The Use of Zoledronic Acid to Prevent Cancer-treatment Bone Loss in Post-menopausal Women Receiving Adjuvant Letrozole for Breast Cancer

Post-menopausal breast cancer patients will receive letrozole 2.5 mg daily for the treatment of breast cancer and will be randomized to a treatment group to receive either upfront zoledronic acid 4 mg IV 15-minute infusion every 6 months or delayed start zoledronic acid 4 mg IV 15-minute infusion every 6 months. Delayed start zoledronic acid will be initiated when either the Bone Mineral Density T-score is below -2 Standard Deviations at either the lumbar spine or hip or any clinical fracture unrelated to trauma or an asymptomatic fracture discovered at the month 36 scheduled visit. Letrozole 2.5 mg will be given daily for 5 years.