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Clarity on hormones and cancer

On synthetic hormones (like Premarin) vs. natural or  bioidentical hormones.

Since the 2002 report known as The Women’s Health Initiative (WHI) Trial, Prempro sales have fallen to $161 million annually and more than 10,000 lawsuits have been filed against Pfizer by women, who declared the company’s HRT drug lead to their development of breast cancer and other health ailments. Pfizer Inc. recently set aside $772 million to settle these cases.

Hormone replacement therapy (HRT)– a $2.2 billion industry, has been promoted by the medical establishment as a means to reduce vasomotor symptoms and decrease postmenopausal health risks. During the 1990’s, Pfizer and Wyeth had a strong hold on the HRT industry by selling Premarin, Provera, and Prempro (a combination of the two) to more than six million women.

Fears of Hormones and Cancer– It wasn’t until 2002 that the WHI trial found these synthetic hormones increased breast cancer, heart disease, and stroke risks among menopausal women. Researchers admonished women to stop taking HRT, while critics asserted these results were inaccurate declaring HRT benefits outweighed the risks. With two opposing views, confusion escalated among providers and patients.
Re-analysis of the WHI data and findings from other studies demonstrated that the health risks did not apply to women under 60 years old. While breast cancer risks increased when estrogen and progestin were combined, further analysis of the WHI trial found that the estrogen-only group didn’t have an increase in breast cancer risks. In fact, breast cancer risks decreased in this group.

Clearing the Confusion– A review of the WHI trial may clarify the risks of synthetic HRT, but it doesn’t mean these hormones are harmless. According the National Institutes of Health, long-term use is not recommended, but taking HRT at the lowest possible dose for the shortest amount of time can provide some benefit for menopausal women, including a reduction in osteoporosis risks.
This statement, combined with media attention and the WHI study itself, have sparked extensive concern that hormones are harmful and should be taken for the shortest time necessary to control perimenopausal symptoms. Dr. Neal Rouzier has clarified this concern through intensive study, stating that, “I agree with this statement ONLY if the hormones are synthetic, like Premarin and Provera.

The combination Premarin and Provera have demonstrated an increased risk of breast cancer, strokes and heart attacks. However, do not extrapolate the harm of synthetic hormones to bioidentical HRT. Natural progesterone has never been demonstrated, in any study, to increase these risks whereas Provera has definitely been shown to increase these risks. Natural progesterone has been shown to decrease the risk of breast cancer, whereas Provera increases breast cancer in every study to date. Natural estradiol has been proven to not have the clotting or inflammatory properties as does Premarin.”

The Natural Answer– Fortunately, there are sharply contrasting alternatives to synthetic HRT which actually have shown to help protect against cancer. *Bioidentical HRT is a substantially effective treatment for menopausal symptoms that also protects women from the many other risks associated with low hormone levels. Over 50 years of studies indicate that restoring hormones to premenopausal levels protects women from health risks and encourages well-being. Bioidentical hormones are the safest and most effective way to ensure optimal hormone levels. Bioidentical hormones should not be confused with synthetic HRT, as they are far superior to their synthetic counterpart.


Campagnoli C, Clavel-Chapelon F, Kaaks R, Peris C, Berrino F. Progestins and progesterone in hormone replacement therapy and the risk of breast cancer. J Steroid Biochem Mol Biol. 2005; 96(2):95-108.

Gambrell RD. The Women’s Health Initiative reports: Critical review of the findings. The Female Patient. 2004; 29:25-41.

Holtorf K. The bioidentical hormone debate: are bioidentical hormones (estradiol, estriol, and progesterone) safer or more efficacious than commonly used synthetic versions in hormone replacement therapy? Postgrad Med. 2009 Jan;121(1):73-85.

Howard L. Pfizer to settle remaining hormone therapy lawsuits for $300 million minimum. Retrieved on May 26, 2011 from

Million Women Study Collaborators. Breast cancer and hormone-replacement therapy in the Million Women Study, Lancet. 2003;362:419–427.

Rossouw E. Anderson GL, Prentice RL, et al. Risks and benefits of estrogen plus progestin in healthy postmenopausal women: principal results from the Women’s Health Initiative randomized controlled trial, JAMA. 2002;288:321–333.


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