The clinical significance of serum markers of bone turnover in NSCLC patients: surveillance, management and prognostic implications.

The purpose of this study was to investigate various serum markers of bone turnover in non-small cell lung cancer patients (NSCLC) in the presence or absence of bone metastasis. Our retrospective study included 79 newly diagnosed NSCLC patients. Group A included 51 patients with bone metastasis and group B included 28 patients that never developed bone metastasis. The measurement of bone formation markers, bone resorptive markers and osteoclastogenesis markers as well as routine biochemical analysis was determined. Patients with bone metastasis had an increase in receptor activator of nuclear factor kappaB ligand, osteopontin and osteoprotegerin. Patients who later developed bone metastasis had decreased osteocalcin and tartrate-resistant acid phosphatase isoform 5b levels (TRACP-5b). We also found an unusually low TRACP-5b/RANKL ratio for patients who have or later developed metastasis. In patients that never developed bone metastases, cross-linked carboxy-terminal telopeptide of type I collagen was increased. Positive correlations were found between osteopontin and TRACP-5b, and also between bone alkaline phosphatase with osteocalcin and TRACP-5b. In conclusion, serum markers of bone turnover may be able to determine the time-to-tumor progression, metastatic potential and overall survival of the NSCLC patient. In addition, they may contribute to a more accurate follow-up and tailored treatment options.