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The following is a summary of “Vaginal estrogen use in breast cancer survivors: a systematic review and meta-analysis of recurrence and mortality risks,” published in the March 2025 issue of American Journal of Obstetrics & Gynecology by Beste et al. 

Researchers conducted a retrospective study to estimate the risk of breast cancer recurrence, breast cancer-specific mortality, and overall (OA) mortality among survivors of breast cancer who received vaginal estrogen therapy for genitourinary syndrome of menopause.  

They searched Google Scholar, PubMed, EMBASE, CINAHL, NCBI, and Science Direct from database inception to April 6th, 2024. A secondary search was performed on September 26th, 2024, using Google Scholar, PubMed, EMBASE, CINAHL, and Science Direct. Studies reporting breast cancer recurrence, defined per individual review criteria, were included, 3 reviewers assessed studies based on eligibility criteria. The primary outcome was breast cancer recurrence, while secondary outcomes included breast cancer-specific mortality and OA mortality. Pooled unadjusted odds ratios with 95% CI were calculated using a random-effects model. The 95% prediction intervals estimated the range for future individual values. The fragility index was calculated to assess the robustness of pooled estimates.  

The results showed that out of 5,522 identified articles, 8 observational studies were included. The use of vaginal estrogen in individuals with a history of breast cancer was not linked to a higher risk of breast cancer recurrence (6 articles, 24,060 individuals, odds ratio 0.48; 95% confidence interval 0.23–0.98). Breast cancer-specific mortality did not increase with vaginal estrogen use (4 articles, 61,695 individuals, odds ratio 0.60; 95% confidence interval 0.18–1.95). Additionally, there was no rise in OA mortality among survivors of breast cancer using vaginal estrogen (5 articles, 59,724 individuals, odds ratio 0.46; 95% confidence interval 0.42–0.49).  

Investigators concluded that vaginal estrogen use in survivors of breast cancer did not correlate with elevated risks of recurrence, breast cancer-specific mortality, or OA mortality. 

Source: ajog.org/article/S0002-9378(24)01126-8/abstract