Novel approaches to the management of bone metastases

Standard management of breast cancer metastatic to bone includes systemic chemotherapy and, if applicable, hormone therapy, as well as radiotherapy for control of pain or prevention of pathologic fractures. In addition, orthopedic surgical procedures are used to prevent or correct pathologic fractures in weight-bearing areas of the osseous skeleton. Inhibitors of osteoclast function, including bisphosphonates and gallium nitrate, have been shown in clinical trials to decrease bone-related complications. Consequently, bisphosphonates have become an integral part of the management of bone metastases from breast cancer. Improved understanding of the biology of osteoclastogenesis led to the identification of osteoprotegerin as a critical modulator of osteoclast activity. The clinical evaluation of several osteoprotegerin preparations has shown therapeutic effects as measured by significant reductions in biochemical markers of bone resorption. Monoclonal antibodies to RANK ligand and parathyroid hormone-related protein, as well as Src kinase inhibitors, are also currently under clinical evaluation.