Bone-directed therapy and breast cancer: Bisphosphonates, monoclonal antibodies, and radionuclides

Abstract

Breast cancer bone metastasis causes severe morbidity and is commonly encountered in daily clinical practice. It causes pain, pathologic fractures, spinal cord and other nerve compression syndromes and life-threatening hypercalcemia. Breast cancer metastasizes to the bone through a complicated process that involves numerous molecules. Metastatic cells disrupt normal bone turnover and create a vicious cycle. All treatment effort is directed to breaking this vicious cycle. Bisphosphonates have been used safely for more than two decades. As a group, bisphosphonates delay the time to the first skeletal-related event and reduce pain. However, they do not prevent the development of bone metastasis in patients with no bone metastasis and do not prolong survival. The receptor activator for nuclear factor κB ligand inhibitor denosumab also delays the time to the first skeletal-related event and reduces the skeletal morbidity rate. Radionuclides are another treatment option for bone pain.