COMPARISON OF MARKERS OF BONE-FORMATION AND RESORPTION IN PROSTATE-CANCER PATIENTS TO PREDICT BONE METASTASIS

We investigated the usefulness of two biochemical markers of bone form ation (PICP, the carboxy-terminal propeptide of type I procollagen, an d bone ALP, bone-derived alkaline phosphatase) and a marker of bone re sorption (ICTP, the carboxy-terminal telopeptide of type I collagen), to determine whether the presence of bone metastasis in prostate cance r could be evaluated and the extent of bone metastasis could be strati fied by the serum levels of these markers, compared to total alkaline phosphatase (T-ALP) and prostate-specific antigen(PSA). The serum leve ls of PICP, bone ALP, ICTP, TALP and PSA were significantly higher in patients with both prostate cancer and bone metastasis (n=49) than in patients with benign prostatic hyperplasia (n=35) and patients with pr ostate cancer without bone metastasis (n=70). The superiority of a mar ker in the rate of detection of bone metastasis was evaluated with rec eiver operating characteristic curves. The serum marker levels were co mpared as a function of metastatic burden in bone (i.e., the extent of disease, EOD grade). We found that bone ALP is the most suitable mark er for evaluating bone metastasis, especially for stratifying the degr ee of bone metastasis. Both PICP and ICTP were useful in this respect, but rather inferior to bone ALP. T-ALP had the lowest ability for det ecting bone metastasis, but its correlation with the EOD grade was exc ellent, second to that of bone ALP. PSA showed limited reliability for stratifying the extent of bone metastasis.