Serum N-telopeptide of type I collagen and bone alkaline phosphatase and their relationship in patients with non-small cell lung carcinoma and bone metastases. Preliminary results.

Lung cancer represents the most common malignancy in Western countries and the presence of bone metastasis (BMs) may significantly worsen the prognosis. Several urinary and serum markers are altered in patients with BMs from non-small cell lung cancer (NSCLC). The aim of this study was to assess the usefulness of two serum markers of bone remodeling in patients with NSCLC and BMs. Thirty-five patients (24 men, 11 women, median age 63 years, range 51-72 years) with NSCLC were examined. There were 16 patients with confirmed BMs (Group A), and 19 age-matched (63.5±4.9 vs. 63.7±4.4 years; p=0.88) patients without BMs (Group B). Serum levels of bone resorption marker cross-linked amino-terminal telopeptide of type I collegen (NTx), and bone formation marker bone alkaline phosphatase (BAP) were measured in both groups by enzyme-linked immunosorbent assay. Both NTx (33.5±7.2 vs. 25.6±3.1 nM bone collagen equivalent, BCE/l) and BAP (51.7±6.0 vs. 40.7±7.3 U/l) serum levels were significantly (p<0.001) different between groups (A vs. B). Using a cut-off value of 30 nM BCE/l (TNx) and 50 U/l (BAP), the sensitivity was 56.2% and 37.5%, respectively (Odds ratio, OR=0.47, 95% confidence interval, CI 0.11-1.91, p=0.48), while the specificity was 89.5% and 84.2% (OR=0.62, 95% CI 0.09-4.26, p=0.50), respectively. No correlation was found between age and both NTx (R=-0.34, p=0.08) and BAP (R=-0.10, p=0.61) among patients with BMs. In conclusion, in patients with NSCLC and BMs both NTx and BAP are specific markers of bone remodeling, but their usefulness is limited in early diagnosis of metastatic disease.