In two studies, the estimated risks of developing breast cancer by age 70 years were 55 to 65 percent for women who carry a deleterious mutation in the BRCA1 gene and 45 to 47 percent for women who carry a deleterious mutation in the BRCA2 gene (6,7). Estimates of the lifetime risk of breast cancer for women with Cowden syndrome, which is caused by certain mutations in the PTEN gene, range from 25 to 50 percent (8,9) or higher (10), and for women with Li-Fraumeni syndrome, which is caused by certain mutations in the TP53 gene, from 49 to 60 percent (11). (By contrast, the lifetime risk of breast cancer for the average American woman is about 12 percent.)

Other women who are at very high risk of breast cancer may also consider bilateral prophylactic mastectomy, including:

• those with a strong family history of breast cancer (such as having a mother, sister, and/or daughter who was diagnosed with bilateral breast cancer or with breast cancer before age 50 years or having multiple family members with breast or ovarian cancer)

• those with lobular carcinoma in situ (LCIS) plus a family history of breast cancer (LCIS is a condition in which abnormal cells are found in the lobules of the breast. It is not cancer, but women with LCIS have an increased risk of developing invasive breast cancer in either breast. Many breast surgeons consider prophylactic mastectomy to be an overly aggressive approach for women with LCIS who do not have a strong family history or other risk factors.)

• those who have had radiation therapy to the chest (including the breasts) before the age of 30 years—for example, if they were treated with radiation therapy for Hodgkin lymphoma [Such women are at high risk of developing breast cancer throughout their lives (12).]

Can a woman have risk-reducing surgery if she has already been diagnosed with breast cancer?

Yes. Some women who have been diagnosed with cancer in one breast, particularly those who are known to be at very high risk, may consider having the other breast (called the contralateral breast) removed as well, even if there is no sign of cancer in that breast. Prophylactic surgery to remove a contralateral breast during breast cancer surgery (known as contralateral prophylactic mastectomy) reduces the risk of breast cancer in that breast (2,4,5,13), although it is not yet known whether this risk reduction translates into longer survival for the patient (13). 

However, doctors often discourage contralateral prophylactic mastectomy for women with cancer in one breast who do not meet the criteria of being at very high risk of developing a contralateral breast cancer. For such women, the risk of developing another breast cancer, either in the same or the contralateral breast, is very small (14), especially if they receive adjuvant chemotherapy or hormone therapy as part of their cancer treatment (15,16).

Given that most women with breast cancer have a low risk of developing the disease in their contralateral breast, women who are not known to be at very high risk but who remain concerned about cancer development in their other breast may want to consider options other than surgery to further reduce their risk of a contralateral breast cancer (see Question 7).

What are the potential harms of risk-reducing surgeries?

As with any other major surgery, bilateral prophylactic mastectomy and bilateral prophylactic salpingo-oophorectomy have potential complications or harms, such as bleeding or infection (17). Also, both surgeries are irreversible.

Bilateral prophylactic mastectomy can also affect a woman’s psychological well-being due to a change in body image and the loss of normal breast functions. Although most women who choose to have this surgery are satisfied with their decision, they can still experience anxiety and concerns about body image (18,19). The most common psychological side effects include difficulties with body appearance, with feelings of femininity, and with sexual relationships (19). Women who undergo total mastectomies lose nipple sensation, which may hinder sexual arousal.

Bilateral prophylactic salpingo-oophorectomy causes a sudden drop in estrogen production, which will induce early menopause in a premenopausal woman (this is also called surgical menopause). Surgical menopause can cause an abrupt onset of menopausal symptoms, including hot flashes, insomnia, anxiety, and depression, and some of these symptoms can be severe. The long-term effects of surgical menopause include decreased sex drive, vaginal dryness, and decreased bone density.