Economic evaluation of zoledronic acid for the prevention of osteoporotic fractures in postmenopausal women with early-stage breast cancer receiving aromatase inhibitors in the UK.

BACKGROUND Aromatase inhibitors are used as adjuvant therapy for breast cancer (BC) and are associated with accelerated bone loss. Zoledronic acid (ZOL) prevents aromatase inhibitor-associated bone loss (AIBL) in postmenopausal women with BC. This analysis assessed the cost-effectiveness of ZOL for prevention of fractures in postmenopausal women with BC. MATERIALS AND METHODS A Markov model was developed to project lifetime incidence of fractures, quality-adjusted life years (QALY), and costs as a function of bone mineral density (BMD) for women with early-stage BC receiving letrozole alone or with ZOL. Two strategies of ZOL therapy were compared with no treatment: starting ZOL treatment only when BMD levels decreased ('delayed ZOL') and starting ZOL simultaneously with letrozole therapy ('upfront ZOL'). RESULTS Delayed ZOL therapy was estimated to cost 16,069 pounds per QALY, when compared with not administering bisphosphonates for AIBL prevention. The corresponding cost per QALY gained for upfront ZOL versus no treatment was estimated at 21,973 pounds. The cost-effectiveness ratio for upfront versus delayed therapy was estimated at 24,868 pounds per QALY gained. CONCLUSION Both delayed and upfront therapy with ZOL for the prevention of AIBL and fractures in BC patients in the UK appear to result in highly acceptable cost-effectiveness ratios.