BIOCHEMICAL MARKERS OF BONE TURNOVER IN PATIENTS WITH METASTATIC BONE-DISEASE

Several biochemical markers of bone formation and bone resorption have recently been developed, These markers have been evaluated for clinic al utility in patients with metabolic bone disease, including Paget di sease and osteoporosis, and for their potential use in cancer patients whose disease has metastasized to bone. We have evaluated seven marke rs of bone turnover in the plasma and urine of 94 patients with newly diagnosed or progressive malignancy with and without clinical evidence of bone metastases. As determined by a positive bone scan and (or) bo ne survey, 30 patients had metastases to bone; 51 patients had metasta tic cancer without overt bony involvement; and 13 patients had local d isease without bone metastases. To evaluate the predictive value of th ese markers in the metastatic population, we utilized a ''Z-score'' an d logistic regression analysis to distinguish patients with documented bone metastatic disease from those patients without clinical evidence of bone metastases. The higher the Z-score, the better the marker pre dicts the presence of bone metastases. With this statistical approach, urine N-telopeptide measurements had the highest Z-score and the most significant association with the probability of bone metastases. Urin e deoxypyridinoline was the second most predictive marker of bone meta stases. Thus, biochemical markers of bone resorption might be of use t o predict the presence of bone metastases in cancer patients and to mo nitor the efficacy of antiresorptive therapy in patients treated for m etastatic bone disease.