Bio-identical estrogen is a plant-based hormone that closely approximates a woman's natural estrogen and is believed safer and more natural than traditional estrogen replacement therapy for such menopausal symptoms as hot flashes and vaginal dryness. As you may know, in 2002 the National Institutes of Health (NIH) shut down a huge study on the risks and benefits of post-menopausal hormone replacement therapy because preliminary results revealed an unacceptable risk of breast cancer, strokes and heart attacks. These risks were associated with therapy that included both estrogen and the hormone progestin. Two years later, the NIH shut down another arm of the study that was looking into the benefits and risks of estrogen replacement therapy (no progestin was used) after preliminary findings showed that the hormone increased the risk of stroke. Estrogen alone did not increase the risk of breast cancer, at least not for the duration of the study.
Although I have never believed that menopause is a disease, or that all postmenopausal women need hormone replacement therapy, I have recommended low doses of bio-identical hormones such as Estrace, Bi-Est, and Tri-Est to women who need reliable short-term relief from frequent and intense hot flashes and from vaginal dryness that makes sex uncomfortable. While bio-identical hormones are assumed to be safer than traditional hormone replacement therapy, they still provide estrogen and may increase the risk of breast cancer. To put your personal risk into perspective: If your mother was the only woman in your family to have breast cancer and developed it after menopause, your personal risk is 50 percent higher than what it would be normally. That sounds much more alarming than it is. Here's an example: of all the women age 50 with only one first-degree relative - mother, sister or daughter - who had breast cancer, 9.8 percent will develop the disease by age 80. That means more than 90 percent of those with a single affected relative won't get breast cancer - not bad odds. Compare that with the fact that of all 50 year-old women with no affected relatives, 6.1 percent will develop breast cancer by age 80.
Still, if I were you, I would avoid any form of estrogen. Instead, you could try black cohosh (Cimicifuga racemosa), which appears to be safe for women who have had breast cancer or have a family history of the disease. Studies so far have not found that black cohosh has estrogenic effects. While it seems to work well to quell hot flashes in some women, it doesn't help everyone.
On the conventional medicine front, a study published in the January 2005 issue of Obstetrics and Gynecology found that the antidepressant Effexor seems to be effective in treating hot flashes in healthy women. An earlier study from the Mayo Clinic found that the anti-seizure drug gabapentin relieved the frequency of hot flashes by 66 percent and also lessened their intensity.
Andrew Weil. M.D.