SIMULTANEOUS ASSESSMENT OF BONE-COLLAGEN SYNTHESIS AND DEGRADATION INPATIENTS WITH DIFFERENT MALIGNANT-TUMORS - COMPARISON WITH THE RESULTS OF TC-99M-METHYLENE BISPHOSPHONATE BONE-SCINTIGRAPHY

We report on the diagnostic validity of the serum concentrations of th e C-terminal propeptide of type I procollagen (a marker of bone format ion) and of the urinary excretion of deoxypyridinoline (a marker of bo ne resorption) in a consecutive series of 89 tumour patients who were routinely examined by Tc-99m-methylene bisphosphonate bone scintigraph y for detection of bone metastases. Z score analysis reveals that the discriminating power of deoxypyridinoline is superior to that of calci um excretion whereas the discriminating power of the C-terminal propep tide concentrations is inferior to that of bone alkaline phosphatase v alues. Accuracy (as assessed by the area under the receiver-operating characteristic curve) was 0.75 for deoxypyridinoline and 0.82 for the C-terminal propeptide. Combination of both markers did not yield an in crease of accuracy (0.82) compared with the determination of the C-ter minal propeptide concentrations alone. There was a correlation (r = 0.398; p < 0.0001) between C-terminal propeptide concentrations and de oxypyridinoline excretion values in the group of 89 patients examined. Further studies should be done to elucidate whether the determination of bone collagen turnover is suitable as a screening procedure for de tecting bone metastases.