Clinical value of N-MID and β-CTx for the diagnosis of bone metastases

Objective: Assessment of bone turnover is becoming a test of potent in metastatic bone disorders recently. This study attempted to evaluate the clinical value of bone metabolism markers N-terminal midfragment of osteocalcin (N-MID) and β-carboxy-terminal telopeptide of type I collagen (β-CTx) for the diagnosis of bone metastases. Methods: Eighty-four cancer patients were divided into two groups: with (n=17, grade 1; n=12, grade 2; n=16, grade 3; n=13: grade 4) and without (n=26, grade 0) bone metastases according to bone imaging. Serum N-MID, β-CTx, 25-hydroxy-vitamin D (25-OH-D), calcitonin (CT) and serum calcium (Ca) levels were measured. Results: The median of β-CTx (0.42 μg/L) in patients with bone metastases was significantly higher than those without(O.27 μg/L, Z=-0.784, P<0.05). The levels of N-MID, 25-OH-D, CT and serum Ca showed no significant differences between the two groups. The more advanced grade, the higher level of β-CTx. All differences were significant except those between grades 0 and 1,1 and 2 (F0,1=1.602, F1,2=3.890, all P>0.05). The level of N-MID increased with more advanced grades, however, the differences were not significant. So were 25-OH-D, CT and serum Ca. Conclusion: β-CTx might be useful for diagnosing bone metastases but further research is needed. (authors)