Vaginal estrogen therapy is safe for young endometrial cancer survivors, study finds

Despite the increased incidence of endometrial cancer in younger women, there is limited research regarding the safety of local, low-dose vaginal estrogen therapy (ET) for survivors. A new study suggests that this form of estrogen is not only effective in relieving numerous menopause symptoms but also does not seem to increase a woman's risk of cancer recurrence. Study results are published online today in Menopause, the journal of The Menopause Society.

Until recently, all forms of hormone therapy, including local, low-dose vaginal estrogen, had the same black boxed warning as higher-dose, systemic therapies, even though the local, low-dose vaginal estrogen options have a limited, localized effect (meaning there is minimal system absorption). The fear of potential adverse effects may have deterred many women from using vaginal ET, despite its proven benefits in managing a number of menopause symptoms such as vaginal dryness, pain during intercourse, and urinary problems.

Women undergoing treatment for endometrial cancer commonly require hysterectomy with bilateral salpingo-oophorectomy or other therapies such as radiation or chemotherapy that induce early menopause, which is typically associated with worse hot flashes, night sweats, and genitourinary symptoms. The incidence of early onset endometrial cancer in American women aged 50 years and younger has increased steadily from 2.2 to 3.3 per 100,000 women between 2000 and 2019, meaning a lot more women are suffering at a younger age. Because of fears about ET, these women are commonly prescribed nonhormone treatments for their menopause symptoms, with limited efficacy.

A new study based on data from electronic health records and insurance claims from 68 healthcare organizations for more than 2,800 women aged 18 to 51 years diagnosed with endometrial cancer sought to evaluate the use of local, low-dose vaginal ET, along with the outcomes associated with its use in younger survivors of endometrial cancer. The mean ET treatment duration was 1.88 years.

Based on the results, the researchers concluded that vaginal ET initiation is minimal in younger survivors of endometrial cancer (estimated at 5.6%). But those survivors who did have short-term exposure to vaginal ET did not have an elevated risk of endometrial cancer recurrence compared with those women who did not use that treatment option. This is the largest known US study assessing endometrial cancer recurrence with local, low-dose vaginal ET use in survivors of endometrial cancer.

Study results are published in the article "Vaginal estrogen therapy utilization and associated outcomes in younger survivors of endometrial cancer."

Early detection and improved, targeted therapies have led to more women surviving their endometrial cancer diagnoses. However, the sequalae from these life-sparing treatments often result in significant impairment to quality of life and sexual function. Genitourinary symptoms associated with menopause rarely improve without treatment and are exacerbated in the context of abrupt, early menopause. Helping survivors of endometrial cancer to make evidence-based decisions about their care is empowering, especially during a vulnerable time. Expanding treatment options to include local, low-dose vaginal estrogen therapy in this population will have long-lasting benefits."

Dr. Monica Christmas, associate medical director, The Menopause Society