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Ovary Removal, Mastectomy Cut Cancer Rates in High-Risk Women
Women with genes that predispose them to breast and ovarian cancer may get improved guidance from a study that clarifies how much they may reduce their risk by removing their ovaries or breasts.
None of the 247 women who had a mastectomy developed breast cancer after three years compared with 7 percent of 1,372 women who didn’t have the surgery, according to the research published today in the Journal of the American Medical Association. Those who had their ovaries and fallopian tubes taken out, and had not had previous breast cancer, reduced their risk of ovarian cancer by about 70 percent, said the study’s senior author, Timothy Rebbeck.
Hundreds of thousands of women in the U.S. carry genetic mutations, called BRCA1 and BRCA2, that give them a higher risk for cancers of the breast and ovaries, though an exact number isn’t known, Rebbeck said. Based on today’s study, any woman who tests positive for the genes should consider removing her ovaries and fallopian tubes to prevent ovarian and breast cancer, he said. Those only seeking to prevent breast cancer may want to consider other options first before choosing mastectomy, he said.
“It’s a big decision to remove healthy breasts and ovaries. It’s important to have good estimates to help women and clinicians make appropriate decisions about prevention,” said Rebbeck, a professor of epidemiology at the University of Pennsylvania in Philadelphia in an Aug. 27 telephone interview. “If you want to prevent ovarian cancer, this is your only choice.”
Early Detection Difficult
Ovarian cancer is difficult to detect early, because symptoms may not occur until the disease is advanced, according to the National Institutes of Health. In breast cancer, mammograms and magnetic resonance imaging, or MRI, allow for early detection, while medicines like tamoxifen can help prevent the disease, Rebbeck said.
Women who have the gene mutations have a 56 percent to 84 percent higher lifetime risk of breast cancer compared with those who don’t have the gene variants, the authors wrote. Those with BRCA1 mutations have a 36 percent to 63 percent increased chance of developing ovarian cancer, while women with the BRCA2 mutation have a 10 percent to 27 percent risk of ovarian cancer.
Today’s study is the largest to show how much preventive surgery reduces the risk of developing cancer in women with these gene mutations.
22 Centers
The researchers included 2,482 women in the study who had BRCA1 or BRCA2 mutations at 22 clinical and research genetics centers in North American and Europe.
Among those who had their ovaries and fallopian tubes removed, none with the BRCA2 mutation had ovarian cancer over the six years of follow up. In those getting the surgery with BRCA1, 10 of 681, or 1.5 percent, developed a nearby abdominal malignancy called peritoneal cancer, the researchers found. That compares with 7.6 percent of women with the BRCA1 mutation and 3.3 percent of women with BRCA2 who didn’t have the surgery and developed ovarian cancer.
The researchers also analyzed their cases in detail to see if their history of any previous breast cancer influenced how much their risk was reduced if they got preventive mastectomy or ovary removal.
Those with the BRCA1 mutation who had their ovaries and fallopian tubes removed reduced their risk of ovarian cancer by 70 percent if they didn’t have a previous diagnosis of breast cancer and by 85 percent if they did have a prior breast cancer, the authors said.
Ovary Removal Benefits
Having the ovary-removal surgery also decreased the women’s chance of breast cancer in those who never had the disease before -- by 37 percent in women with the BRCA1 mutation and 64 percent in those with the BRCA2 mutation. The risk of breast cancer is reduced by the surgery because hormones that raise the chance of developing the disease are eliminated when a woman’s ovaries are removed, Rebbeck said.
“We’re now beginning to fine tune the information we have for women,” Rebbeck said.
Future studies need to look at what effect removal of the ovaries and fallopian tubes have on bone and heart health and depression because the surgery puts women into early menopause, Rebbeck said. Researchers also need to look at the impact of hormone replacement therapy that women may choose following the surgery has on their breast cancer risk, he said.
The study was funded by the U.S. Public Health Service and others including state and federal agencies.
To contact the reporter on this story: Nicole Ostrow in New York at nostrow1@bloomberg.net.
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