Clinicopathological and prognostic significance of lymphocyte to monocyte ratio in patients with gastric cancer: A meta-analysis

Background: Recently, the lymphocyte-to-monocyte ratio (LMR) has been reported to be a prognostic factor in multiple malignancies. The current study was designed to assess the prognostic value of pretreatment LMR in gastric cancer (GC). Methods: MEDLINE, EMBASE, Cochrane, and CNKI databases were searched until April 2017. Eligible articles were defined as studies assessing the prognostic role of pretreatment LMR in GC. Pooled hazard ratios (HRs) for overall survival (OS), disease-free survival (DFS), and recurrence-free survival (RFS) were calculated using fixed-effects or random-effects models. Results: A total of six studies comprising 4908 patients were included in the study. Pooled results showed that low LMR was significantly associated with decreased OS (HR: 0.66, 95% confidence interval [CI]: 0.54-0.82, p < .001), but not with poor DFS/RFS (HR: 0.71, 95% CI: 0.38-1.32, p = .004). The unfavorable prognostic impact of low LMR on OS was observed in patients of different disease stages and cut-off values. Moreover, low LMR was significantly related to age (> median), gender (male), CEA (> 5 ng/ml), tumor size (> 3 cm), TNM stage (III-IV), lymph node metastasis, and distant metastasis. Conclusions: Low pretreatment LMR may be a significant prognostic biomarker for poor OS in patients with GC.