Prevention of bone metastases from breast cancer by adjuvant bisphosphonate therapy.

There is increasing evidence regarding the importance of osteoclast activation in the pathogenesis of bone metastases. Cancer cells produce osteoclast-activating factors which play an important role in the development of bone metastases. Bisphosphonates are drugs that inhibit bone turnover by decreasing bone resorption. In patients with bone metastases from breast cancer, the effectiveness of bisphosphonate is well established for reducing skeletal complications, such as bone pain, pathological fracture, bone surgery and hypercalcemia. Recent attention has focused on a possible preventive effect on bisphosphonates of bone metastases. Animal models have supported the prevention of bone metastasis by bishosphonate therapy, but three major adjuvant clinical trials of the oral bisphosphonate clodronate have yielded conflicting results. However, our preliminary trial of intravenous bisphosphonate with pamidronate showed effective inhibition of bone metastases. Use of bisphosphonates as adjuvant therapy is still investigational yet promising. Several more randomized trials are underway to further investigate adjuvant therapy with bisphosphonates.