Prophylactic (Risk-reducing) Surgery. Prophylactic surgery involves removing as much of the “at-risk” tissue as possible. Women may choose to have both breasts removed (bilateral prophylactic mastectomy) to reduce their risk of breast cancer. Surgery to remove a woman’s ovaries and fallopian tubes (bilateral prophylactic salpingo-oophorectomy) can help reduce her risk of ovarian cancer.
Removing the ovaries also reduces the risk of breast cancer in premenopausal women by eliminating a source of hormones that can fuel the growth of some types of breast cancer. No evidence is available regarding the effectiveness of bilateral prophylactic mastectomy in reducing breast cancer risk in men with a harmful BRCA1 or BRCA2 mutation or a family history of breast cancer.
Therefore, bilateral prophylactic mastectomy for men at high risk of breast cancer is considered an experimental procedure, and insurance companies will not normally cover it.
Prophylactic surgery does not completely guarantee that cancer will not develop because not all at-risk tissue can be removed by these procedures. Some women have developed breast cancer, ovarian cancer, or primary peritoneal carcinomatosis (a type of cancer similar to ovarian cancer) even after prophylactic surgery.
Nevertheless, the mortality reduction associated with this surgery is substantial: one study showed that women who underwent bilateral prophylactic salpingo-oophorectomy had a nearly 80% reduction in risk of dying from ovarian cancer and a more than 50% reduction in risk of dying from breast cancer.22
Some evidence suggests that the amount of protection that removing the ovaries and fallopian tubes provides against the development of breast and ovarian cancer may differ between carriers of BRCA1 and BRCA2 mutations.23
Chemoprevention. Chemoprevention is the use of drugs, vitamins, or other agents to try to reduce the risk of, or delay the recurrence of, cancer. Although two chemopreventive drugs (tamoxifen and raloxifene) have been approved by the U.S. Food and Drug Administration (FDA) to reduce the risk of breast cancer in women at increased risk, the role of these drugs in women with harmful BRCA1 or BRCA2 mutations is not yet clear.
Data from three studies suggest that tamoxifen may be able to help lower the risk of breast cancer in BRCA1 and BRCA2 mutation carriers24, including the risk of cancer in the opposite breast among women previously diagnosed with breast cancer.25,26
Studies have not examined the effectiveness of raloxifene in BRCA1 and BRCA2 mutation carriers specifically. Oral contraceptives (birth control pills) may lower the risk of ovarian cancer in women with harmful BRCA1 or BRCA2 mutations.27