The occurrence of 12 lymph node metastases in breast cancer patients suggests that the disease has progressed to middle-late stage and the condition is serious. Breast cancer is a malignant tumor that occurs in the epithelial tissue of the breast, and with the progression of the disease, lymph node metastasis manifestations such as axillary lymph nodes, subclavian lymph nodes, and internal breast lymph nodes can occur. According to the criteria of tumor TNM staging and clinical staging, when breast cancer patients show 12 lymph node metastases, their condition has progressed to stage pN3a, i.e., stage IIIC of clinical staging, and their condition is serious. For IIIC stage breast cancer patients, neoadjuvant chemotherapy is the first choice of treatment to reduce the inoperable stage to operable stage, and some patients can choose targeted or immune drug therapy to prolong the survival time and improve the quality of life. It is suggested that breast cancer patients should go to regular hospitals for regular follow-up and follow the advice of specialists to standardize the diagnosis and treatment, so as to avoid delaying the condition.