Serum concentration of type I collagen metabolites as a quantitative marker of bone metastases in patients with prostate carcinoma

Bone scans, widely used for the detection of bone metastases from prostate carcinoma, can neither quantitate metastatic lesions nor detect osteolytic lesions. Serum concentrations of the carboxyterminal propeptide of Type I procollagen (PICP), the carboxyterminal pyridinoline cross-linked telopeptide of Type I collagen (ICTP), and prostate specific antigen (PSA) were measured by radioimmunoassays in 48 patients with benign prostatic hyperplasia (BPH), 25 patients with prostate carcinoma (PCA) without bone metastases, and 36 patients with PCA and bone metastases. Serum concentrations of PICP were significantly higher in patients with PCA with bone metastases than in patients with BPH or PCA without bone metastases. No significant differences were observed between patients with BPH and those with PCA without bone metastases. Serum ICTP concentrations were significantly higher in patients with PCA than in patients with BPH regardless of the presence or absence of bone metastases. Serum concentrations of PICP, ICTP, and PSA correlated significantly with Soloway's grading system for bone scans. The serum concentrations of PICP and ICTP in patients without bone metastases showed a significant downward trend in response to antiandrogen therapy. These observations suggest that the serum concentrations of PICP and ICTP are quantitative markers of bone metastases from PCA when followed serially in individual patients. Cancer 1997; 80:1760-7. © 1997 American Cancer Society.