- A large Spanish cohort study reaffirms higher fracture risk associated with aromatase inhibitors (AIs) vs tamoxifen (TAM) for hormone receptor-positive (HR+) early breast cancer (eBCa).
- In the subset of AI-treated patients with high risk of fracture, bisphosphonates reduced fracture risk by around 30%.
Why this matters
- Findings suggest the importance of evaluation of, and treatment of, fracture risk with bisphosphonates in AI-treated osteoporotic patients with HR+ eBCa.
- Real-world retrospective primary care cohort (n=36,472) of HR+ eBCa patients treated with AIs or TAM in the Catalonian System for the Development of Research in Primary Care (SIDIAP) database, 2006-2015.
- HRs for fracture were calculated from propensity score-matched patients (HR) and in sensitivity analysis adjusting for competing risk of death (SHR).
- Funding: European Regional Development Funds; National Institute for Health Research; others.
- Fracture risk among postmenopausal women was ~40% higher in AI-treated vs TAM-treated patients (HR, 1.40; 95% CI, 1.05-1.87 and SHR, 1.48; 95% CI, 1.11-1.98).
- In the subset of patients at high risk for fracture with AIs (due to osteoporosis; n=4153), bisphosphonates reduced the fracture risk by ~30% (HR, 0.73; 95% CI, 0.51-1.04 and SHR, 0.69; 95% CI, 0.48-0.98).
- Retrospective, observational design.
- No data on severity or grade of BCa.