title: Prognostic value of lymph node ratio in patients with pathological N1 non-small cell lung cancer: a systematic review with meta-analysis.
abstract: BACKGROUND
  Non-small cell lung cancer (NSCLC) patients with N1 disease have variable outcomes, and additional prognostic factors are needed. The number of positive lymph nodes (LNs) has been proposed as a prognostic indicator. However, the number of positive LNs depends on the number of LNs examined from the resection specimen. The lymph node ratio (LNR) can circumvent this limitation. The purpose of this study is to evaluate LNR as a predictor of survival and recurrence in patients with pathologic N1 NSCLC.
  
  
  METHODS
  We systematically reviewed studies published before March 17, 2016, on the prognostic value of LNR in patients with pathologic N1 NSCLC. The hazard ratios (HRs) and their 95% confidence intervals (CIs) were used to combine the data. We also evaluated heterogeneity and publication bias.
  
  
  RESULTS
  Five studies published between 2010 and 2014 were eligible for this systematic review with meta-analysis. The total number of patients included was 6,130 ranging from 75 to 4,004 patients per study. The combined HR for all eligible studies evaluating the overall survival (OS) and disease-free survival (DFS) of N1 LNR in patients with pathologic N1 NSCLC was 1.53 (95% CI: 1.22-1.85) and 1.64 (95% CI: 1.19-2.09), respectively. We found no heterogeneity and publication bias between the reports.
  
