Over the past half century, the treatment of breast cancer has undergone epoch-making changes, and the era of mainly surgical treatment has transformed into a new era of comprehensive treatment, however, surgery-based local treatment is still the main treatment for breast cancer. The history of surgical treatment of breast cancer has gone through the process from simple tumor resection → standard radical surgery, expanded radical surgery → modified radical surgery with preservation of pectoral muscle → modified radical surgery with preservation of pectoral muscle and pectoral nerve → breast-conserving surgery and sentinel lymph node biopsy. The evolution of breast cancer surgery originates from the change and update of treatment concept and the in-depth research of basic theory. The early stage of simple tumor resection This primitive surgical approach is related to the lack of understanding of the biological behavior of malignant tumors at that time. This surgical procedure lasted from the 15th century to the middle of the 19th century, documented by Pare’s mass excision (1510-1590), Vesalius’ extensive local excision (1514-1564), Severinus’ “radical surgery” including pectoral muscle and axillary lymph node excision ( 1580-1645). 1580-1645) and Herster’s so-called “extended radical surgery” including removal of the ribs (1680-1768). At that time, the mortality and complications of the operation were high and the prognosis of patients was very poor. Halsted radical surgery At the end of the 19th century, Halsted believed that the development of breast cancer was based on local infiltration of tumor cells, followed by metastasis along the lymphatic tracts and finally hematogenous dissemination. The Halsted procedure involves the removal of the entire breast including the tumor, the skin and surrounding tissue, as well as the pectoralis major and minor muscles and axillary lymph nodes. This procedure is a new era in the history of breast cancer surgery and is known as the “classic” radical breast cancer surgery. It has increased the 5-year survival rate of breast cancer from 10%-20% to 40%-50%. However, Halsted radical surgery also has disadvantages that cannot be ignored, such as a high incidence of postoperative upper limb edema, chest deformity and flap necrosis. Radical surgery not only cruelly destroyed women’s perfect body shape, but also affected their family, career choice, life attitude, and heart health, etc. Despite this, Halsted’s surgical method has ruled for most of the century. 3.Extended radical surgery The distribution of internal breast lymph nodes was first described by Stibbe through autopsy in 1918. in the late 1940s, it was recognized that in addition to axillary lymph nodes, internal breast lymph nodes were also the first stop of breast cancer metastasis, and with the development of anesthesia and thoracic surgery techniques, Margottini (1949) and Urban (1951) proposed radical surgery combined with In addition to the development of anesthesia and thoracic surgery techniques, Margottini (1949) and Urban (1951) proposed an expanded radical surgery of the internal mammary lymph nodes by combining extrapleural and intrapleural clearance of the internal mammary lymph nodes. Since then, a large number of prospective clinical trials and multicenter studies have gradually shown that there is no statistical difference in the efficacy of expanded radical surgery and classical radical surgery or modified radical surgery for breast cancer, and the postoperative complications and sequelae are high, so it is gradually abandoned. The failure of treatment lies in distant metastasis, and blindly expanding the scope of local surgery cannot improve the prognosis of patients. This was soon confirmed by several international randomized multicenter clinical trials. In 1948, Patey reported the Patey procedure and its Scanlon modification, which preserves the pectoralis major muscle and removes its fascia, and in 1963, Auchincloss reported another modified radical procedure that preserves the pectoralis major and minor muscles without removing or cutting the pectoralis minor muscle. This modification limited the dissection of high lymph nodes, but he concluded that only 2% of patients might benefit from dissection of high lymph nodes. The Auchincloss procedure has probably been the most commonly performed procedure in the world for some time. A series of prospective randomized studies have shown that the difference in overall and disease-free survival between patients after modified radical surgery and Halsted radical surgery is not significant, but the superiority in terms of functional recovery and its morphology is significant. However, with the modernization of radiotherapy equipment and techniques, as well as the development of postoperative chemotherapy and endocrine therapy and targeted therapy, breast cancer “reduction” surgery did not stop at modified radical surgery, but various breast-preserving surgical approaches emerged. The Milan I trial of quadrant mastectomy plus whole breast radiation for early breast cancer was conducted by Veronesi in Italy in 1981, followed by the US Surgical Adjuvant Breast and Bowel Cancer Program (NSABP) B-06 trial conducted by Fisher et al. The former advocated a quadrant or 1/4 mastectomy with axillary lymph node dissection, while the latter advocated local excision of the tumor and 1 cm of surrounding normal tissue with axillary lymph node dissection, followed by routine postoperative radiation therapy to the residual breast. After