After looking at the treatment of stage 1 and stage 2 breast cancer, let’s learn more about what stage 3 breast cancer is. Stage 3 breast cancer is “extensive localized breast cancer”, where the breast tumor itself is large and there is metastasis of lymph node cancer in the axilla. In addition, invasive breast cancer that invades the skin or chest wall is also considered stage III. Inflammatory breast cancer, which has characteristics similar to inflammation of the breast, is stage III breast cancer. In some cases, the tumor in the breast is not large, but there are more than four lymph nodes in the armpit, or the lymph nodes have metastasized to the inner breast or the ipsilateral clavicle area. Since the characteristics of stage III breast cancer are widespread, the tumor may be larger and have more lymph node metastases, “preoperative adjuvant therapy” can be considered before surgical treatment. The advantage of preoperative adjuvant therapy is that it can shrink the tumor, which cannot be operated, to a size that can be treated surgically. At the same time, the response of cancer cells to these drugs can be understood, so that if preoperative adjuvant therapy is not effective, the drug or treatment can be changed quickly and the right medicine can be prescribed. Due to the widespread nature of stage III breast cancer, most patients undergo total mastectomy with lymph node dissection. Some may also consider breast conservation with lymph node dissection if they have received preoperative adjuvant therapy and the tumor is substantially smaller. Then, the patient may need additional radiation therapy to the chest and lymph nodes. Chemotherapy is also used to kill the cancer cells with a combination of different drugs. Then, depending on the tumor characteristics, whether the cancer cells are HER2-positive or ER- or PR-positive, additional targeted therapy and hormonal therapy may be indicated. In general, for the treatment of locally extensive stage III breast cancer, physicians usually recommend the following sequence: “preoperative adjuvant therapy” → “total mastectomy + lymph node dissection” → “radiation therapy” → “chemotherapy” → “targeted therapy” → “hormone therapy”, which may be adjusted or reduced depending on the patient’s condition. It is true that the survival rate of stage 3 breast cancer is lower than that of stage 1 and 2 breast cancer patients. Therefore, it is important to remind everyone that regular breast examination is very important, and once you feel a hard lump that you have doubts about, do not refuse to seek medical treatment because of shyness or fear. With the advanced modern medicine, the cure rate of early stage breast cancer is very high.