Bisphosphonates in breast cancer.

Breast cancer is the leading type of cancer among women, and bone metastases are common in patients with breast cancer, affecting more than half of all patients with advanced disease. Bisphosphonates are the current standard of care for preventing skeletal complications associated with bone metastases. Clinical trials investigating the benefit of bisphosphonate therapy have used a composite end point defined as a skeletal-related event (SRE) or bone event, which typically includes pathologic fracture, spinal cord compression, radiation or surgery to bone, and hypercalcaemia of malignancy. Bisphosphonates significantly reduced the incidence of these events. Zoledronic acid, pamidronate, clodronate and ibandronate have demonstrated efficacy compared with placebo. Zoledronic acid has also been compared with another active bisphosphonate (i.e. pamidronate) and shown by multiple event analysis to be significantly more effective at reducing the risk of SREs. Bisphosphonates effectively reduce and prevent skeletal complications in patients with bone metastases from breast cancer. Preclinical data suggest that bisphosphonates have antitumour effects. Bisphosphonates may also be of use in the adjuvant setting.