The earliest metastatic site of breast cancer is usually located in the axillary lymph nodes. As the most common malignant tumor of breast, the cause of breast cancer is not clear, although it is a malignant tumor, the metastatic route usually includes lymphatic metastasis and hematologic metastasis, especially in breast cancer, lymphatic metastasis is the main route of its metastasis, and the metastasis usually includes axillary lymph nodes and contralateral lymph nodes, so the earliest metastatic site of breast cancer is usually in Therefore, the earliest site of breast cancer metastasis is usually in the axillary lymph nodes on the same side. For breast cancer, early detection, early diagnosis and early surgical treatment are required. Surgical treatment is mainly radical or modified radical treatment of breast cancer, that is, complete removal of the local breast and removal of the ipsilateral axillary lymph nodes.