Whether breast cancer has metastasized or not can be judged based on the relevant symptoms and relevant examinations. However, it mainly depends on relevant examinations. 1. Symptoms: When breast cancer metastasizes, patients may feel all kinds of discomforts, such as tiredness, poor mental state and so on. After metastasis through lymph nodes, it will cause enlarged lymph nodes and lymphatic pain. After metastasis through the lungs, patients may experience symptoms such as coughing, coughing up phlegm, difficulty in breathing, etc. After metastasis through the liver, there will be pain in the liver area, yellowish color, yellowish sclera, etc. However, it is not objective to rely solely on symptoms for judgment. 2. Examination: Breast cancer patients need to undergo regular review, including whole-body bone scan, chest CT, liver ultrasound, etc., which can analyze whether there is metastatic cancer in each part according to the relevant examination, and then judge the metastasis through the value of tumor markers. Breast cancer patients should be diagnosed and treated early to effectively prevent metastasis or proliferation, but the specific treatment should be carried out under the guidance of professional physicians, and should not use drugs without authorization. During the treatment, the mind should be calm and avoid excessive fear.