Prognostic value of peripheral blood lymphocyte-to-monocyte ratio in patients with solid tumors: a meta-analysis

BACKGROUND: Although accumulating evidence suggests peripheral blood lymphocyte-to-monocyte ratio (LMR) could act as a prognosis predictor in various tumors, the prognostic value of LMR still remains controversial. We carried out this meta-analysis to evaluate the association of pretreatment LMR with survival outcomes in patients with solid tumors. METHODS: Eligible studies were collected and extracted by searching PubMed and Embase databases up to June 3, 2015. The pooled hazard ratios (HRs) and their 95% confidence intervals (CIs) were computed to assess the prognostic value of LMR quantitatively. RESULTS: Eighteen studies with a total of 8,377 participants were enrolled in this meta-analysis. Our findings indicated that elevated pre-treatment LMR predicted a significantly favorable overall survival (HR=0.59, 95% CI: 0.53–0.67) and disease-free survival (HR=0.74, 95% CI: 0.68–0.80) in solid tumor patients. Subgroup analyses revealed that enhanced LMR was significantly associated with favorable overall survival in patients with digestive system cancers (HR=0.63, 95% CI: 0.49–0.81), urinary tract tumors (HR=0.66, 95% CI: 0.52–0.84), lung cancer (HR=0.62, 95% CI: 0.54–0.72), and nasopharyngeal carcinoma (HR=0.50, 95% CI: 0.43–0.57). CONCLUSION: This meta-analysis showed that enhanced LMR may indicate a favorable prognosis in patients with solid tumors.