Lymphatic metastasis: Lymphatic metastasis of breast cancer is the most common in clinical practice, and there are two main metastatic pathways: 1. The rate of axillary lymph node metastasis is very high in breast cancer patients, and it is the most common and early metastatic site, accounting for about 60% of patients. Axillary lymph node metastasis is related to the size of the primary tumor. The larger the size of the tumor and the more advanced the disease, the higher the number of axillary lymph node metastasis and the more metastases. Clinically, even if the enlarged axillary lymph nodes are not found, lymph node metastasis is often found after surgery. The metastasis rate of parasternal lymph nodes accounts for about 30%-50%. Cancer cells infiltrate into parasternal lymph nodes medially and then reach supraclavicular lymph nodes. Hematogenous metastasis: Breast cancer cells can directly invade blood vessels and cause distant metastasis. The veins of deep breast tissue, pectoral muscle and chest wall converge into axillary vein and enter the subclavian vein and the saphenous vein, which is an important way of pulmonary metastasis. The incidence of distant metastases from breast cancer is related to the size of the primary tumor, the number of lymph node metastases and pathological grading. The most common distant metastasis of breast cancer is lung, followed by bone, liver, soft tissue, brain and adrenal gland. Most of the lung metastases are nodules of different sizes in the lungs, and occasionally they are single nodules. In a few cases, they are manifested as cancerous lymphangitis with obvious clinical cough and shortness of breath and cyanosis. Bone metastases are most frequent in thoracic and lumbar vertebrae and pelvis, followed by ribs and femur; most of them are osteolytic changes, and a few are osteogenic; pathological fractures may occur in long bone metastases, and spinal metastases may cause paraplegia due to spinal cord compression, and clinically there is progressively increasing pain. 3. Early symptoms of liver metastasis are not obvious, and ultrasound imaging and CT examination can help early detection. Pleural metastasis is often secondary to pulmonary metastasis, but occasionally it can also be seen as simple pleural metastasis, mainly manifested as pleural effusion, which can be bloody, and sometimes cancer cells can be found in the pleural fluid. 5.Brain metastasis is a common primary focus in female patients and can be diagnosed with the help of CT examination. The above mentioned symptoms of breast cancer metastasis and spread are two major aspects and seven minor points, I hope every breast cancer patient will be careful to prevent the spread of breast cancer.