Maximizing the Safety of Estrogen Replacement Therapy

The estrogens are a category of hormones used to treat symptoms of menopause such as hot flashes. There is also convincing evidence for a preventive effect on chronic diseases like osteoporosis, heart disease, and cognitive decline. In this post, we’ll shed some light on one of the most misinterpreted topics of estrogen replacement - breast cancer risk.

For most women, estrogens can be used safely with little to no risk of breast cancer. Though, it’s crucial that the correct estrogens are used, at appropriate doses, for an optimal amount of time. Unfortunately, many healthcare providers are misinformed on the safety profile of estrogens. Much of this confusion surrounding breast cancer risk stems from an often-misinterpreted clinical trial called the Women’s Health Initiative (WHI). The WHI trial examined the safety of Prempro - a combination product containing Conjugated Equine Estrogen (Premarin) and Medroxyprogesterone (Provera). Due to the WHI’s findings of a 1.24-fold increased risk of breast cancer, many doctors discontinued treatment of Prempro leaving many patients confused, worried, and without a treatment option for navigating menopausal years.

As time went on, it was recognized the WHI results had a flaw -  women in the treatment group had more risk factors for breast cancer than those in the placebo group resulting in an overestimation of the risk of hormone replacement on breast cancer. After adjusting for this finding, the increased risk of hormone use on breast cancer was no longer significant. Another finding of the WHI was that that when estrogen was used alone, there was no increased risk of breast cancer. This led many researchers to wonder whether the Medroxyprogesterone (Provera) component in the combined product was to blame, not the Conjugated Equine Estrogen (Premarin). In the years to follow other clinical trials examined the effect different progestins have on breast cancer. The reoccurring theme seems to be when bioidentical progesterone is used alongside an estrogen, there is no increased risk of breast cancer. However, when synthetic progestins like Medroxyprogesterone (Provera) are used there is an increased risk of breast cancer. In other words, synthetic progestins increased the risk of breast cancer, while bioidentical progesterone protects against breast cancer.    

How to Use Estrogens Safely

So, can patients using estrogens be confident they won’t develop breast cancer? The answer to this is yes, there does seem to be a safe, or safest, way to use estrogens for most patients. Below, you’ll find 3 strategies maximizing the safety of estrogen replacement. These are commonly prescribed by expert doctors and compounded at Maida Pharmacy Compounding and Wellness.

Topical and Bioidentical Progesterone

When topical bioidentical progesterone is used alongside topical estrogen, there seems to be no increased risk of breast cancer. In fact, breast cancer incidence decreased suggesting a protective and preventive effect of bioidentical progesterone.  

Topical and Bioidentical Estriol

When estriol – a weaker estrogen – is used alongside estradiol, it lessens the proliferative effects of estradiol. In other words, the weaker estrogen – estriol - puts a damper on the more potent estrogen – estradiol. We commonly compound different ratios of estriol: estradiol on a patient-by-patient basis.   Short Duration of Use

If you are concerned with cancer risk, you can be reassured that epidemiologic trials show no risk among past users. In other words, several years of use to manage hot flashes early in menopause is unlikely to cause breast cancer.

Though, there is much confusion around the risk of breast cancer in patients using hormone replacement, for many, estrogens can be used safely with little to no risk of breast cancer. However, it’s crucial that the correct estrogens are used, at appropriate doses, for an optimal amount of time. Our consulting pharmacists are happy to discuss personalized treatment options. Schedule a complimentary consult to learn more about hormone replacement therapy.

Written by

Angelo Maida, PharmD

Compounding Pharmacist at Maida Pharmacy Compounding and Wellness