Safety of Vaginal Estrogen Therapy for Genitourinary Syndrome of Menopause in Women With a History of Breast Cancer.
Level 3 - non-randomized controlled study
Retrospective propensity-matched cohort study using claims data
PubMed 37535961 · doi:10.1097/AOG.0000000000005294
What was done
Researchers queried the TriNetX Diamond Network claims database (2009–2022) to evaluate whether vaginal estrogen therapy increases breast cancer recurrence in women with genitourinary syndrome of menopause (GSM) and a history of breast cancer diagnosed within the prior 5 years. Patients with active disease within 3 months before GSM diagnosis were excluded. The exposed group included women with three or more vaginal estrogen prescriptions; the control cohort included women with GSM and no vaginal estrogen prescriptions. Breast cancer recurrence was defined using surrogate billing codes (mastectomy, radiation, chemotherapy, or secondary malignancy) within 3 months to 5 years following treatment initiation. Propensity-score matching and a subgroup analysis for estrogen receptor-positive (ER+) disease were conducted.
What was found
The overall cohort included 42,113 women with GSM after breast cancer, of whom 5.0% received vaginal estrogen. A subgroup of 10,584 women had confirmed ER+ breast cancer, with 3.9% receiving vaginal estrogen. Breast cancer recurrence risk was comparable between vaginal estrogen users and non-users across all breast cancer types (risk ratio 1.03, 95% CI 0.91–1.18) and within the ER+ subgroup (risk ratio 0.94, 95% CI 0.77–1.15).
Why it matters
These data provide real-world evidence that localized vaginal estrogen for GSM symptoms does not appear to elevate 5-year breast cancer recurrence risk, even among patients with hormone-receptor-positive disease.
Limits
As an observational claims-based study, recurrence was captured via surrogate treatment and diagnostic codes rather than adjudicated clinical records. Follow-up was limited to 5 years, medication adherence beyond filled prescriptions could not be confirmed, and ER status was available for only a subset of patients.
Cited by
- supports The medical consensus is that women with a past history of breast cancer who cannot use systemic estrogen therapy may safely be candidates for vaginal estrogen use.