Radiation therapy is a major component of the treatment of breast cancer and is one of the local treatments. Radiation therapy is mostly used for comprehensive treatment, including adjuvant treatment before or after radical surgery, and palliative treatment for advanced breast cancer. The following are the indications, contraindications and precautions of various radiotherapy modalities for breast cancer treatment. Indications, contraindications and precautions of radiotherapy for breast cancer I. Preoperative radiotherapy 1. (2) Rapid growth of tumor and significant growth within a short period of time. (3) The primary foci have obvious skin edema or pectoral muscle adhesions. (4) Those with large axillary lymph nodes or obvious adhesions with skin and surrounding tissues. (5) Cases with unsatisfactory tumor regression by preoperative chemotherapy. (6) Patients with inflammatory breast cancer who are striving for surgical resection. (1) It can increase the rate of surgical resection and give some inoperable patients another chance to have surgery. (2) Because radiation inhibits the vitality of tumor cells, it can reduce the recurrence rate and metastasis rate after surgery, thus improving the survival rate. (3) Because of radiation, the preoperative observation time is prolonged, and some cases with subclinical distant metastases can avoid an unnecessary surgery. 3.Disadvantages of preoperative radiotherapy Increase the complications of surgery and affect the correct postoperative staging and hormone receptor determination. 4.Application methods of preoperative radiotherapy Preoperative radiation should be used as much as possible with high-energy radiation, which can better protect normal tissues and reduce complications. In terms of radiation technology, most of them adopt conventional segmentation and medium dose at present. Rapid radiation or hyper-segmentation radiation is generally not used. It is ideal to perform surgery 4-6 weeks after the end of radiation. Whether radiation is needed after radical surgery was once the most debated issue in breast cancer treatment. In recent years, more authors have acknowledged that postoperative radiotherapy can reduce the local and regional recurrence rate. Since Fishor’s new view on breast cancer, the treatment of breast cancer has gradually shifted from local treatment to comprehensive treatment. Postoperative adjuvant chemotherapy is widely used, and postoperative radiation is no longer used as a routine treatment after radical surgery, but is selectively applied. 1. Indications (1) After simple mastectomy. (2) Pathological report of lymph node metastasis in the middle or upper axillary group after radical surgery. (3) Pathologically confirmed metastatic lymph nodes accounting for more than half of the total number of lymph nodes examined or more than four lymph nodes metastasized after radical surgery. (4) Cases with pathologically confirmed metastasis of intramammary lymph nodes (irradiation of supraclavicular region). (5) The primary focus is located in the center or inside of the breast after radical surgery, especially those with axillary lymph node metastasis. (1) After radical surgery or mock radical surgery for stage I or II breast cancer, if the primary lesion is in the outer quadrant of the breast and the pathological examination of axillary lymph nodes is negative, no radiotherapy will be given after surgery; if the axillary lymph nodes are positive, the inner breast area and the upper and lower clavicle area will be irradiated after surgery; if the primary lesion is in the central or inner quadrant of the breast and the pathological examination of axillary lymph nodes is negative, only the inner breast area will be irradiated after surgery; if the axillary lymph nodes are positive, the upper and lower clavicle area will be added. (2) After radical surgery for stage III breast cancer, irradiate the inner breast area and the upper and lower clavicle area regardless of positive or negative axillary lymph nodes. Depending on the number of positive axillary lymph nodes and the involvement of the chest wall, additional chest wall irradiation may or may not be considered. (3) After radical breast cancer surgery, the axillary lymph nodes have been cleared, so generally the axillary area will not be irradiated anymore, unless the surgical clearance is not complete or there are residual lesions, then additional axillary irradiation will be considered. (4) Radiotherapy should be started within 4-6 weeks after surgery, and can be extended to 8 weeks for those with implants. In the past, radiation therapy for locally advanced tumors and those without surgical indications was often palliative. In recent years, with the improvement and enhancement of radiation equipment and technology, as well as the progress of radiobiological research, radiation can make local tumor get higher dose with less damage to surrounding normal tissues, so the treatment effect is obviously improved. At present, research on minor surgery plus radiation for early breast cancer has begun, which has shifted radiation therapy from palliative to radical in the treatment of breast cancer. Most authors believe that minor surgery plus radiotherapy can be considered for patients with primary foci less than 3 cm, N0 or N1. For locally advanced breast cancer, radiation therapy is still an effective local treatment. Removal of the entire tumor or simple mastectomy before radiation can improve the curative effect. Radiation therapy for recurrence and metastasis Recurrence of breast cancer after surgery is a bad sign, but not hopeless. Appropriate local treatment can improve the quality of survival and prolong the survival period. For irradiation, large field irradiation is more effective than small field irradiation, so large field irradiation should be used as much as possible. For recurrent cases, combined treatment of radiation and chemotherapy should be used, especially for recurrent cases with rapid development. When distant metastasis of breast cancer occurs, chemotherapy should be considered first, and appropriate combination with radiation can relieve the symptoms and pain of patients. For example, pain can be reduced or disappeared after radiotherapy for bone metastases. For patients with thoracic and lumbar metastases, radiation can prevent or delay the occurrence of paraplegia. Therefore, in daily life, breast cancer patients should have a balanced diet, eat more beans, vegetables and fruits, eat less fatty foods, especially animal fatty foods should be eaten as little as possible, avoid unnecessary exposure to radiation, such as those who are engaged in radiation work, mining, to do their own protection work, there is no need not to do too many x-ray photos, fluoroscopy. Regularly participate in the unit organization of the census, early detection of disease.