Mastectomy is a surgical process performed to remove a woman's breast. This is done either as a prevention or a treatment to breast cancer.

Mastectomy may be further classified into four types: total mastectomy, modified radical mastectomy, lumpectomy and radical mastectomy. In total mastectomy, the breast tissue is removed. There are four sub-types of total mastectomy: the traditional, the skin-sparing, the nipple-sparing and the total skin-sparing. In the traditional total mastectomy, a portion of the skin that includes the areolar complex is removed by the surgeon. The outcome of this type of mastectomy is a flat chest. In skin-sparing total mastectomy, aside from the breast tissue, the nipple and the areola are also removed from the breast. In nipple-sparing total mastectomy, an S-shaped incision is made around the area of the nipple but the areola remains undamaged. Lastly, in total skin-sparing mastectomy, only the breast tissue is removed. The skin, the nipple, the areola and the other underlying parts of the breast are left behind.

The other type of mastectomy, which is the modified radical mastectomy, is the removal of the breast together with axillary nodes. The axillary nodes are the lymph nodes found in the armpit. In lumpectomy, the breast tumor and a bit of the surrounding tissue are removed. In radical mastectomy, the breast, all of the axillary nodes and the other muscles of the pectoral wall are removed. This type of procedure is rarely done nowadays.