SAT-139 Testosterone Therapy and Breast Cancer Risk in Postmenopausal Women: A Systematic Review and Meta-Analysis

Abstract Disclosure: S.G. Ribeiro: None. K.O. Eskandar: None. A.R. Do Amaral: None. A.D. Francisco: None. J.C. Neto: None. E.B. Oliveira: None. K. Woodhams: None. Background: Testosterone therapy is increasingly utilized in postmenopausal women to manage symptoms and enhance quality of life. However, concerns persist regarding its potential association with breast cancer risk. This meta-analysis critically evaluates the incidence of breast cancer in postmenopausal women receiving testosterone therapy compared to population-based controls.Objective: To assess the association between testosterone therapy and breast cancer risk in postmenopausal women compared to population-based controls.Methods: A systematic review and meta-analysis were conducted to assess breast cancer incidence in postmenopausal women using testosterone therapy. A comprehensive search of PubMed, Cochrane, and Embase was conducted to identify randomized, non-randomized, and observational studies.Pooled risk ratios (RRs), odds ratios (ORs), and 95% confidence intervals (CIs) were calculated using a random-effects model. Statistical significance was assessed via p-values for overall effect. Results: A total of 5,747 postmenopausal women receiving testosterone therapy were analyzed, with a follow-up ranging from 4.4 to 10 years. Breast cancer incidence in testosterone users was consistently lower compared to the population-based cancer incidence data, with individual study risk ratios (RRs) ranging from 0.530 to 0.638. The overall meta-analysis confirmed this reduction, with a pooled RR of 0.592 (95% CI: 0.381-0.920; p = 0.02; I² = 21%), indicating a statistically significant decrease in breast cancer risk among postmenopausal women receiving testosterone therapy. Conclusions: In this meta-analysis of observational studies, testosterone therapy was not associated with an increased risk of breast cancer. Instead, pooled estimates suggest a statistically significant reduction in risk (p = 0.02 for RR, p = 0.04 for OR). The data indicate that testosterone therapy may be protective, but due to the observational nature of the included studies, further randomized controlled trials (RCTs) are necessary for definitive conclusions. Presentation: Saturday, July 12, 2025