Women who have gene mutations that increase the risk of breast and ovarian cancer can substantially reduce their chances of developing—and dying from—those cancers if they have their breasts or ovaries removed preemptively, according to a new study.

Updated August 31, 2010

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By Amanda Gardner

TUESDAY, August 31 (Health.com) — Women who have gene mutations that increase the risk of breast and ovarian cancer can substantially reduce their chances of developing—and dying from—those cancers if they have their breasts or ovaries removed preemptively, according to a new study.

The study, which appears in the Journal of the American Medical Association, confirms that preventive mastectomy and ovary removal can slash the risk of cancer in women carrying the BRCA-1 or BRCA-2 gene mutations, and it suggests that surgery is more effective than rigorous screening at preventing future cancer.

Researchers at 22 cancer centers in the U.S. and Europe followed nearly 2,500 women with BRCA gene mutations for about four years. None of the women who underwent preventive mastectomy developed breast cancer during the study, whereas 7% of the women who opted against the surgery did. (The women who did not have surgery were put on an intensive screening schedule.)

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Meanwhile, just 1% of women who had at least one ovary and fallopian tube removed (a procedure known as salpingo-oophorectomy) were diagnosed with ovarian cancer, compared to 6% of women who didn't have the surgery. The rate of breast-cancer diagnosis was also lower in women who underwent salpingo-oophorectomy (11%) than in those who did not (19%).

In addition, the women who had an ovary and fallopian tube removed cut their risk of dying from ovarian and breast cancer by 79% and 56%, respectively.

The findings confirm "an incredibly important endpoint," says Claudine Issacs, MD, one of the study researchers and the medical director of cancer assessment and risk evaluation at Georgetown Lombardi Comprehensive Cancer Center, in Washington, D.C. "If you have this preventive surgery, it not only decreases the risk of disease but also significantly decreases the risk of death, which is [the] most important thing you're trying to do."

Between 56% and 84% of women with a BRCA mutation will develop breast cancer in their lifetime, while 36% to 63% of women with the BRCA-1 mutation and 10% to 27% of women with the BRCA-2 mutation will develop ovarian cancer, according to estimates cited in the study.

Women who test positive for the BRCA-1 or BRCA-2 mutations generally have three options for managing their risk: body-altering surgery, preventive chemotherapy, or a stepped-up screening regimen that includes frequent mammograms. (Screening techniques are less effective for ovarian cancer than for breast cancer, and doctors usually advocate salpingo-oophorectomy if a woman has completed her family.)

Whether—and when—to have preventive surgery can be a gut-wrenching decision for many women, since surgery can impact both how they look (in the case of mastectomy) and their ability to have a family, says Rob Watson, MD, assistant professor of surgery at the Texas A&M Health Science Center College of Medicine, in Temple.

Some women facing this decision "are very young, and the timing can have a significant effect on body image and reproductive status," Dr. Watson says. "We're trying to help them understand what age is going to be best for them in relation to family planning and body image and some of the other goals they want to achieve."

Women with a BRCA gene mutation are often reluctant to have preventive surgery, despite its proven ability to reduce risk. Just 10% of the women in the study—who were as young as 20—opted for preventive mastectomy, while 38% decided to remove one or both of their ovaries and fallopian tubes.

Salpingo-oophorectomy reduced the risk of ovarian cancer regardless of which BRCA mutation a woman had, or whether she had been previously diagnosed with breast cancer. The procedure also reduced the risk of breast cancer—but only in women who had never been diagnosed with breast cancer before.

"For women to get maximum benefit from oophorectomy in terms of breast-cancer risk, they should have it done prior to the first diagnosis of breast cancer," Dr. Watson says.

Three percent of the women who underwent salpingo-oophorectomy died of any cause (including cancer) during the study, versus 10% of the women who did not have the surgery. The rates of fatal ovarian and breast cancer were lower in women who had the surgery.

"Oophorectomy and mastectomy may be the best and most effective way to reduce their risk," says Len Lichtenfeld, MD, deputy chief medical officer of the American Cancer Society, who was not involved in the new research.

Women who are considering whether to have these surgeries should keep in mind that surgical techniques are more sophisticated and less invasive today than they were 10 or 15 years ago, Dr. Lichtenfeld adds.

"We have considerably improved surgical approaches, especially in terms of breast reconstruction," he says.