Preliminary results of use of serum ICTP for diagnosing bone metastasis in patients with lung cancer

Objectives: To evaluate the diagnostic efficacy of Carboxyterminal cross linked telopeptide of typeⅠcollagen(ⅠCTP) for detection of early bone metastases of lung cancer. Methods: A radioimmunoassay was employed for determination of ⅠCTP concentrations in serum using a TELOPEPTIDE ⅠCTP( 125I) Raidioimmunoassay Kit (Finland).We have evaluated 86 lung cancer patients and 30 healthy controls with follow up 6 month to two years. Results: ⅠCTP serum concentrations in patients(7.24±3.09 μg/L) with bone metastasis was higher than those in patients (4.19± 2.49 μg/L ) without bone metastasis( P 0.001) and in healthy controls (3.83±1.07 μg/L )( P 0.001).The accuracy(as assessed by the area under the receiver operating characteristic curve)was higher for ⅠCTP(0.82) than for bone scintigraphy (0.74). The correlation was higher between ⅠCTP and bone metastasis(r=0.38 P 0.005) than between bone scintigraphy and bone metastasis (r=0.25, P 0.05). The sensitivity (86%) and specificity (80%) of ⅠCTP was superior to that of bone scintigraphy (81%,72%). Conclusion: ⅠCTP could be a good indicator for early diagnosis of bone metastasis in lung cancer patient, and it could be helpful in the follow up and in monitoring for bone metastasis of lung cancer. It could detect bone metastasis earlier than bone scintigraphy. A normal result of this assay indicates a very low probability of bone metastasis, while high value ICTP indicating a high possibility of bone metastasis.