Vaginal Estrogen for Women with Breast Cancer

Reviewing the data for informed decision making

There are millions of women with breast cancer who also experience genitourinary syndrome of menopause (GSM), and lack of treatment for these symptoms can be a major quality of life issue. I regularly see women who tell me they have already had so much taken away from them that living with vaginal dryness, irritation, and pain with sexual activity creates yet another level of trauma.

(For a review on GSM, head to this post, and the complete listing of the posts in the hormone therapy guide can be found here).

While GSM can be very uncomfortable and problematic for many women, those with breast cancer often suffer more. For those who need chemotherapy before they reach menopause, GSM starts earlier, as chemotherapy can trigger menopause. In addition, women with hormone receptor-positive breast cancer, who are 79-84% of women with breast cancer, often receive hormone medications that reduce estrogen or block its effects. One class of these drugs stops the ovaries from producing estrogen, so the net effect on the body is the same as menopause. Another common medication is tamoxifen, a selective estrogen receptor modulator or SERM, which can have varying effects on the vagina; it sometimes acts like estrogen but other times acts like an anti-estrogen resulting in GSM. Finally, aromatase inhibitors, or AIs, block the enzyme needed to produce estradiol in every tissue. It’s not surprising that women who take AIs often have severe GSM. These medications are typically taken for five to ten years.

For many years, doctors were hesitant to prescribe vaginal estrogen for women with breast cancer due to concerns about the estrogen, which, if absorbed, might stimulate the growth of cancer for those with estrogen-receptor-positive tumors. However, we now have more data on how much estrogen is absorbed from these products (covered in detail in this post), and there are now several observational studies, so we are in a better position to discuss these therapies for women with breast cancer.

Hormone Receptor Negative Breast Cancer