Efficacy of a single 5 mg zoledronic acid infusion in preventing bone loss and fracture in postmenopausal women with breast cancer.

INTRODUCTION

Chemotherapy-induced bone loss (CTIBL) is common among breast cancer patients, requiring comprehensive assessment and intervention. Zoledronic acid, a strong inhibitor of bone resorption, is effective in CTIBL management, though information on dosing and intervals, particularly the efficacy of the 5 mg annual dose for osteoporosis in breast cancer patients, is limited.

MATERIALS AND METHODS

In this 12-month prospective observational study, 85 breast cancer patients were divided into three groups: 17 received no treatment, 17 received tamoxifen, and 51 received anastrozole or letrozole (AI). Post-surgery, patients were administered a single 5 mg dose of zoledronic acid and monitored over 12 months for changes in bone mineral density (BMD), fracture rates, and biochemical markers.

RESULTS

Initially, the AI group was the oldest, averaging 59.1 ± 8.7 years. At baseline, no significant differences in variables, except age, were observed. After 12 months, BMD increased in all groups following a single zoledronic acid dose, with the smallest increase in the AI group at the lumbar spine: no treatment (2.4% ± 6.1%), tamoxifen (2.6% ± 3.4%), AI (0.6% ± 14.5%) (p = 0.778). CTx and P1NP levels were consistently suppressed up to 12 months post-treatment, with smaller reductions in the AI group. There were no significant differences in fracture or bone metastasis rates among groups.

CONCLUSION

A single infusion of 5 mg zoledronic acid was effective in increasing bone density in breast cancer patients. However, AI-treated patients showed less improvement in vertebral bone mineral density and biochemical markers. Further long-term studies with larger cohorts are needed.