Surgery to Reduce the Risk of Breast Cancer (Fact Sheet)

What kinds of surgery can reduce the risk of breast cancer?

Two kinds of surgery can be performed to reduce the risk of breast cancer in a woman who has never been diagnosed with breast cancer but is known to be at very high risk of the disease.

A woman can be at very high risk of developing breast cancer if she has a strong family history of breast and/or ovarian cancer, a deleterious (disease-causing) mutation in the BRCA1 gene or the BRCA2 gene, or a high-penetrance mutation in one of several other genes associated with breast cancer risk, such as TP53 or PTEN (see Question 3).

The most common risk-reducing surgery is bilateral prophylactic mastectomy (also called bilateral risk-reducing mastectomy). Bilateral prophylactic mastectomy may involve complete removal of both breasts, including the nipples (total mastectomy), or it may involve removal of as much breast tissue as possible while leaving the nipples intact (subcutaneous or nipple-sparing mastectomy). Subcutaneous mastectomies preserve the nipple and allow for more natural-looking breasts if a woman chooses to have breast reconstruction surgery afterward. However, total mastectomy provides the greatest breast cancer risk reduction because more breast tissue is removed in this procedure than in a subcutaneous mastectomy (1).

Even with total mastectomy, not all breast tissue that may be at risk of becoming cancerous in the future can be removed. The chest wall, which is not typically removed during a mastectomy, may contain some breast tissue, and breast tissue can sometimes be found in the armpit, above the collarbone, and as far down as the abdomen—and it is impossible for a surgeon to remove all of this tissue. 

The other kind of risk-reducing surgery is bilateral prophylactic salpingo-oophorectomy, which is sometimes called prophylactic oophorectomy. This surgery involves removal of the ovaries and fallopian tubes and may be done alone or along with bilateral prophylactic mastectomy in premenopausal women who are at very high risk of breast cancer. Removing the ovaries in premenopausal women reduces the amount of estrogen that is produced by the body. Because estrogen promotes the growth of some breast cancers, reducing the amount of this hormone in the body by removing the ovaries may slow the growth of those breast cancers.

How effective are risk-reducing surgeries?

Bilateral prophylactic mastectomy has been shown to reduce the risk of breast cancer by at least 95 percent in women who have a deleterious (disease-causing) mutation in the BRCA1 gene or the BRCA2 gene and by up to 90 percent in women who have a strong family history of breast cancer (2-5).

Bilateral prophylactic salpingo-oophorectomy has been shown to reduce the risk of ovarian cancer by approximately 90 percent and the risk of breast cancer by approximately 50 percent in women at very high risk of developing these diseases (1).

Which women might consider having surgery to reduce their risk of breast cancer?

Women who inherit a deleterious mutation in the BRCA1 gene or the BRCA2 gene or mutations in certain other genes that greatly increase the risk of developing breast cancer may consider having bilateral prophylactic mastectomy and/or bilateral prophylactic salpingo-oophorectomy to reduce this risk.