For breast cancer patients with small lumps and no metastasis in the axillary lymph nodes, radiotherapy is often not needed. If the breast cancer lump is large or the lymph nodes in the axilla have metastasis, radiotherapy to the chest wall and upper and lower clavicle area should be considered to reduce the chance of chest wall recurrence. If the patient has not undergone radical mastectomy but breast-conserving surgery, local radiotherapy is also needed after surgery to reduce the chance of local recurrence of breast cancer and thus improve the cure rate.