Generally, radiotherapy is required after breast-conserving surgery, but some patients with low-risk ductal carcinoma in situ, elderly patients without lymph node metastasis, and patients with low-risk invasive carcinoma may be considered to be exempted from radiotherapy under the advice of physicians. There is a risk of residual cancer cells in breast-conserving surgery, so breast-conserving surgery usually requires postoperative adjuvant radiotherapy, and the mode, dose and frequency of adjuvant radiotherapy are related to the size of the lesion and the metastatic status of lymph nodes. If patients with ductal carcinoma in situ meet the requirements of molybdenum target screening, lesion ≤2.5cm, low-intermediate grade, and margins ≥3mm, they are low-risk patients and are recommended to undergo whole-breast radiotherapy, or exempted from radiotherapy according to the patient’s wish and personal situation. Patients with invasive breast cancer can be exempted from radiotherapy if they are elderly and low-risk patients. “Elderly low-risk patients should meet the conditions of ≥70 years old, lesion ≤2cm, no lymph node metastasis, estrogen receptor positive, margin negative, and can receive standardized endocrine therapy. Patients are advised to communicate fully with their specialists and choose the appropriate treatment plan according to their condition.