Definition Surgical removal of the breast to treat diseased breast tissue, usually cancer .
Simple mastectomy is the removal of the breast only.
Modified mastectomy is the removal of the breast and part of the muscles. The breast tissue is removed with the lymph nodes and muscles if necessary. Second opinions are recommended before a radical mastectomy is performed. Breast cancer is the leading cause of death in women age 40 to 44. Screening for breast cancer with X-ray mammography is highly recommended, especially in women over 40.