Abstract PS1-05-26: Vaginal estrogen versus non-hormonal moisturizer for breast cancer survivors on aromatase inhibitor therapy: a randomized, controlled trial

Abstract Background: Among post-menopausal breast cancer survivors, more than 60% experience atrophic vaginitis, often resulting in impaired quality of life and sexual dysfunction. Nonetheless, vaginal dryness is commonly an unmet need among breast cancer survivors. While vaginal estrogen is a proven, effective treatment for atrophic vaginitis, it has not been adequately studied in Estrogen Receptor-positive (ER+) breast cancer survivors. Methods: In this randomized, controlled, unblinded clinical trial, we enrolled ER+ breast cancer survivors on adjuvant aromatase inhibitor (AI) therapy who were suffering from atrophic vaginitis. Women were assigned to receive either Replens® (a non-hormonal vaginal moisturizer) or vaginal estrogen. Based on patient preference, patients randomized to the estrogen arm chose between 6 months of Vagifem® vaginal tablets (10 mcg daily for the first 2 weeks, then twice a week thereafter) or Estring® vaginal ring (2 mg, placed every 3 months). We tested serum estradiol levels by tandem mass spectrometry (TMS) at several time points in the estrogen arm, and only at baseline 2025 Dec 9-12; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2026;32(4 Suppl):Abstract nr PS1-05-26.