Oncological validation of bone turnover markers c-terminal telopeptide of type I collagen (1CTP) and peptides n-terminal propeptide of type I procollagen (P1NP) in patients with prostate cancer and bone metastases

Background: Bone formation markers c-terminal telopeptide of type I collagen (1CTP) and peptides n-terminal propeptide of type I procollagen (P1NP) were reported to be increased in patients with prostate cancer (PC) and bone metastases. The objective of the presented study was to investigate the utility of serum 1CTP and P1NP values in the diagnosis of bone metastases and in predicting oncological outcome in patients with PC. Methods: In total, serum samples of 186 patients were included retrospectively including 53 (28.50%) benign prostatic hyperplasia (BPH) patients and 133 (71.50%) PC-patients. The group of patients with PC consisted of 58 patients with non-metastatic PC (cM0) (43.61%) and 70 (52.63%) patients with bone metastases (cM1b). Serum 1CTP and P1NP were measured by radioimmunoassay (RIA). Results were compared to clinical variables including oncologic follow-up data by univariate and multivariate analyses. Results: Median 1CTP concentrations were significantly higher in patients with PC compared to the BPH group [5.08 (range, 1.73-158.00) vs. 4.00 mu g/L (2.18-34.19), P=0.019]. However, no significant difference of P1NP levels could be shown for these groups. With median values of 6.04 (1.73-158.00) and 3.91 mu g/L (2.04-34.51) for 1CTP and 48.60 (9.12-1,074.37) and 33.90 (8.72-149.30) for P1NP both markers were altered in cM1b patients compared to cM0 patients (P=0.001 each). Furthermore, cancer-specific survival (CSS) and overall survival (OS) were significantly shorter in cM1b patients with higher 1CTP concentrations (P=0.037 and P=0.019, respectively), whereas no associations of P1NP and outcomes were observed. Conclusions: The present study confirms that increased levels of 1CTP and P1NP concentrations are associated with presence of metastatic disease in the bone. Moreover, these markers are able to predict clinical course in PC patients with bone metastases. The potential use of these markers for treatment selection in advanced PC remains to be determined.