Neoadjuvant therapy is given to breast cancer patients whose cancers are relatively large or have spread to lymph nodes or both. The primary goal of this treatment is to prevent the cancer from coming back (recurring) elsewhere in the body, but if it makes the cancer in the breast and lymph nodes shrink it might be easier to remove. This could allow a patient to have a lumpectomy instead of a mastectomy and reduce the number of lymph nodes that the surgeon has to remove. In some cases, the neoadjuvant therapy works so well that it kills all of the cancer in the breast and lymph nodes. This is referred to as a pathologic complete response (pCR). Patients who achieve a pCR have a much lower risk of the cancer recurring elsewhere in their bodies.