A mastectomy is a surgical procedure to remove part or all of one or both breasts. It is usually performed to treat or prevent breast cancer. There are several different types of mastectomies, including:

• Partial mastectomy. Removal of some of the breast tissue surrounding the tumor and the lining of the chest muscles beneath it. In some cases, lymph nodes under the arm or in the chest may also be removed.
  
  
• Simple mastectomy. Removal of all of the breast tissue, including the lobules, ducts, fatty tissue and a strip of skin with the nipple and areola.
  
  
• Modified radical mastectomy. Removal of the entire breast and some lymph nodes from under the arm or in the chest.
  

A mastectomy may cure breast cancer and dramatically reduce the likelihood of its return, but there is a chance for the cancer to recur. Breast tissue is widely distributed on the chest wall and can sometimes be found in the armpit and in areas stretching from above the collarbone down to the abdomen. Some of these areas are not within the scope of a mastectomy, and other forms of treatment may be necessary to help ensure that all cancer is treated (e.g., chemotherapy).

Some women may choose to have a prophylactic or preventive mastectomy. This entails surgery to remove one or both breasts to reduce the risk of developing breast cancer. Prophylactic mastectomies may be considered by women who may have had cancer in one breast, have a family history of breast cancer or have a genetic predisposition to the disease.

Mastectomies can be emotionally challenging for women faced with the loss of one or both breasts. For this reason, many women choose to undergo a breast reconstruction that creates an artificial breast closely approximating a natural breast.