As with any treatment there are risks and benefits that must be discussed and considered. Use of estrogen in women with current or history of estrogen sensitive cancers is currently not good practice.
For women who would like to take estrogen it is important that she also takes bio identical progesterone as this has been found to be protective against endometrial cancer. If you are considering taking hormone replacement, head over to the National Cancer Institute and take the risk assessment.
The Women’s Health Initiative (WHI) was a large study performed in 2002 looking into whether estrogen only, or estrogen and progesterone hormone therapy was protective for heart disease and strokes in pre-menopausal through post-menopausal women. This initiative showed that peri-menopausal women treated with synthetic hormones were at an increased risk for heart disease, stroke, blood clots, breast cancer, and dementia. However, women up to 79 years of age were permitted to join the study with the median age being 63.
These women were likely 12 years beyond menopause and this data likely contributed to the adverse findings. Additionally, it was found in the study that younger peri-menopausal women had a favorable benefit-to-risk ratio- meaning- the benefits gained by taking hormone replacement therapy to mitigate menopausal symptoms outweighed any risk associated with treatment. Furthermore, the estrogens that were used in the study were synthetic made from horse urine- not bio-identical hormones.
One of the main ramifications from the Women’s Health Initiative was many symptomatic women were denied hormone replacement therapy- likely unnecessarily. Luckily, studies have subsequently re-analyzed the WHI data and found that breast cancer rates actually decreased in estrogen only treatment groups.