less than 1 cm did not need adjuvant chemotherapy, however, about 25% of patients with negative axillary lymph nodes will have recurrence or metastasis later, therefore, it is now thought that adjuvant chemotherapy can be given to even early stage patients.