Usefulness of bone metabolic markers in the diagnosis of bone metastasis from lung cancer

Abstract

Bone metastasis is common in lung cancer patient and the diagnosis of bone metastasis is usually made by using imaging techniques, especially bone scintigraphy. However, the diagnostic yield from bone scintigraphy is limited. The aim of this study is to assess the clinical usefulness of urinary pyridinoline cross-linked N-telopeptides of Type I collagen (NTx), urinary deoxypyridinoline (DPD), and serum alkaline phosphatase (ALP) in the assessment of bone metastasis in patients with lung cancer. Urinary NTx, DPD, and serum ALP were measured in 151 lung cancer patients (33 with and 118 without bone metastasis). Lung cancer patients with bone metastasis had a higher urinary excretion of NTx and DPD, and a higher serum ALP than those without bone metastasis. NTx had a better receiver operating characteristic (ROC) curve than DPD and ALP, since the areas under the ROC curve were 0.82, 0.79, and 0.71, respectively. Although correlation coefficients among NTx, DPD and ALP were significantly positive (p < 0.005), the strongest relationship was appeared between NTx and DPD (R = 0.616). In conclusion, our results showed the utility of the new bone markers in detecting bone metastasis and suggested that measurement of urinary NTx was valid diagnostic method of bone metastasis from lung cancer.

Fig. 1

Urinary concentrations of (A) pyridinoline cross-linked N-telopeptides of Type I collagen (NTx), (B) deoxypyridinoline (DPD) and (C) serum alkaline phosphatase (ALP) in lung cancer patients with and without bone metastasis. The horizontal bar represents the mean value and the upper reference limit for these assay is shown by the broken line.

Fig. 2

Receiver operating characteristic curves of urinary pyridinoline cross-linked N-telopeptides of Type I collagen (NTx, -■-), deoxypyridinoline (DPD, -○-), and serum alkaline phosphatase (ALP,-▼-) in the diagnosis of bone metastasis. The areas under the receiver operating characteristic curves for NTx, DPD, and ALP were 0.82, 0.79, and 0.71, respectively.

Fig. 3

(A) Correlation of urinary pyridinoline cross-linked N-telopeptides of Type I collagen (NTx) and serum alkaline phosphatase (ALP) levels in lung cancer patients (correlation coefficient [R]=0.588; p=0.001). (B) Correlation of urinary deoxypyridinoline (DPD) and serum ALP levels in lung cancer patients (R=0.503; p=0.001) (C) Correlation of urinary NTx and DPD levels in lung cancer patients (R=0.616; p=0.001).