Radiation therapy after breast-conserving surgery for early breast cancer: 1. Indications: Radiation therapy is required after breast-conserving surgery for early breast cancer. The first radiotherapy after breast-conserving surgery should be started within 4-6 weeks after the incision is healed. 3.Radiotherapy technique and dose can be applied by 3D conformal or intensity modulation technique. The whole breast irradiation dose is 45~50Gy, 1.8~2Gy/time, 5 times/week. The dose can be added simultaneously to the tumor bed, or after the whole breast irradiation, the tumor bed area is usually required to make up the dose of 10~16Gy/5~8 times. Radiotherapy after radical surgery or modified radical surgery for breast cancer: 1. Indications: One of the following high-risk factors requires postoperative radiotherapy 1) T3 or above: the maximum diameter of the primary tumor is ≥5cm, or the tumor invades the breast skin and chest wall; 2) PN2: axillary lymph node metastasis ≥4. (3) T1/T2 patients with one to three axillary lymph node metastases, with the following high-risk recurrence risks: age ≤ 40 years, number of axillary lymph node clearances < 10, proportion of axillary lymph node metastases > 20%, hormone receptor negative, and Her-2/neu overexpression, radiotherapy can also be considered. (4) Positive surgical margins, intravascular tumor embolus 2, postoperative radiotherapy site and dose: chest wall and supraclavicular are the conventional target areas for postoperative adjuvant radiotherapy. The conventional dose of postoperative adjuvant radiotherapy is 50Gy/5 weeks/25 times, and the dose can be locally increased to 60Gy or more for the area with high suspicion of residual. General radiotherapy: electron beam radiotherapy, or 6MV-X-ray conformal or intensity-modulated radiotherapy can be used. After radical surgery for primary foci located in the central or medial breast, the inner breast area of the package is considered. Axillary radiotherapy is generally not done to avoid serious complications, but for those with residual lesions in the axilla, which are difficult to be removed by surgery more than 2 cm, or those with cancer thrombus formation in the axillary vessels, axillary irradiation can be added.