Medical Treatment of Breast Cancer Bone Metastasis: From Bisphosphonates to Targeted Drugs

Breast cancer bone metastasis causing severe morbidity is commonly encountered in daily clinical practice.It causes pain, pathologic fractures, spinal cord and other nerve compression syndromes and life threateninghypercalcemia. Breast cancer metastasizes to bone through complicated steps in which numerous molecules playroles. Metastatic cells disrupt normal bone turnover and create a vicious cycle to which treatment efforts shouldbe directed. Bisphosphonates have been used safely for more than two decades. As a group they delay time to firstskeletal related event and reduce pain, but do not prevent development of bone metastasis in patients with nobone metastasis, and also do not prolong survival. The receptor activator for nuclear factor kB ligand inhibitordenosumab delays time to first skeletal related event and reduces the skeletal morbidity rate. Radionuclides areanother treatment option for bone pain. New targeted therapies and radionuclides are still under investigation.In this review we will focus on mechanisms of bone metastasis and its medical treatment in breast cancer patients.