Clinical Usefulness of Serum Carboxyterminal Propeptide of Type I Procollagen and Pyridinoline Cross-linked Carboxyterminal Telopeptide of Type I Collagen in Patients with Prostate Cancer

A study was undertaken to evaluate the clinical usefulness of measurements of serum concentrations of the carboxyterminal propeptide of type I procollagen (PICP) and the pyridinoline cross-linked carboxyterminal telopeptide of type I collagen (ICTP) as parameters of bone metastasis in patients with prostate cancer. Serum PICP, ICTP, prostate-specific antigen (PSA), and alkaline phosphatase (ALP) were evaluated in 82 patients with prostate cancer and 26 patients with benign prostatic hyperplasia (BPH). These markers were measured serially in 16 prostate cancer patients during treatment. The serum levels of PICP, ICTP, ALP, and PSA were significantly higher in prostate cancer patients with bone metastasis than in patients with either BPH or prostate cancer without bone metastasis. Although the rate of detection of bone metastasis with PICP and ICTP was slightly lower than that with PSA determined by the receiver operating characteristic curve, the correlation between both PICP and ICTP and the extent of disease was much higher than that of PSA. PICP and ICTP levels varied with ALP and PSA levels, the patient's clinical course after the start of endocrine therapy and the progression of bone metastasis. The levels of PICP and ICTP did not change substantially in patients who developed local regrowth or lymph node metastasis, and decreased as bone metastases responded to radiotherapy. PICP and ICTP thus reflect the metastatic burden in bone and are useful for monitoring the response of bone metastasis to therapy.