Radiation therapy The need for radiation therapy after radical mastectomy is a controversial issue in the treatment of breast cancer. Currently, there is a convergence of opinion on postoperative radiotherapy, that is, postoperative radiotherapy for clinical stage I and lymph node metastasis-free cases does not improve the efficacy but may affect the immune system of the body; for stage II and patients with more than four lymph node metastases, postoperative radiotherapy can reduce the recurrence rate of local and regional lymph nodes, but does not significantly improve the survival rate. Therefore, postoperative radiotherapy is no longer used as a routine treatment after radical surgery. However, for cases with the possibility of recurrence, radiotherapy still has some value in reducing local recurrence and improving the survival rate. The indications of postoperative radiotherapy: 1.The whole chest wall and lymphatic drainage area should be irradiated after simple mastectomy. 2.After radical surgery, pathological examination of axillary lymph node metastasis, larger mass diameter than 5Cm, or metastasis in the middle and upper axillary lymph nodes is recommended for irradiation of supraclavicular region and internal breast area. 3.Irradiation of supraclavicular lymph nodes and/or internal mammary lymph nodes should be performed if pathology confirms metastasis in internal mammary lymph nodes after extended radical surgery or internal mammary lymph node exploration. After radical surgery for preoperative lesions located centrally or medially, additional irradiation of supraclavicular lymph nodes and internal mammary lymph nodes may be considered, especially in cases with metastases in axillary lymph nodes.