Adverse events associated with statin co-use in breast cancer patients: a disproportionality analysis based on the FDA Adverse Event Reporting System

Background: An increasing number of breast cancer patients are using statins concomitantly. However, there are relatively few safety studies on the association between statins and adverse events (AEs) during breast cancer treatment. Objective: This study aims to systematically evaluate the disproportionality signals associated with statin use and the reporting of AEs across different system organ classes (SOCs) in breast cancer patients. Design: This is a pharmacovigilance disproportionality analysis based on the U.S. Food and Drug Administration’s (FDA) Adverse Event Reporting System database. Methods: All AE reports related to breast cancer from the 2004 Q1 to 2024 Q3 were extracted. Disproportionality analysis was performed using reporting odds ratios (RORs) to detect potential safety signals associated with statin use. Multivariate logistic regression model was used as a secondary analysis to adjust for potential confounders, including age, gender, and therapeutic drugs. Results: A total of 237,868 breast cancer-related AE reports were identified, of which 8,223 involved concomitant statin use. Statin use was associated with lower RORs of hepatobiliary (ROR: 0.60, 95% CI: 0.52–0.68), and blood and lymphatic system disorders (ROR: 0.62, 95% CI: 0.57–0.67). In contrast, higher RORs were observed for skin and subcutaneous tissue (ROR: 1.75, 95% CI: 1.67–1.84), psychiatric (ROR: 1.95, 95% CI: 1.82–2.08), renal and urinary (ROR: 2.03, 95% CI: 1.85–2.22), musculoskeletal and connective tissue (ROR: 1.48, 95% CI: 1.40–1.58), infections and infestations (ROR: 1.25, 95% CI: 1.18–1.34), metabolism and nutrition (ROR: 1.25, 95% CI: 1.16–1.35), gastrointestinal (ROR: 1.10, 95% CI: 1.05–1.16), vascular (ROR: 1.26, 95% CI: 1.16–1.37), nervous system (ROR: 1.20, 95% CI: 1.13–1.27), respiratory, thoracic and mediastinal disorders (ROR: 1.07, 95% CI: 1.00–1.14). Conclusion: In breast cancer patients receiving statins concomitantly, specific disproportionality signals were observed across multiple SOCs. These findings highlight the need for individualized monitoring strategies and further mechanistic studies to clarify the underlying pathways and optimize clinical risk management.