Modern medicine has more knowledge about the mechanism of breast cancer and large-scale clinical studies have made the treatment more standardized, which is fully possible as long as the treatment guidelines are strictly followed. First of all, digital mammography, ultrasound and MRI (magnetic resonance imaging) can help doctors understand the extent of the tumor, whether there is intraductal cancer, whether it is a single lesion or multiple lesions, and other information to assess whether there is a possibility of breast conservation. Ultrasound can also guide the surgeon to correctly grasp the scope of resection during surgery. In addition, the surgeon has to perform the necessary pre-surgical puncture biopsy according to different cases to clarify the diagnosis and the possible extent of tumor infiltration to reduce missed or incomplete resection. In addition, the surgeon must work closely with the pathologist during the surgery to ensure that there is no cancerous tissue infiltration at the edge of the tumor resection. Breast-conserving surgery is a form of surgical treatment for breast cancer, and it has a lot to do with the patient’s wishes, not breast-conserving for the sake of breast-conserving, after all, the treatment effect is still the first consideration. Some patients can achieve breast-conserving wishes after a pre-surgical radiotherapy step-down.