A mastectomy is surgery to remove a breast. It is performed either to treat or to prevent breast cancer . Only high-risk patients have surgery to prevent cancer. There are four main types: Total mastectomy - removal of breast tissue and nipple Modified radical mastectomy - removal of the breast, most of the lymph nodes under the arm and often the lining over the chest muscles Lumpectomy - removal of a breast tumor and a small amount of surrounding tissue, usually including most of the underarm lymph nodes Radical mastectomy - the removal of the breast, lymph nodes and chest muscles. This is no longer common Which surgery you have depends on the stage of cancer, size of the tumor, size of the breast and whether the lymph nodes are involved. Many women have breast reconstruction to rebuild the breast after a mastectomy.