The combination of preoperative serum C-reactive protein and carcinoembryonic antigen is a useful prognostic factor in patients with esophageal squamous cell carcinoma: a combined ROC analysis

Background: The prognostic value of inflammatory index in esophageal cancer (EC) has not been established. In the present study, therefore, we initially evaluated a novel prognostic system, named the COCC (COmbination of C-reactive protein [CRP] and carcinoembryonic antigen [CEA]), for making a prognosis in patients with esophageal squamous cell carcinoma (ESCC). Methods: A total of 327 patients with ESCC between January 2006 and December 2008 were included in this retrospective study. The COCC was calculated by combined CRP and CEA according to the logistic equation. The Kaplan-Meier method was used to calculate the cancer-specific survival (CSS), and the difference was assessed by the log-rank test. Cox regression analyses were performed to evaluate the prognostic factors. Results: In our study, COCC was defined as CRP + 0.71 CEA according to the logistic equation. Receiver operating characteristic curves for CSS prediction were plotted to verify the optimum cutoff points for CRP, CEA, and COCC, which were 9.8 mg/L, 4.2 ng/mL, and 8.0, respectively. Patients with COCC. 8.0 had a significantly better CSS than patients with COCC. 8.0 (53.1% vs 15.3%, P. 0.001). Multivariate analysis revealed that COCC was an independent prognostic factor in patients with ESCC (P= 0.006). In addition, the area under the curve (AUC) was 0.722 for COCC, 0.645 for CRP, and 0.618 for CEA, indicating that COCC was superior to CRP or CEA for CSS prediction. Conclusion: The COCC is an independent prognostic factor in patients with ESCC. We conclude that COCC was superior to CRP or CEA as a more precise prognostic factor in patients with ESCC.