Breast cancer is one of the most common malignant tumors in women and poses a serious health risk to women. Surgical procedures are the main treatment for breast cancer. The history of breast cancer surgery is divided into five stages: primary local excision, radical mastectomy, extended radical mastectomy, modified radical mastectomy and breast-conserving surgery. Among them, modified radical surgery and breast-conserving surgery are commonly used in the treatment of breast cancer, especially breast-conserving surgery is the best surgical procedure for early-stage breast cancer (clinical stage I and II), considering both the therapeutic effect and aesthetics. Throughout the history of breast cancer surgery, there have been two major revolutionary changes. The first change was in the late 19th century (1894) when William Stewart Halsted, a great surgeon and pathologic anatomist, proposed a new theory on the pathway of breast cancer spread through extensive clinical observations and pathologic anatomical studies. local infiltration of tumor cells, followed by metastasis along lymphatic tracts, and finally hematogenous dissemination. In other words, within a certain time frame, breast cancer is only a localized lesion and can be cured if the tumor and regional lymph nodes are completely removed within this period. So in 1882, he created radical breast cancer surgery, which is the complete removal of the entire breast including the tumor, a considerable area of the breast skin and surrounding tissues, and the large and small pectoral muscles and axillary lymph nodes. In 1948, Patey reported that the pectoralis major muscle was preserved during Halsted radical surgery and the pectoralis minor muscle was removed to preserve the better shape and function of the chest wall for breast reconstruction. In 1951, Auchincloss proposed to preserve the pectoralis major and minor muscles, both of which are known as modified radical surgery. A large number of clinical studies have shown that there is no significant difference in survival and local recurrence rates between radical surgery and modified radical surgery for patients with clinical stage I and II breast cancer, and coupled with the obvious superiority of modified radical surgery in functional recovery and cosmetic surgery, modified radical surgery has become the standard of care for almost all patients with resectable breast cancer. The second change occurred in the last 30 or 40 years. In the 1970s, Fisher et al. proposed that breast cancer is a systemic disease from the beginning, and cancer cells can cause systemic disseminated metastasis through the tumor blood vessels themselves at an early stage, and lymph node metastasis is a factor affecting prognosis, but not a decisive factor. Blood metastasis is an important way of breast cancer dissemination, and there is no correlation with regional lymph node metastasis or not. Based on this theory, breast-conserving surgery was born. Breast-conserving surgery is a procedure that preserves the breast. It includes quadrant excision, segmental excision, local excision plus axillary lymph node dissection (axillary lymph node dissection may be excluded if the biopsy of the anterior lymph node is negative), followed by whole-breast radiotherapy and, depending on the pathology, chemotherapy, endocrine therapy or targeted drugs. A large number of clinical studies have proved that there is no significant difference in survival rate between breast-conserving surgery and modified radical surgery for stage I and II breast cancer patients. With the rapid development of medical technology, the concept and mode of modern breast cancer treatment has been changing, which has significantly improved the survival rate and quality of life of breast cancer patients. This change is reflected in: 1. the replacement of the anatomically oriented principle by the biologically oriented treatment concept, i.e., the change from local to systemic disease understanding. 2. The shift from anatomical concept-guided radical surgery to minimally invasive breast-conserving treatment. 3.Shift from single surgical treatment mode to multidisciplinary comprehensive treatment. 4.Shift from traditional non-specific and cytotoxic drugs to targeted drug therapy. Since breast-conserving surgery preserves relatively intact breast appearance and improves patients’ quality of life under the premise of ensuring treatment quality, breast-conserving surgery has become an ideal choice for early-stage breast cancer patients who have the desire to preserve breast. However, breast-conserving surgery has the following absolute contraindications: 1. Pathological persistent positive tumor margins 2. Those who are unwilling to receive breast radiotherapy after surgery. 3. Previous radiotherapy to the breast or chest wall. 4.Requiring radiotherapy during pregnancy. 5.Molybdenum target or MRI shows diffuse distribution of malignant or suspected malignant microcalcifications. 6.Multicentric lesions. Large tumors and small breasts that cannot achieve good breast appearance after surgery, multifocal lesions requiring at least 2 different incisions and active connective tissue diseases (scleroderma and systemic lupus erythematosus, etc.) are relative contraindications to breast-conserving surgery. Combined with the above condition of Ms. Wang in Inner Mongolia, she is considered a clinical stage I or II patient with a single tumor, a desire for breast conservation and acceptable for postoperative radiotherapy, and can choose breast conservation surgery without total breast excision.