  
  CONCLUSIONS
  LNR is a worthy predictor of survival and cancer recurrence in patients with pathological N1 NSCLC.
authors.affiliation: 1 Department of Respiratory and Critical Care Medicine, Jinling Hospital, School of Medicine, Nanjing University, Nanjing 210002, China ; 2 Division of Cardiothoracic Surgery, Washington University in St. Louis, St. Louis, USA ; 3 Division of Thoracic Oncology, European Institute of Oncology, Milan, Italy ; 4 Department of Thoracic Surgery, St. James's University Hospital in Leeds, UK ; 5 School of Public Health, University of Memphis, Memphis, TN, USA ; 6 Thoracic Oncology Research Group, Baptist Cancer Center, Memphis, TN, USA.
authors.forename: Qian
authors.initials: Q
authors.lastname: Li
authors.affiliation: 1 Department of Respiratory and Critical Care Medicine, Jinling Hospital, School of Medicine, Nanjing University, Nanjing 210002, China ; 2 Division of Cardiothoracic Surgery, Washington University in St. Louis, St. Louis, USA ; 3 Division of Thoracic Oncology, European Institute of Oncology, Milan, Italy ; 4 Department of Thoracic Surgery, St. James's University Hospital in Leeds, UK ; 5 School of Public Health, University of Memphis, Memphis, TN, USA ; 6 Thoracic Oncology Research Group, Baptist Cancer Center, Memphis, TN, USA.
authors.forename: Ping
authors.initials: P
authors.lastname: Zhan
authors.affiliation: 1 Department of Respiratory and Critical Care Medicine, Jinling Hospital, School of Medicine, Nanjing University, Nanjing 210002, China ; 2 Division of Cardiothoracic Surgery, Washington University in St. Louis, St. Louis, USA ; 3 Division of Thoracic Oncology, European Institute of Oncology, Milan, Italy ; 4 Department of Thoracic Surgery, St. James's University Hospital in Leeds, UK ; 5 School of Public Health, University of Memphis, Memphis, TN, USA ; 6 Thoracic Oncology Research Group, Baptist Cancer Center, Memphis, TN, USA.
authors.forename: Dongmei
authors.initials: D
authors.lastname: Yuan
authors.affiliation: 1 Department of Respiratory and Critical Care Medicine, Jinling Hospital, School of Medicine, Nanjing University, Nanjing 210002, China ; 2 Division of Cardiothoracic Surgery, Washington University in St. Louis, St. Louis, USA ; 3 Division of Thoracic Oncology, European Institute of Oncology, Milan, Italy ; 4 Department of Thoracic Surgery, St. James's University Hospital in Leeds, UK ; 5 School of Public Health, University of Memphis, Memphis, TN, USA ; 6 Thoracic Oncology Research Group, Baptist Cancer Center, Memphis, TN, USA.
authors.forename: Tangfeng
authors.initials: T
authors.lastname: Lv
authors.affiliation: 1 Department of Respiratory and Critical Care Medicine, Jinling Hospital, School of Medicine, Nanjing University, Nanjing 210002, China ; 2 Division of Cardiothoracic Surgery, Washington University in St. Louis, St. Louis, USA ; 3 Division of Thoracic Oncology, European Institute of Oncology, Milan, Italy ; 4 Department of Thoracic Surgery, St. James's University Hospital in Leeds, UK ; 5 School of Public Health, University of Memphis, Memphis, TN, USA ; 6 Thoracic Oncology Research Group, Baptist Cancer Center, Memphis, TN, USA.
authors.forename: Alexander Sasha
authors.initials: AS
authors.lastname: Krupnick
authors.affiliation: 1 Department of Respiratory and Critical Care Medicine, Jinling Hospital, School of Medicine, Nanjing University, Nanjing 210002, China ; 2 Division of Cardiothoracic Surgery, Washington University in St. Louis, St. Louis, USA ; 3 Division of Thoracic Oncology, European Institute of Oncology, Milan, Italy ; 4 Department of Thoracic Surgery, St. James's University Hospital in Leeds, UK ; 5 School of Public Health, University of Memphis, Memphis, TN, USA ; 6 Thoracic Oncology Research Group, Baptist Cancer Center, Memphis, TN, USA.
authors.forename: Antonio
authors.initials: A
authors.lastname: Passaro
authors.affiliation: 1 Department of Respiratory and Critical Care Medicine, Jinling Hospital, School of Medicine, Nanjing University, Nanjing 210002, China ; 2 Division of Cardiothoracic Surgery, Washington University in St. Louis, St. Louis, USA ; 3 Division of Thoracic Oncology, European Institute of Oncology, Milan, Italy ; 4 Department of Thoracic Surgery, St. James's University Hospital in Leeds, UK ; 5 School of Public Health, University of Memphis, Memphis, TN, USA ; 6 Thoracic Oncology Research Group, Baptist Cancer Center, Memphis, TN, USA.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Brunelli
authors.affiliation: 1 Department of Respiratory and Critical Care Medicine, Jinling Hospital, School of Medicine, Nanjing University, Nanjing 210002, China ; 2 Division of Cardiothoracic Surgery, Washington University in St. Louis, St. Louis, USA ; 3 Division of Thoracic Oncology, European Institute of Oncology, Milan, Italy ; 4 Department of Thoracic Surgery, St. James's University Hospital in Leeds, UK ; 5 School of Public Health, University of Memphis, Memphis, TN, USA ; 6 Thoracic Oncology Research Group, Baptist Cancer Center, Memphis, TN, USA.
authors.forename: Matthew P
authors.initials: MP
authors.lastname: Smeltzer
authors.affiliation: 1 Department of Respiratory and Critical Care Medicine, Jinling Hospital, School of Medicine, Nanjing University, Nanjing 210002, China ; 2 Division of Cardiothoracic Surgery, Washington University in St. Louis, St. Louis, USA ; 3 Division of Thoracic Oncology, European Institute of Oncology, Milan, Italy ; 4 Department of Thoracic Surgery, St. James's University Hospital in Leeds, UK ; 5 School of Public Health, University of Memphis, Memphis, TN, USA ; 6 Thoracic Oncology Research Group, Baptist Cancer Center, Memphis, TN, USA.
authors.forename: Raymond U
authors.initials: RU
authors.lastname: Osarogiagbon
authors.affiliation: 1 Department of Respiratory and Critical Care Medicine, Jinling Hospital, School of Medicine, Nanjing University, Nanjing 210002, China ; 2 Division of Cardiothoracic Surgery, Washington University in St. Louis, St. Louis, USA ; 3 Division of Thoracic Oncology, European Institute of Oncology, Milan, Italy ; 4 Department of Thoracic Surgery, St. James's University Hospital in Leeds, UK ; 5 School of Public Health, University of Memphis, Memphis, TN, USA ; 6 Thoracic Oncology Research Group, Baptist Cancer Center, Memphis, TN, USA.
authors.forename: Yong
authors.initials: Y
authors.lastname: Song
keywords: Lymph node ratio (LNR); N1 node, meta-analysis; non-small cell lung cancer (NSCLC)