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Hormone Replacement Therapy Doesn’t Seem to Increase Risk in Women With Abnormal BRCA1 Gene

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A small study found that postmenopausal women who have an abnormal BRCA1 gene who used combination hormone replacement therapy (HRT) had the same risk of developing breast cancer as women with an abnormal BRCA1 gene who didn't use HRT.

Combination HRT includes both estrogen and progesterone. Women with an abnormal BRCA1 gene who used estrogen-only HRT had a slightly lower risk of breast cancer compared to women with an abnormal BRCA1 gene who didn't use HRT.

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 is also increased. Abnormal BRCA1 and BRCA2 genes are found in 5% to 10% of all breast cancer cases in the United States.

Because of their risk of breast cancer is higher, many premenopausal women with an abnormal breast cancer gene choose to have their ovaries removed (a procedure called oophorectomy). Oophorectomy can lower the risk of BOTH breast and ovarian cancer by quite a bit. Removing the ovaries causes a sudden drop in estrogen levels. While this helps lower breast cancer risk, it also can cause menopausal symptoms, such as hot flashes. Some women may consider using HRT after oophorectomy to ease menopausal symptoms, but may be concerned that HRT may increase breast cancer risk.

Research has shown that HRT, especially combination HRT, increases the risk of breast and ovarian cancer, as well as heart attack and stroke. Still, the side effects of menopause can dramatically reduce some women's quality of life. These women have to weigh the benefits of HRT against the risks. Using HRT for the shortest time possible is one way to minimize the risks. The women in this study used HRT for 3 to 4 years.

Doctors who reviewed this study said because the study is so small, the results aren't definitive enough to say for certain that women with an abnormal breast cancer gene who use HRT don't increase their breast cancer risk.

If you're premenopausal woman with an abnormal breast cancer gene, you may be considering oophorectomy to reduce your risk. And you also may be worried about developing menopausal symptoms after surgery. Those concerns are understandable, but try not to let them shift your focus from making the best decisions for your health. If you've already had your ovaries removed and are having menopausal symptoms, you may be considering HRT but are worried about the risks.

In either case, you and your doctor should carefully consider both the risks and benefits of using HRT. Together you can decide if HRT -- or another treatment to ease menopausal side effects -- might be right for you. If you decide to use HRT, use it for the shortest time possible, consider using estrogen-only HRT, and try to make other healthy lifestyle choices that can lower your breast cancer risk. And remember, during and after HRT make sure to follow the breast cancer screening plan recommended by your doctor for your specific risks and situation.

You can read more about approaches to help ease hot flashes on the Breastcancer.org All About Hot Flashes page.

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