Prognostic value of platelet-to-lymphocyte ratio in oncologic outcomes of esophageal cancer: A systematic review and meta-analysis

The platelet-to-lymphocyte ratio (PLR) is a useful prognostic factor in several cancers. However, the prognostic role of PLR in esophageal cancer remains controversial. The aim of this study is to evaluate the association between PLR and the oncologic outcome of esophageal cancer patients through a meta-analysis. Relevant articles were researched from Embase, PubMed, and Web of Science databases. The meta-analysis was performed using hazard ratio (HR) and 95% confidence intervals (CIs) as effect measures. Finally, 19 articles with 6134 patients were included in our study. The summary results indicated that the elevated PLR was negatively related to overall survival (HR= 1.263; 95% CI 1.094, 1.458). The subgroup analysis revealed that increased PLR was associated with poor overall survival in esophageal cancer patients for Asians (HR=1.252; 95% CI 1.141, 1.373) but not for Caucasians (HR=1.463; 95% CI 0.611, 3.502). When the patients were segregated by pathological type, sample size, and HR estimate method, high PLR was also significantly correlated with poor overall survival. In contrast, elevated PLR was not statistically associated with disease-free survival or cancer-specific survival. High PLR is associated with poor overall survival in patients with esophageal cancer. PLR may be a significant predictive biomarker in patients with esophageal cancer. Further large-cohort studies are needed to confirm these findings.