years of prospective, multicenter randomized clinical trials, a number of internationally renowned breast cancer collaborative groups such as NSABP, NCI Milan, and Gustave-Poussy have confirmed that local excision of early breast cancer plus radiotherapy has the same results as radical surgery plus radiotherapy. The combination of breast conservation and postoperative radiotherapy plus chemotherapy is now the conventional treatment for early-stage breast cancer in Europe and the United States. Currently, breast-conserving surgery accounts for more than 50% of all breast cancer surgeries in the United States, 70% to 80% in Singapore, more than 40% in Japan, 30% in Hong Kong, and the number is increasing in mainland China. In the early stage of breast-conserving surgery, there are strict restrictions on tumor size, generally within 75px, mainly for early stage tumors (T1 to T2). Absolute contraindications: (1) more than 2 foci visible to the naked eye in different quadrants or diffuse microcalcifications on mammography; (2) adequate radiation treatment to the affected breast; (3) breast cancer in pregnancy; (4) persistent positive cut margins. Relative contraindications: (1) large tumor/breast ratio; (2) connective tissue disease; (3) tumor located under the nipple; (4) very large breast. With the continuous development and proficiency of this technique, as well as the maturation of neoadjuvant chemotherapy and the improvement of radiological techniques in radiation equipment, the indications for breast-conserving treatment are being explored and some patients previously considered contraindicated for breast-conserving surgery have been successfully treated with breast-conserving treatment, even for locally advanced breast cancer (LABC). According to Peoples et al, the indications for breast-conserving surgery after neoadjuvant chemotherapy for LABC are: no skin edema, residual tumor diameter less than 125 px, no evidence of multicentric tumor lesions, no tumor metastasis in the internal breast lymph nodes or no obvious diffuse calcified foci in the breast. There is no evidence of multicentric tumor lesions, no tumor metastasis in the internal breast lymph nodes or no obvious diffuse calcification foci in the breast. In 1997, Cobanas first discovered and named the sentinel lymph node, which is defined as the lymph node that receives the first lymphatic drainage and the earliest lymph node metastasis among the lymph nodes in the drainage area of the primary tumor. 1993, Alex first reported the animal experiment of using radioactive tracer to label the sentinel lymph node. In the same year, Krag reported a clinical study of intraoperative identification and biopsy of sentinel lymph nodes with a probe using 99m TC-labeled sulfur colloid in breast cancer patients. In the second year, Ciuliano reported the results of a study on the identification of sentinel lymph nodes using a blue dye (1% isothiolan) to label the lymphatic system. Sentinel lymph node biopsy in breast cancer has become a hot topic of research in oncology, and as Beechey-Xew-man described, sentinel lymph node biopsy (SLNB) is another major breakthrough in breast cancer surgery and has been considered the second revolution in breast surgery. Several clinical study interviews on SLNB as an alternative to axillary lymph node dissection have shown that if there are no metastases in the anterior lymph nodes, axillary lymph node dissection can be considered as an option. The accuracy of SLNB in predicting positive axillary lymph nodes can reach 90%-98%, while the false-negative rate can be controlled at 5%-10%, and the only lymph node with metastasis is the sentinel lymph node in about 38%-76% of patients. SLNB can not only clarify the presence or absence of metastasis in axillary lymph nodes, but also eliminate unnecessary axillary lymph node dissection in patients with negative sentinel lymph nodes, reduce the blindness of surgery, and improve the quality of life of patients. Successful sentinel lymph node biopsy is defined as biopsy of more than 1 sentinel lymph node, so how to accurately locate the sentinel lymph node is crucial. The main techniques currently available are enhanced CT, MR I, SPECT, and γ2 counter. Among them, γ2 counter can accurately scan hot spots quantitatively, so biopsy can be performed on very small lesions. 7.Breast reconstruction Breast reconstruction includes phase I reconstruction and phase II reconstruction, which can be performed with self-flap or breast prosthesis, or a combination of both. Studies have shown that breast reconstruction does not have a negative impact on local recurrence and overall survival, so every post-mastectomy patient is a potential candidate for reconstruction without interfering with disease diagnosis and follow-up. Overall, first-stage reconstruction is superior to second-stage reconstruction. First-stage reconstruction saves time, improves safety, reduces costs, and alleviates psychological barriers; skin-sparing mastectomy (SSM) improves the naturalness of the reconstructed breast, preserves skin nerve endings, and does not affect local recurrence rates. Autologous tissue is the tissue of choice for reconstruction. The transverse rectus abdominis muscle (TRAM) flap, free TRAM flap, inferior epigastric artery perforator (DIEP) flap, and latissimus dorsi muscle flap are the most common choices. Other reconstructive procedures such as super-charged TRAM flap, gluteus maximus flap, and superior gluteal artery perforator flap have also been performed.