Prognostic role of lymphocyte to monocyte ratio for patients with pancreatic cancer: a systematic review and meta-analysis

BACKGROUND Lymphocyte to monocyte ratio (LMR) was recently reported as a prognostic factor of pancreatic cancer (PC). However, the prognostic role of LMR in PC remains inconsistent and inconclusive. The aim of this study was to assess the prognostic value of LMR in patients with PC through meta-analysis. METHODS Eligible studies inquiring into the connection between LMR and survival of patients with PC were collected and extracted by searching PubMed, Embase, Cochrane Library and Web of Science up to May 9, 2017. Pooled hazard ratios (HRs) and the 95% CIs were calculated to assess the prognostic value of LMR on overall survival (OS) and disease-free survival/recurrence-free survival/time to progression (DFS/RFS/TTP). RESULTS A total of 1,795 patients with PC from 8 studies were included in the meta-analysis. Pooled analysis indicated that elevated LMR predicted a favorable OS (HR =0.56, 95% CI: 0.38-0.83, P=0.004) and DFS/RFS/TTP in PC patients (HR =0.38, 95% CI: 0.15-0.95, P=0.04). Prognostic values of LMR on OS were observed in subgroups with all ethnicities, treatment with surgery, American Joint Committee on Cancer (AJCC) stage of III-IV, and LMR cut-off value ≥3. In addition, low LMR was significantly connected with gender and AJCC stage. CONCLUSION An elevated LMR is associated with favorable survival in patients with pancreatic cancer.