title: Detection of occult tumor cells in regional lymph nodes is associated with poor survival in pN0 non-small cell lung cancer: a meta-analysis.
abstract: BACKGROUND
  patients of pN0 non-small cell lung cancer (NSCLC) with occult tumor cells (OTCs) in regional lymph nodes (LNs) are reported to have controversial prognostic outcomes.
  
  
  METHODS
  We pooled pN0 NSCLC patients with OTCs in LNs and compared with those without OTCs. Patient characteristics, hazard ratios (HRs) and 95% confidence intervals (CIs) for overall survival (OS) and/or disease-free survival (DFS) were analyzed. HR greater than 1 conferred an increased hazard for patients with OTCs.
  
  
  RESULTS
  Eighteen articles were finally enrolled in the meta-analysis and 15 studies provided sufficient data for extracting HRs for OS, resulting to 5 articles available for DFS analysis. The combined HRs of OS was 2.22 (95% CI, 1.87 to 2.64) and 2.4 (95% CI, 1.71 to 3.36) for analysis of DFS. The similar trend was obtained in the subgroup analyses regarding detection methods and study type. Interestingly, even in the analysis of mean numbers of LNs dissection (MLND) intraoperatively, both subgroups (LNs/Pts. <12 and ≥12) illustrated significant HRs of OS (HR: 3.13, 95% CI, 2.17 to 4.52 in LNs/Pts. <12 subgroup and HR: 2.09, 95% CI, 1.63 to 2.68 in LNs/Pts. ≥12). The combined HR of OS in this section was 2.37 (95% CI, 1.63 to 2.68). No publication bias was detected in all the meta-analysis sections. The prognosis of patients with OTCs is inferior to those without OTCs in the terms of OS and DFS regardless of detection methods, study types and MLND.
  
  
  CONCLUSIONS
  The prognosis of patients with OTCs is inferior to those without OTCs in the terms of OS and DFS regardless of detection methods, study types and MLND.
authors.affiliation: 1 Department of Thoracic Surgery, Jiangsu Province Hospital, the First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China ; 2 Department of Epidemiology and Biostatistics, School of Public Health, Nanjing Medical University, Nanjing 210029, China.
authors.forename: Zhicheng
authors.initials: Z
authors.lastname: He
authors.affiliation: 1 Department of Thoracic Surgery, Jiangsu Province Hospital, the First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China ; 2 Department of Epidemiology and Biostatistics, School of Public Health, Nanjing Medical University, Nanjing 210029, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Xia
authors.affiliation: 1 Department of Thoracic Surgery, Jiangsu Province Hospital, the First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China ; 2 Department of Epidemiology and Biostatistics, School of Public Health, Nanjing Medical University, Nanjing 210029, China.
authors.forename: Shaowen
authors.initials: S
authors.lastname: Tang
authors.affiliation: 1 Department of Thoracic Surgery, Jiangsu Province Hospital, the First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China ; 2 Department of Epidemiology and Biostatistics, School of Public Health, Nanjing Medical University, Nanjing 210029, China.
authors.forename: Yijiang
authors.initials: Y
authors.lastname: Chen
authors.affiliation: 1 Department of Thoracic Surgery, Jiangsu Province Hospital, the First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China ; 2 Department of Epidemiology and Biostatistics, School of Public Health, Nanjing Medical University, Nanjing 210029, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Chen
keywords: Non-small cell lung cancer (NSCLC); early stage; hazard ratio (HR); meta-analysis; occult tumor cells (OTCs)