The most common type of surgery is modified radical mastectomy-the removal of the entire breast, some of the underarm lymph nodes, and the lining over the chest muscles. In such cases, removal of underarm lymph nodes and radiation therapy to destroy cancer cells that may remain in the breast tissue are part of the primary therapy. Adjuvant hormone therapy deprives cancer cells of the female hormone estrogen, which some breast cancer cells need to grow. Some premenopausal patients may have surgery to remove their ovaries, which are a woman's main source of estrogen. Although this fact sheet focuses on systemic adjuvant therapy, radiation therapy is sometimes used as a local adjuvant treatment.
Radiation therapy is considered adjuvant treatment when it is given before or after a mastectomy.
Such treatment can help destroy breast cancer cells that have spread to nearby parts of the body, such as the chest wall. Radiation therapy is part of primary therapy when it follows breast-sparing surgery. Prognosis refers to the patient's likely outcome after treatment. Prognostic indicators are characteristics of patients and their breast tumors that may help predict whether the disease will recur. When researchers identify such a characteristic, it can be used to help plan treatment.