Efficacy and Safety of Monthly Minodronate Therapy in Postmenopausal Breast Cancer Patients Receiving Aromatase Inhibitors

Background/Aim: Post-menopausal breast cancer (BC) patients who receive adjuvant aromatase inhibitor (AI) therapy may be at increased risk of bone loss, osteoporosis, and bone fracture. We aimed to evaluate the efficacy and safety of oral bisphosphonate minodronate in preventing bone loss complications. Patients and Methods: Patients receiving AI and 80% of those with suboptimal bone mineral density (BMD) were prescribed monthly oral minodronate 50 mg every 4 weeks for 72 weeks. BMD, bone metabolism markers, incidence of bone fractures, medication compliance, and other adverse events (AE) were examined every 24 weeks following administration. Results: Fifty postmenopausal BC patients with a median age of 64.0 years were enrolled. The mean value of lumbar spine BMD was higher than that of the value before the minodronate administration at each observation point. Before and after the treatment, the median serum values of Tartrate-resistant Acid Phosphatase 5b (TRACP-5b) (mU/dl) and serum type I collagen cross-linked N-telopeptide (NTX) (nmolBCE/l) were decreased from 535.7 and 18.5 to 230.1 and 11.9, respectively. No adverse grade 2 or higher event was observed throughout this study. Conclusion: The combined administration of minodronate and AIs was safe and effective in preventing bone loss complications in postmenopausal BC patients.