During the period of radiotherapy and chemotherapy after surgery, breast cancer patients should firstly have their blood and liver functions checked regularly. Because radiotherapy and chemotherapy are cytotoxic, not only to tumor cells but also to normal cells, which may cause severe decrease in white blood cells due to bone marrow suppression and damage to liver cells, it is important to closely monitor and regularly check blood and liver function during treatment. If there is a serious drop in white blood cells and significant damage to liver function, you should seek medical treatment promptly. Breast cancer patients should also have regular chest X-ray to monitor whether there are metastases in the lungs; regular abdominal ultrasound to observe the liver, because breast cancer patients may have metastases in the liver; if there is back pain or limb pain, then an isotope bone scan should be done to observe whether there are bone metastases; if there is headache with severe pain and progressive aggravation, then an electroencephalogram or brain CT examination should be done to clarify whether brain metastasis has occurred. In patients with mastectomy, the contralateral mammary gland should be examined by X-ray once a year. Radiographs should be taken 6 months after breast-conserving surgery on the affected side, and then once a year for both breasts. Patients taking tamoxifen have annual pelvic examinations. The regular follow-up after breast cancer surgery is usually: the month of surgery as the starting time, every three months for two years after surgery, every six months for 3-5 years after surgery, and then once a year for the rest of life. The follow-up program includes medical history and physical examination. In addition, it is important to emphasize that patients with breast cancer on one side have a much higher risk of breast cancer on the opposite breast.