Conventional radical breast cancer surgery is very traumatic and completely removes the breast, which will cause great harm to the patient both physically and psychologically. Some patients would rather pay the price of life than remove the breast, and as a doctor at that time, it was difficult to understand this patient’s thinking. In fact, as early as the 1980s, surgeons in Europe and the United States found that early stage breast cancer could be cured by preserving breast surgery with adjuvant radiation therapy, chemotherapy and endocrine therapy after a long period of time and a large number of patients’ treatment studies, which has now become the preferred procedure for early stage breast cancer in Europe and the United States. Breast-conserving surgery for early-stage breast cancer has been carried out in our hospital since 1999 and has been highly praised by patients. However, not every early-stage breast cancer can be treated with breast-conserving surgery. Strict selection of cases is necessary to ensure the quality of treatment and to reduce tumor recurrence as well as to achieve cosmetic purposes. What are the patients with breast cancer who can undergo breast-conserving surgery? 1. Early stage breast cancer (preferably with small lumps and no lymph node metastasis or distant metastasis). 2.Clinically, breast cancer ≤3 cm, the tumor is too large because of the large resection area, and it is easy to deform the breast after surgery, which cannot achieve the aesthetic effect. 3.Tumor located ≥3 cm from the areola, especially in the upper outer quadrant of the breast. 4.The patient has the requirement of breast preservation. 5.The patient has the condition of receiving the whole treatment and lifelong follow-up. However, patients with small breasts and large tumors are not suitable for breast-conserving surgery because of the difficulty in maintaining aesthetic appearance after surgery; patients who cannot adhere to adjuvant radiotherapy or have contraindications to radiotherapy after surgery, such as pregnant women and patients with collagen vascular diseases; patients with multifocal or multicenter origin breast cancer and those who cannot achieve negative tumor margins during surgery are also not eligible for breast-conserving surgery, but still choose modified radical surgery. In order to achieve the goal of breast preservation, early detection of breast cancer becomes the key. In recent years, the incidence of breast cancer in China has increased significantly, and the number of deaths has now become the first cancer death among women, while the treatment effect is worse than that in developed countries because the rate of early breast cancer in China is low, not more than 20%, while in the United States, it reaches 80%. In addition, the importance of breast cancer screening is generally not well understood, and most breast cancer patients go to hospital only after they have symptoms, which are often already in the middle and late stages.