How to treat after surgery? 1.No chemotherapy and no radiotherapy are needed. 2.Is endocrine therapy necessary? A: Most doctors believe that endocrine therapy is necessary, but this is a controversial issue. The current evidence of endocrine therapy for DCIS is mainly focused on patients with breast-conserving surgery, and its main purpose is to prevent ipsilateral breast recurrence after breast-conserving surgery. However, for mastectomy patients like you, the probability of ipsilateral local recurrence after surgery is less than 1% (a near cure, if you will! Many studies have confirmed this conclusion), so there is no need for endocrine therapy to prevent ipsilateral recurrence in a patient like you. However, most doctors in China do not hesitate to give endocrine therapy for the main reason of preventing breast cancer in the contralateral breast, but only the risk of breast cancer in the next 5 years is more than 1.67%, and the data in Europe and the United States is about 3%, while there is a lack of similar data in China, and indirect evidence shows that the data in China is much lower than 1.67%. So out of prevention of contralateral breast cancer occurrence for Chinese patients is also an immature view. 3. Is ki67(+) 45% too high and what are the implications for the future? A: It has almost no effect on you. The reasons are: (1) Ki67 expression is very controversial in invasive carcinoma, let alone DCIS; (2) although some studies have shown that high KIi67 expression has a negative impact on ipsilateral breast recurrence, you have already had a mastectomy and there is no concern.