(1) Indications Radiotherapy is required for early breast cancer after breast-conserving surgery. The first radiotherapy treatment after breast-conserving surgery should be started within 4-6 weeks after the incision is healed. 3) Radiotherapy technique and dose 3D conformal or intensity modulation technique can be used. The whole breast irradiation dose is 45-50Gy, 1.8-2Gy/time, 5 times/week. After whole-breast irradiation, a supplementary dose of 10～16Gy/5～8 times is usually needed in the tumor bed area. 2.Radiotherapy after radical surgery or modified radical surgery for breast cancer (1) Indications Post-operative radiotherapy is required for one of the following high-risk factors: a. The maximum diameter of the primary tumor is ≥5 cm, or the tumor invades the breast skin or chest wall; b. Axillary lymph node metastasis is ≥4. c. T1/T2 patients with one to three axillary lymph node metastases, especially with the following high risk of recurrence: age ≤ 40 years, number of axillary lymph node dissection < 10, proportion of axillary lymph node metastases > 20%, hormone receptor negative, and Her-2/neu overexpression, radiotherapy can also be considered. (2) Postoperative radiotherapy site and dose The chest wall and supraclavicular are the conventional target areas for postoperative adjuvant radiotherapy. The conventional dose of postoperative adjuvant radiotherapy is 50 Gy/5 weeks/25 times, and the dose can be locally increased to 60 Gy or more for areas with high suspicion of residual.