Biomarkers of bone turnover in oncology: applications in diagnosis and treatment.

IMPORTANCE OF THE FIELD: Metastatic bone disease results from interactions between cancer and normal bone cells. These growth factor and cytokine-mediated interactions lead to stimulation of both osteoclast and osteoblast function with uncoupling and imbalance in bone remodelling, reflected in changes in bone biomarkers. AREAS COVERED IN THIS REVIEW: To evaluate the application of bone biomarkers in the clinical management of metastatic bone disease through a detailed review of the medical literature What the reader will gain: Clinicians and laboratory scientists interested in bone markers will be introduced to a range of highly specific and easily and reliably measured bone biomarkers available for clinical use. TAKE HOME MESSAGE: Bone biomarkers provide information on the rates of bone resorption and formation. Although this information is insufficient to enable earlier diagnosis of bone metastases than is possible with imaging and clinical assessments, the rate of bone turnover, especially bone resorption, provides powerful, clinically useful, prognostic and predictive information. Patients with elevated bone marker levels are significantly more likely to experience a bone complication than those with normal levels. Also, clinical benefit from bisphosphonates appears to be related to the effective suppression of accelerated bone turnover. Bone complications are fewer and survival better in patients achieving normal rates of bone resorption. These observations provide an opportunity to personalise therapy, avoid overtreatment and improve cost-effectiveness by adjusting treatment to maintain a normal rate of bone resorption.