Breast cancer metastases mainly include direct spread metastasis, lymphatic metastasis, and hematogenous metastasis, etc. The lesions can be metastasized to nearby lymph nodes and various tissues and organs in the body. Breast cancer metastases and common metastatic sites are divided into the following: 1) direct metastasis: breast cancer cells can directly invade surrounding tissues, resulting in lesions in normal breast, skin, muscle and other tissues; 2) lymphatic metastasis: breast cancer cells can metastasize to ipsilateral axillary lymph nodes via lymphatic vessels, and then involve supraclavicular lymph nodes to develop lesions. Patients with lymph node metastasis often have enlarged lymph nodes with indistinct borders and hard texture; 3. Hematogenous metastasis: Patients with supraclavicular lymph node metastasis may have cancer cells enter the jugular vein through the thoracic duct or neck lymph nodes to induce hematogenous metastasis, which may involve the whole body tissues and organs. In addition, breast cancer cells may directly invade the veins and cause metastasis to the bone structures such as the spine, pelvis and femur, as well as the lungs and liver. Patients with lesions involving bone tissue often suffer from severe pain in the affected area, which may even affect walking function in severe cases. Patients with lung metastases usually present with symptoms such as coughing, coughing up sputum, and difficulty in breathing. Patients with liver metastases often present with symptoms such as liver enlargement and jaundice.