Diagnostic Usefulness and Changing Value during Irradiation of Bone Metabolic Markers for Metastatic Bone Tumor

Objective: We examined the efficacy of Pyridinoline-cross-linked C-terminal telopeptide of type I collagen (ICTP) and C-terminal propep tide of the type I procollagen (PICP), as bone metabolic markers (BMM) that reflect the effects of radiotherapy in patients with metastatic bone tumors (MBT). Method: One-hundred eight patients who had had malignant tumors and been suspected of developing MBT were measured for ICTP and PICP. Ninety six patients with recognized MBT and 12 patients without MBT were evaluated for the diagnostic accuracy of MBT. Out of the 96 cases, 49 received radiotherapy and were measured for ICTP and PICP before and after the treatment. The 49 cases were divided into 25 cases (Com group) that had all of the MBT irradiated and 24 cases (InCom group) that could not have all sites irradiated. Increase ratios from before to after the radiotherapy were compared between ICTP and PICP. Results: In the 96 patients with MBT, both ICTP and PICP were observed to be significantly high. Diagnostic accuracy was 81.5% for ICTP, and 61.6% for PICP. InCom group showed an increase in ICTP by about 25% while no significant change was observed in the Com group. Conclusion: BMM has diagnostic significance in patients with MBT. Performing radiotherapy to every osseous lesion results in a decline or leveling-off of ICTP.