The role of bisphosphonates in breast cancer.

Patients with bone metastases from breast cancer are at high risk for debilitating skeletal complications. Bisphosphonates are effective inhibitors of tumour-induced bone resorption and significantly reduce the risk of skeletal complications in these patients. Several bisphosphonates have been investigated for the treatment of bone metastases in patients with breast cancer, including clodronate, pamidronate, ibandronate, and zoledronic acid. Among these agents, intravenous pamidronate and zoledronic acid have demonstrated the greatest clinical benefit based on conservative endpoints. Zoledronic acid is the only agent to be compared with another active bisphosphonate and has been shown to significantly reduce the risk of skeletal complications compared with pamidronate. On the basis of these results, zoledronic acid has rapidly become the new international standard of care for patients with bone metastases from breast cancer.