Usefulness of bone markers for detection of bone metastases in lung cancer patients

Objectives: Lung cancer commonly causes destructive bone metastases. The aim of this study was to compare efficiency of biochemical bone markers in the detection of bone metastases in lung cancer patients. Design and methods: We measured serum calcium (Ca), alkaline phosphatase (ALP), bone isoenzyme of alkaline phosphatase (BALP), osteocalcin (OC) and urine deoxypyridinoline crosslinks (DPD) levels in 52 lung cancer patients; 27 patients with the evidence of bone metastases, 25 without metastases in bone when they were first diagnosed. BALP, OC and DPD were measured by specific immunoassays. ALP, Ca and urine creatinine levels were determined by colorimetric methods. Results: Ca, ALP, BALP, OC and DPD levels were significantly higher in the patients with bone metastases than those without bone metastases (p< 0.01 for BALP and OC, p< 0.001 for Ca, ALP and DPD). The sensitivity and specificities of all markers as follows: 89%–44% for BALP, 52%–88% for OC, 81%–76% for DPD, respectively. ROC curves were generated separately for BALP, OC and DPD to assess the diagnostic efficiency of markers in a different manner. DPD showed the best curve characteristics among the studied bone markers, followed by the BALP curve. OC curve showed poor characteristics. Conclusions: Our results suggest that the measurement of DPD and BALP may be useful in detecting bone metastases in lung cancer patients. Also it could help in the follow-up of bone metastases from lung cancer since they can be repeated more often than roentgenography and bone scintigraphy, at less cost and with less discomfort to the patients