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Women’s Health Initiative Study Suggests Women Who Took Combination Hormone Replacement Therapy Have Higher Risk of Breast Cancer

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The Women's Health Initiative (WHI) was a very large study that had more than 15,000 participants. The WHI helped doctors understand the relationship between increased breast cancer risk and using combination hormone replacement therapy (HRT) to manage menopausal side effects. Combination HRT has both estrogen and progesterone.

New WHI results show that the women who took combination HRT were more likely to be diagnosed with breast and lung cancer after they quit taking the HRT than women who got a placebo (a sugar pill).

The WHI also found that women who took combination HRT had a higher risk of having a heart attack or stroke while on HRT. After the women stopped taking combination HRT, their risk for heart problems was similar to the women who took a placebo instead of the combination HRT.

Menopausal side effects can dramatically reduce some women's quality of life. These women have to weigh the benefits of HRT against the risks. If you're having severe hot flashes or other menopausal side effects and are considering taking HRT, talk to your doctor about how you can minimize your breast cancer risk. Be sure to discuss the pros and cons of different types of HRT and how you can take HRT for the shortest time possible.

Two points that you might want to discuss with your doctor:

  • Estrogen-only HRT appears to increase breast cancer risk less than combination HRT.
  • Research has found that using combination HRT for fewer than 3 years didn't significantly increase breast cancer risk.

Together, you and your doctor can decide if HRT or another treatment for the side effects of menopause might be right for you. If you do decide to use HRT, try to make healthy lifestyle choices that can lower your breast cancer risk. During and after HRT, make sure to follow the recommendations for breast cancer screening, including monthly breast self-exams, annual mammograms, and physical examinations by your doctor.

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