If 1~2 lymph node metastasis of breast cancer is performed with total mastectomy + axillary lymph node dissection, low-risk patients with cancer foci ≤5cm can be treated without radiotherapy, and the rest should be treated with radiotherapy. Radical surgery for breast cancer includes breast-conserving surgery, total mastectomy, and selective sentinel lymph node biopsy and axillary lymph node dissection. If breast cancer patients undergo breast-conserving surgery and have 1~2 lymph node metastases, radiotherapy should be given regardless of the size of the lesion, which serves to eliminate possible residual tumor cells. If the patient undergoes total breast excision + sentinel lymph node biopsy surgery and has 1~2 lymph node metastasis, axillary radiotherapy should be performed, and chest wall radiotherapy should be selectively performed according to the size of the mass and margins of incision. If patients underwent total mastectomy + axillary lymph node dissection surgery, low-risk patients with lesions ≤5cm (i.e., staging T1~2), age >40 years, histologic grading 1~2, strong positive estrogen and progesterone receptors, negative margins, and no lymphovascular invasion were exempted from radiotherapy. However, if the lesion is >5cm, suspected lymph node metastasis in the internal breast or clavicular region, unsatisfactory margins, and high-risk patients still need to consider radiotherapy. It is recommended that patients should consult with their specialists in time to choose the appropriate treatment plan and receive treatment according to the doctor’s instructions.