Cytokeratin 19-fragments (CYFRA 21-1) as a novel serum biomarker for response and survival in patients with advanced pancreatic cancer

Background: CYFRA 21-1 serves as biomarker in several epithelial malignancies. However, its role in pancreatic cancer (PC) has not yet been investigated. Methods: Within a prospective single-centre study serial blood samples were collected from patients with confirmed advanced PC. Pre-treatment values and weekly measurements of CYFRA 21-1, carbohydrate antigen 19-9 (CA 19-9) and carcinoembryonic antigen (assessed by Elecsys 2010, Roche Diagnostics) during palliative first-line chemotherapy were obtained. Biomarker data were correlated with objective response (determined by RECIST) as well as time to progression (TTP) and overall survival (OS) using uni- and multivariate analyses. Results: Seventy-eight patients were included, 45% of these received treatment in prospective clinical trials. Median TTP was 3.9 months, median OS 7.7 months. Pre-treatment CYFRA 21-1 levels were significantly associated with performance status (P=0.0399) and stage of disease (P=0.0001). Marker values before chemotherapy and at the 2-month staging of all three markers were considered significant predictors for objective treatment response. Pre-treatment CYFRA 21-1 levels, as well as CA 19-9 values, could be applied to define subgroups (categorised by tertiles) with a different OS outcome (CYFRA: 14.8 vs 7.1 vs 4.8 months, CA 19-9: 14.2 vs 7.1 vs 5.2 months; P<0.0001). CYFRA 21-1 and CA 19-9 (both as categorised and as continuous variables) showed a highly significant correlation with TTP and OS at nearly all-time points assessed in univariate analysis. In multivariate analysis, only CYFRA 21-1 and performance status were independent predictors for OS. Conclusions: CYFRA 21-1 may serve as a valuable tool for monitoring treatment response and assessing prognosis in advanced PC.