After years of upset, hormone cancellations and denials, now comes more evidence that estrogen replacement therapy does NOT cause breast cancer. Estrogen may even protect against breast cancer. If you find this surprising, read on.
Published in Lancet Oncology, March 7, 2012, the study was an extended, 12-year follow-up of 7,645 women, half of whom had been treated with estrogen for an average of 6 years, the other half with placebo. All of the women had received hysterectomy. Follow-up continued for 6 years after the termination of therapy.
The risk of invasive breast cancer was LOWER (0.27% per year) in women taking estrogen than in women taking placebo, meaning no hormone (0.35% per year). In women who did develop breast cancer, those taking estrogen were less likely to die from it (6 deaths, or 0.009% per year) than women who took placebo (16 deaths, or 0.024% per year). Death from any cause was also lower in the hormone-treated group.
The investigators stated, “Our findings…provide reassurance about breast cancer safety for post-menopausal women with (a) previous hysterectomy who receive unopposed estrogen to reduce climacteric symptoms.”
The study participants did not receive progesterone because they had had hysterectomy. In previous studies reporting an increase in breast cancer incidence in hormone-treated women, non-bioidentical progesterone was employed. Other studies suggested that non-bioidentical progesterone was the culprit causing an increase in breast cancer. In contrast, a protective effect applies to bioidentical progesterone, which in a large French study was associated with a reduced breast cancer incidence.
In our practice we only prescribe bioidentical hormones, including estrogen, progesterone and testosterone. The benefits are so dramatic that we routinely offer bio-identical hormone replacement to women in menopause, and maintain therapy for years, even into the 70s and 80s. Osteoporosis reversal is perhaps the most remarkable effect. Now it appears that prevention of breast cancer may be another benefit, as well as many others.
Allan Sosin MD