Prognostic value of the C‐reactive protein to albumin ratio in esophageal cancer: A systematic review and meta‐analysis

In recent years, some studies suggested that the pretreatment C-reactive protein to albumin ratio (CAR) may be predictive for prognosis of esophageal cancer (EC), but their results were inconsistent. Therefore, the current meta-analysis was preformed to better determine the prognostic value of pretreatment CAR in EC. The PubMed, EMBASE, Web of Science, Cochrane Library, and PubMed Central databases were searched up to January 10, 2019 to identify studies evaluating the correlation between CAR and prognosis of EC. The primary outcome was the overall survival (OS) and secondary outcomes were disease-free survival (DFS) and cancer-specific survival (CSS). Pooled hazard ratios (HRs) and corresponding 95% confidence intervals (95% CIs) were used to estimate the predictive role of CAR for prognosis in EC. Based on the results of this research, a total of 11 studies with 2930 patients diagnosed as EC were included. Pooled results suggested that elevated pretreatment CAR was significantly associated with poor OS (HR = 1.80, 95% CI: 1.31-2.47, P < .001) with high heterogeneity (I(2) = 86.5%, P < .001) and poor CSS (HR = 1.72, 95% CI: 1.33-2.22, P < .001) without heterogeneity (I(2) = 0.0%, P < .323); however, no significant association was observed between pretreatment CAR and DFS (HR = 1.41, 95% CI: 0.60-3.34, P = .429) with high heterogeneity (I(2) = 76.7%, P < .038). Subgroup analyses further manifested that EC patients with higher CAR had worse OS. An elevated pretreatment CAR may indicate poor survival in patients with EC. Thus, pretreatment CAR may serve as a promising biomarker in EC and could be used to predict prognosis and help decision-making in clinical work.