Evaluation of Bone Metastasis Using Serial Measurements of Serum N-Telopeptides of Type I Collagen in Patients with Lung Cancer: A Prospective Study

The bone resorption biomarker cross-linked N-Telopeptides of type I collagen (NTx) has been shown to aid in the diagnosis of metastatic bone disease from lung cancer (MBDLC). Patients with MBDLC are often treated with zoledronic acid (ZA). ZA reduces the levels of NTx and also lowers the risk of skeletal adverse events in patients with MBDLC. Patients with MBDLC at initial diagnosis were included in the study. NTx was measured in serum (sNTx) once a month using the OSTEOMARKTM sNTx assay. MBDLC was assessed by monthly physical examinations and bone scintigraphy every 3 months for 12 months. Twenty patients were enrolled between June and December 2010. The sNTx concentration at baseline was 19.8 ± 5.8 nmol bone collagen equivalents (nmol BCE)/l. In the 16 patients receiving ZA, the level of sNTx significantly decreased after the first month of treatment (baseline vs. 1 month of treatment: 21.3 ± 5.5 vs. 13.6 ± 2.7 nmol BCE/l; p