Breast cancer chemotherapy during the aggravation of the disease need to change the chemotherapy regimen or combined with radiation therapy, endocrine therapy, targeted drug therapy and so on. 1. Replacement of chemotherapy regimen: if the disease progresses during chemotherapy, it is necessary to replace the second-line regimen of chemotherapy. 2. Radiation therapy: breast cancer patients with aggravated condition during chemotherapy need to be treated with radiation to control local lesions, which can improve clinical symptoms and improve patients’ quality of life. 3. Endocrine therapy: For ER or PR positive patients, they can consider stopping chemotherapy and change to endocrine therapy, commonly used drugs such as letrozole, anastrozole and other aromatase inhibitors, as well as anti-estrogen drugs such as toremifene and tamoxifen, etc. In addition, patients can also follow the doctor’s instructions to control the local foci. In addition, patients can also use leuprolide, goserelin and other luteinizing hormone-releasing hormone analogs as prescribed by the doctor. 4. Targeted drug therapy: Breast cancer patients’ condition worsens during chemotherapy, for HER-2 positive patients, they can combine with Pertuzumab, Trastuzumab, etc. It is recommended that breast cancer patients who have symptoms during chemotherapy should take Pertuzumab, Trastuzumab, etc. for treatment. It is suggested that breast cancer patients need to consult doctor in time when their condition worsens during chemotherapy, and the doctor will choose appropriate measures according to the patient’s condition.