Zoledronic acid for treatment of osteopenia and osteoporosis in women with primary breast cancer undergoing adjuvant aromatase inhibitor therapy

Background: Postmenopausal women with osteoporosis/osteopenia are at increased risk of fracture. Aromatase inhibitors further increase bone loss in these patients. This study evaluates whether zoledronic acid prevents the bone loss expected when these patients initiate letrozole. Patients and methods: Postmenopausal women with estrogen and/or progesterone receptor-positive breast cancer and a bone mineral density (BMD) T-score <-2.0 were given letrozole 2.5. mg/vitamin D 400 international units daily, calcium 500. mg twice daily, and 4. mg zoledronic acid every 6. months. The BMD was assessed at baseline and 1. year. The primary endpoint was the mean change in lumbar spine (LS) BMD at 1. year. Results: Forty-six patients completed 1. year of treatment. LS BMD increased by 2.66% (p=0.01), femoral neck (FN) by 4.81% (p=0.01), and any measured endpoint by 4.55% (p=0.0052). Conclusions: Zoledronic acid prevents bone loss in postmenopausal women with osteoporosis/osteopenia starting letrozole and is associated with improvements in BMD.