Type A breast cancer is an estrogen receptor-positive breast cancer and is usually inert. Inert cancer refers to low-grade cancer where the tumor grows slower and is less likely to metastasize or spread. Type A breast cancer can be classified as PR positive and ER positive through immunohistochemistry results. This type of breast cancer is more suitable for endocrine therapy and is more sensitive to this therapy, and the prognosis is relatively high after regular treatment. Most of the patients can be diagnosed, detected, and treated early, and they can achieve clinical cure, and the survival rate will be improved, so type A breast cancer is inert cancer. In addition to endocrine therapy, type A breast cancer can also use cyclophosphamide and doxorubicin for chemotherapy; or utilize trastuzumab, lapatinib and other drugs for targeted therapy, and in the early stage, direct surgery can be performed to remove the mass, and after regular treatment, the survival rate of 5 years can reach 60%~80%. After the detection of type A breast cancer, patients should use medication reasonably under the guidance of doctors, but the specific medication plan as well as the treatment plan need to be selected according to the progress of the disease as well as the results of tumor marker screening.