Currently, breast cancer surgery is becoming smaller and smaller than before, and the previous extended radical and radical surgery has basically been abandoned and replaced by modified radical and breast-conserving surgery, especially breast-conserving surgery, which shows a windy progress, but everything needs to be treated rationally. The following is a description of the indications and contraindications for breast-conserving surgery. The indications for breast-conserving surgery for breast cancer patients are: 1. If the tumor is less than 3 cm, if the ratio of tumor to breast size is small, breast-conserving surgery is still feasible even though the tumor is larger than 3 cm. 2. 2. Breast-conserving surgery can be chosen for those whose tumor edge is greater than 2cm from the edge of areola and can maintain a good shape of the breast after surgery; breast-conserving surgery can also be considered for those whose preoperative examination reveals that the lesion is of multicentric type or mammogram shows multiple tiny calcifications. Breast-conserving surgery has no special requirements on pathological types. Invasive lobular carcinoma, invasive ductal carcinoma and intraductal carcinoma in situ can all be selected for breast-conserving surgery. 4. It should be noted that if axillary lymph node metastasis is found, breast-conserving surgery cannot be actively performed even if other conditions are available. Contraindications to breast-conserving surgery There are 8 main contraindications to breast-conserving surgery: 1) lesions larger than 4 cm with unclear borders; 2) lymph nodes in the axilla are obviously enlarged or clinically considered to have lymph node metastasis; 3) multiple lesions; 4) those who cannot guarantee effective and adequate radiotherapy, those with previous history of radiotherapy in the breast area, those with collagen vascular disease; 5) small breasts but large tumors Those who are unwilling to receive breast-conserving surgery; 7.Breast-conserving surgery is not suitable for early and middle pregnancy because it is an absolute contraindication to radiotherapy, but breast-conserving surgery can be performed for late pregnancy and radiotherapy can be performed after delivery; 8.Cancerous tumor located in nipple and areola.