A systemic review and meta-analysis for prognostic values of pretreatment lymphocyte-to-monocyte ratio on gastric cancer

Abstract

The systemic inflammation plays a crucial role in carcinogenesis and cancer progression. Pretreatment lymphocyte-to-monocyte ratio (LMR) has been suggested to be associated with clinical outcomes in various malignancies. To evaluate the prognostic significance of pretreatment LMR on gastric cancer, we conducted a comprehensive literature search in PubMed, Embase, Web of Science, Cochrane Library, and ClinicalTrials.gov (Prospero Registration No. CRD42018087263). This meta-analysis included all studies evaluating the prognostic significance of pretreatment LMR on gastric cancer. The main outcome measures included overall survival (OS), progression-free survival (PFS), and the relationship between LMR and clinicopathological features. In total, 11 studies (12 cohorts) enrolling 14,262 patients with gastric cancer were included. The pooled estimates showed that elevated pretreatment LMR was significantly associated with better OS (hazard ratio (HR): 0.71, 95% confidence interval (CI): 0.58–0.83) and better PFS (HR: 0.71, 95% CI: 0.44–0.99). The elevated LMR was also significantly associated with young patients, female, low level of carcinoembryonic antigen (CEA), low level of carbohydrate antigen 19-9 (CA19-9), stage I–II, small tumor size, absence of lymph node metastasis, absence of vascular invasion, and absence of perineural invasion. In conclusion, the elevated pretreatment LMR predicted the better clinical outcomes in patients with gastric cancer.