Primary breast cancer refers to secondary breast cancer that originates from the breast and not metastasized from other parts. When primary breast cancer occurs, it is necessary to improve relevant examinations, such as chest CT, MRI, etc., to exclude whether there are metastases from other parts and secondary malignant tumors caused by other parts of the body. Carcinoma in situ is a kind of pathological staging of breast cancer, and the pathological staging of breast cancer is mainly based on TNM staging. Carcinoma in situ refers to the malignant lesions occurring in the epithelial layer of mucous membrane, but it has not broken through the submucosal basement membrane and invaded into the surrounding tissues, so at this time, its condition is light and the prognosis is relatively good, and it can be cured by surgical excision.