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Contradictory Info: Could Estrogen Protect Against Breast Cancer?

Read all the newest reports on Estrogen use in Menopause very carefully. It's confusing, perhaps contradictory to what we've said before, and you can't just flip between blog posts and get a consistent answer! The newest information from the WHI has been released to members of the The North American Menopause Society (NAMS) specifically about the new paper entitled “Health outcomes after stopping conjugated equine estrogens among postmenopausal women with priorhysterectomy: a randomized controlled trial.” It was published today, April 6,2011, in the Journal of the American Medical Association. For your convenience, both the article1 and the accompanying editorial2 are linked here and referenced below.

In this study, young women, meaning those who got hormone therapy as they transitioned through menopause and were just givenconjugated equineestrogens (CEE), had less invasive breast cancer and less coronary heart disease (CHD) all-cause mortality than older women.These are usually women who do not have a uterus, and were thus not given provera or progesterone and had different timing of estrogen. So we think there is both a timing factor and a possible formulation factor to hormone therapy in menopause.

The actual article details results of the Women’s Health Initiative Estrogen-Alone Trial, reflecting a median of 6 years of treatment and an average of 10.7 years of follow-up. The long-term follow-up and post-stopping findings for this trial have not been previously reported. The authors examined health outcomes in10,739 women with prior hysterectomy, comparing those randomized to receive CEE treatment versus placebo.

For the overall study population, there was a significantly (23%) reduced risk of invasive breast cancer among women randomized to CEE versus placebo over the 10.7 years of follow-up. However, younger women (ages 50-59 at enrollment) tended to have much more favorable outcomes on CEE in the areas of heart disease and overall mortality. For other results, please refer to the article itself. For information on whether this can change how you should take hormone therapy: Gab with your Gyno.

1LaCroix AZ, Chlebowski RT, Manson JE et al. Health outcomes after stopping conjugated equine estrogens among postmenopausal women with prior hysterectomy: a randomized controlled trial. JAMA2011;305:1305-1314. 

2Jungheim ES, Colditz GA. Short-term use of unopposed estrogen. JAMA 2011;305:1354-1355.


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