Prognostic and clinicopathological significance of platelet to lymphocyte ratio in esophageal cancer: a meta-analysis

Background: The prognostic and clinicopathological significance of the platelet to lymphocyte ratio (PLR) has been studied in various cancers. However, studies examining the role of PLR in esophageal cancer have not yielded consistent results. The purpose of this meta-analysis was to study the prognostic and clinicopathological significance of PLR in esophageal cancer patients. Methods: We performed a literature search in three major databases: PubMed, Web of Science and Embase (up until May 1, 2017). The clinicopathologic significance of PLR and its prognostic significance were analyzed. Results: Our meta-analysis consisted of 13 studies with 4,621 patients. The pooled hazard ratios (HRs) showed that a high PLR was associated with poor survival of esophageal cancer [HR = 1.283; 95% confidence interval (CI): 1.173-1.404; P<0.001]. Subgroup analysis revealed that elevated PLR was associated with poor survival in esophageal squamous cell carcinoma (HR = 1.281; 95% CI: 1.098-1.493; P= 0.002). The pooled odds ratio (OR) indicated that high PLR was also associated with the depth of tumor invasion (OR = 1.543, 95% CI: 1.269-1.876, P<0.001), lymph node metastasis (OR = 1.427, 95% CI: 1.195-1.705, P<0.001), tumor length (OR = 1.81, 95% CI: 1.331-2.461, P<0.001), and Tumor stage (OR = 1.459, 95% CI: 1.235-1.724, P<0.001). Conclusions: Our results demonstrate that elevated PLR was significantly associated with poor prognosis of esophageal cancer. Furthermore, the high PLR might predict worse clinicopathological features of esophageal cancer patients.