Prognostic value of serum cytokeratin 19 fragments in esophageal cancer: a systematic review and meta-analysis

Background: Growing number of evidence has shown that cytokeratin 19 fragment (cyfra21–1), one of the vital tumor biomarkers, was commonly utilized in diagnosing and predicting the prognosis of esophageal cancer (EC). The purpose of this systematic and meta-analysis was to quantitatively evaluate the association between cyfra21–1 and EC prognosis. Methods Relevant literature was retrieved from databases of PubMed, Web of Science, Cochrane library, and Embase. Meta-analysis was conducted using hazard ratio (HR) and 95% confidence intervals (CI) of survival outcomes as effect size to quantitatively summarize. Results Totally 2568 patients from 11 studies were included in this meta-analysis. The pooled HR showed that elevated cyfra21–1 serum level was associated with poorer overall survival (OS), with the pooled HR being 1.37 (95%CI: 1.21–1.56, P < 0.001). Subgroup analysis showed that evaluated cyfra21–1 serum level was also associated with a poorer prognosis. The pooled HR was 1.31 (95%CI: 1.14–1.51, P < 0.001) for those patients who had been treated with surgery and 1.65 (95%CI: 1.23–2.21, P < 0.001) for patients treated with non-surgery. Conclusion This meta-analysis elucidated that cyfra21–1 was a robust prognostic biomarker in EC patients. A high serum level of cyfra21–1 was associated with poorer OS in EC, indicating that cyfra21–1 may involve in the mechanism of tumor progression.