Pyridinoline cross-linked carboxyterminal telopeptide of type I collagen as a useful marker for monitoring metastatic bone activity in men with prostate cancer

Purpose: We investigated the clinical usefulness of measuring the serum concentrations of pyridinoline cross-linked carboxyterminal telopeptide of type I collagen (ICTP) and carboxyterminal propeptide of type I procollagen (PICP) as markers for monitoring metastatic bone activity in patients with prostate cancer. Materials and Methods: Serum levels of ICTP, PICP, alkaline phosphatase, prostatic acid phosphatase and prostate specific antigen (PSA) were analyzed in 104 untreated patients with prostate cancer, including 62 with and 42 without bone metastasis. Serial measurements of ICTP, PICP and PSA were performed during hormonal therapy in 35 of 62 prostate cancer patients with bone metastasis. Results: Serum levels of all markers except prostatic acid phosphatase were significantly higher with than without bone metastasis. The median values of each marker increased according to the extent of bone metastasis. Serial ICTP, PICP and PSA in 19 patients with a partial response or no change in bone scans demonstrated a downward trend after treatment, while in 16 with progression they showed an upward trend after treatment. The rate of detecting bone metastasis and progression using ICTP were highest compared with other markers based on the percent clinical effectiveness and receiver operating characteristic curves. Conclusions: Measuring serum ICTP may be useful for detecting bone metastasis and prostate cancer progression, and may augment PSA and bone scan monitoring of metastatic bone activity.