The clinical importance of bone metabolic markers in detecting bone metastasis of lung cancer

The aim of this study was to evaluate the role of bone metabolic markers in clinical evaluation of bone metastasis of lung cancer. Sixty-five male patients with lung cancer were included in this trial, 77% of whom were diagnosed as having non-small cell lung cancer and 20% were small cell lung cancer. The presence of bone metastasis was investigated by whole-body bone scintigraphy via Tc-99m mostly (80%) and, in some cases, PET/CT (positron emission tomography and computerized tomography) which was performed for staging. Bone-specific alkaline phosphatase (BALP) and osteocalcin were measured in serum of the patients as markers of bone formation. N-terminal telopeptide (NTX) and beta-form of C terminal telopeptide (beta-CTX) were studied as bone destruction markers. The cases were divided into two groups according to the presence of bone metastasis. Twenty-three patients (35%) had bone metastasis. Serum levels of total ALP, BALP and NTX were significantly higher in the group with bone metastasis (p < 0.05). Osteocalcin and beta-CTX levels were not significantly different between two groups. According to ROC-curve analysis, at the threshold value of 22.38 mu g/L, the sensitivity of BALP was 60.87% and the specificity was 69.05%. Similarly, at the threshold value of 25.69 nmol BCE, the sensitivity of NTX was 90.24% and the specificity was 43.4%. Bone metabolic markers are considered noninvasive, useful and cost-effective. However, more prospective studies are needed in order to use them for evaluation of bone metastasis in lung cancer.