Breast cancer is malignant in itself, so it is generally not called malignant breast cancer. Breast cancer generally refers to a lump in the breast with a hard texture and unclear border, which may have lymph node metastasis, and is a kind of malignant tumor. Most of them can be determined as breast cancer by ultrasound or mammography before surgery, or if necessary, by puncture for pathological examination, or by direct removal of the lump for pathological examination. Breast cancer is more likely to have lymph node metastasis or bloodstream metastasis, such as axillary lymph node metastasis, or subclavian or supraclavicular lymph node metastasis, or lung metastasis or bone metastasis. Most breast cancer patients are treated with good results, mainly including modified radical breast cancer surgery, which means removing the breast and then clearing the axillary lymph nodes, and deciding the next treatment plan based on the pathological results and immunohistochemistry results after the surgery.