Most inherited cases of breast cancer are associated with two abnormal genes: BRCA1 (BReast CAncer gene one) and BRCA2 (BReast CAncer gene two). Women with an abnormal BRCA1 or BRCA2 gene have up to an 85% risk of developing breast cancer by age 70. Their risk of ovarian cancer also is higher than average.
Abnormal BRCA1 and BRCA2 genes are found in 5% to 10% of all breast cancer cases in the United States.
One aggressive way to lower the risk of both cancers in women with an abnormal BRCA1 or BRCA2 gene is to remove the ovaries and fallopian tubes. This is called prophylactic (protective) salpingo-oophorectomy (oo-for-EK-tuh-mee).
The study reviewed here found that removing the ovaries and fallopian tubes of women with an abnormal BRCA1 or BRCA2 gene reduces breast cancer risk by 50% and ovarian cancer by 80%. The researchers combined the results of 10 studies looking at breast and/or ovarian cancer in women with an abnormal BRCA1 or BRCA2 gene.
Removing the ovaries and fallopian tubes to reduce breast cancer risk offers benefits only if the surgery is done before menopause. Removing the ovaries before menopause significantly reduces the level of estrogen in a woman's body. Because some breast cancers require estrogen to grow, removing the ovaries may slow or even stop the growth of breast cancer cells.
Removing the ovaries and fallopian tubes to reduce ovarian cancer risk can be done before or after menopause.
Women with an abnormal BRCA1 or BRCA2 gene often are advised to have their ovaries removed by age 35 or as soon as they're done having children. But this study found that the age at which surgery should be recommended isn't clear because the ages of the women in the studies were all very similar. More research is planned to figure out the best timing for ovary removal surgery, as well as the health consequences of the surgery.
If you learn that you have an abnormal BRCA1 or BRCA2 gene, talk your doctor about ALL of the options that can lower your risk for both breast and ovarian cancer. Removing the ovaries is only one option. Some women may decide to have prophylactic removal of both breasts. There are also medicine options, depending on your menopausal status. Medicines can be used to shutdown the ovaries and hormonal therapies can block estrogen effects or lower estrogen production. Together, you and your doctor can decide on the best risk reduction plan for your unique situation.
PHILADELPHIA, Jan. 13 (MedPage Today) -- Removing the fallopian tubes and ovaries of BRCA1/2 mutation carriers cuts their risk of breast cancer in half, a meta-analysis showed.
Breast cancer risk was reduced by about 50% ovarian/fallopian tube by about 80% in patients who had the mutation, Timothy Rebbeck, Ph.D., of the University of Pennsylvania, and colleagues reported online in the Journal of the National Cancer Institute.
"The consistency of these findings across the included studies confirms the strong association of risk-reducing salpingo-oophorectomy with reduced risks of breast and ovarian cancer in BRCA1 or BRCA2 mutation carriers," the researchers said.
The procedure is typically performed in BRCA1/2 mutation patients, sometimes in conjunction with mastectomy, to reduce the risk of breast cancer.
But the magnitude of the risk reductions has been unclear.
So the researchers conducted a meta-analysis of 10 studies that investigated breast or gynecologic cancer outcomes in BRCA1/2 mutation carriers.
They found that salpingo-oophorectomy was associated with a statistically significant reduction in risk of breast cancer in BRCA1/2 mutation carriers (HR 0.49, 95% CI 0.37 to 0.65).
Similar risk reductions were observed separately in BRCA1 mutation carriers (HR 0.47, 95% CI 0.35 to 0.64) and in BRCA2 mutation carriers (HR 0.47, 95% CI 0.26 to 0.84).
The procedure was also associated with statistically significant reduction in the risk of BRCA1/2-associated ovarian or fallopian tube cancer (HR 0.21, 95% CI 0.12 to 0.39).
However, the researchers said that a few questions remained, particularly the potentially larger risk reduction associated with salpingo-oophorectomy in BRCA2 mutation carriers. Some studies did not find this association, so the researchers said this should be investigated in larger follow-up studies.
They also noted that the effect of age at the time of the procedure on risk reduction remains unresolved because studies used for the review that looked at this effect were done in a small population.
The researchers said that although the procedure has become the standard of care for cancer risk reduction in women who have inherited BRCA1/2 mutations, mastectomy has shown a "substantially reduced breast cancer risk."
The researchers also warned that residual cancer risk remains after the procedure, so "additional cancer risk reduction and screening strategies are required to maximally reduce cancer incidence and mortality in this high-risk population."
In an accompanying editorial, Mark H. Greene, M.D., and Phuong L. Mai, M.D., of the National Cancer Institute, said the findings suggest salpingo-oophorectomy had resulted in "substantial reductions in cancer incidence and perhaps mortality among BRCA mutation carriers ? [and has] catalyzed major advances in our understanding of ovarian carcinogenesis."
The study was funded by grants from the National Institutes of Health, the Department of Defense Breast Cacner Research Program, the Cancer Genetics Network, the Eileen Genet Fund, and the Project Hope Fund for Ovarian Cancer Research and Education.
A co-author reported receiving fees for legal defense work of behalf of Wyeth.
The researchers reported no other conflicts of interest.
Journal of the National Cancer Institute Source reference: Rebbeck TR, et al "Meta-analysis of risk reduction estimates associated with risk-reducing salpingo-oophorectomy in BRCA1 or BRCA2 mutation carriers"
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