title: Influence of margins on overall survival after hepatic resection for colorectal metastasis: a meta-analysis.
abstract: OBJECTIVE
  The aim of our study was to conduct a meta-analysis of reports published on hepatic resection for colorectal liver metastasis (CRLM) and determine whether a negative margin of 1 cm or more confers a survival advantage over subcentimeter negative margins.
  
  
  BACKGROUND
  Surgical margin is an important prognostic factor in patients undergoing hepatic resection for CRLM. Although there is a consensus that positive margins portend a worse outcome than negative margins, the extent of negative margins remains controversial.
  
  
  METHODS
  A PubMed search was conducted to identify articles on hepatic resection for CRLM. The 357 initially located articles were screened to identify 90 articles of interest. The texts of these 90 articles were completely reviewed to finalize 18 articles for inclusion in the study on the basis of absolute and relative inclusion criteria. Patients with positive margins were excluded from the meta-analysis. Meta-analysis was performed using STATA 9.2 statistical software.
  
  
  RESULTS
  A total of 4821 patients with negative margins from the 18 studies were included in the meta-analysis. The overall 5-year survival for all patients was 41% [95% confidence interval (CI), 40%-43%]. The overall 5-year survival for the ≥1 cm negative margin subgroup was 46% (95% CI, 44%-48%) when compared with 38% (95% CI, 36%-40%) for less than 1 cm negative margin subgroup. The odds ratio for 1-cm or more negative margins was found to be 0.773 (95% CI, 0.638-0.938; P = 0.009) when compared with less than 1 cm negative margins.
  
  
  CONCLUSIONS
  The results of this meta-analysis demonstrate that in patients undergoing hepatic resection for CRLM, a negative margin of 1 cm or more confers a survival advantage when compared with subcentimeter negative margins.
authors.affiliation: Department of Surgery, Division of Surgical Oncology, Eppley Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA.
authors.forename: Mashaal
authors.initials: M
authors.lastname: Dhir
authors.forename: Elizabeth R
authors.initials: ER
authors.lastname: Lyden
authors.forename: Antai
authors.initials: A
authors.lastname: Wang
authors.forename: Lynette M
authors.initials: LM
authors.lastname: Smith
authors.forename: Fred
authors.initials: F
authors.lastname: Ullrich
authors.forename: Chandrakanth
authors.initials: C
authors.lastname: Are
mesh_terms: D015179:Colorectal Neoplasms / Q000401:mortality* / Q000473:pathology / Q000601:surgery; D018572:Disease-Free Survival; D006498:Hepatectomy / Q000379:methods*; D006801:Humans; D008099:Liver / Q000473:pathology; D008113:Liver Neoplasms / Q000401:mortality* / Q000473:pathology / Q000556:secondary* / Q000601:surgery*; D016017:Odds Ratio