Whole-breast radiotherapy is a common clinical treatment for breast cancer, in which all breasts are irradiated with penetrating radiation to control the growth of tumors in the breasts. Whether it is after breast-conserving surgery or mastectomy, patients with lymph node metastasis or distal organ metastasis usually need to receive postoperative whole-breast radiotherapy, which is usually divided into 3~4 weeks or 5~7 weeks according to the patient’s specific conditions, and generally do not need to interrupt the targeted therapy during the radiotherapy period. Radiotherapy may cause damage to normal tissues of the body, which is generally unavoidable. For example, radiation pneumonitis, radiation skin damage. It is recommended that your doctor discuss with your family before you undergo whole breast radiotherapy, and that you are able to accept the damage caused by radiotherapy before you undergo whole breast radiotherapy.