Lymph Node Ratio as a Prognostic Marker in Pancreatic Cancer Survival: A Systematic Review and Meta-Analysis

Introduction The lymph node ratio (LNR) is defined as the ratio of number of positive lymph nodes to the total number of lymph nodes harvested during surgery. The objective of this article is to investigate the efficacy of LNR as a prognostic indicator of survival in pancreatic cancer patients who have undergone surgery by meta-analysis. Methods A systematic database search was performed in MEDLINE, Embase, and Google Scholar for relevant studies that reported LNR in pancreatic cancer. Two authors independently screened the relevant articles for selection and to extract data. All studies published in English up to April 2020 were obtained, and a total of 17,128 node-positive patients in 14 studies were included in this meta-analysis. RevMan software 5.3 (Cochrane Collaboration, the Nordic Cochrane Centre, Copenhagen, Denmark) was used for conducting all statistical analyses. Results This meta-analysis demonstrated that LNR > 0.2 significantly correlated with worse survival (hazard ratio [HR]: 1.84; 95% CI: 1.74-1.94; p ≤ 0.00001) in node-positive pancreatic cancer patients. Conclusions Our findings have demonstrated that a higher LNR is a predictor of poor survival and that LNR serves as an independent prognostic marker for assessing survival using a cut-off of 20%.