title: Resection of colorectal liver metastases and extra-hepatic disease: a systematic review and proportional meta-analysis of survival outcomes.
abstract: BACKGROUND
  Colorectal cancer (CRC) accounts for 9.7% of all cancers with 1.4 million new cases diagnosed each year. 19-31% of CRC patients develop colorectal liver metastases (CRLM), and 23-38% develop extra-hepatic disease (EHD). The aim of this systematic review was to determine overall survival (OS) in patients resected for CRLM and known EHD.
  
  
  METHODS
  A systematic review was undertaken to identify studies reporting OS after resection for CRLM in the presence of EHD. Proportional meta-analyses and relative risk of death before five years were assessed between patient groups.
  
  
  RESULTS
  A total of 15,144 patients with CRLM (2308 with EHD) from 52 studies were included. Three and 5-year OS were 58% and 26% for lung, 37% and 17% for peritoneum, and 35% and 15% for lymph nodes, respectively. The combined relative risk of death by five years was 1.49 (95% CI = 1.34-1.66) for lung, 1.59 (95% CI = 1.16-2.17) for peritoneal and 1.70 (95% CI = 1.57-1.84) for lymph node EHD, in favour of resection in the absence of EHD.
  
  
  CONCLUSIONS
  This review supports attempts at R0 resection in selected patients and rejects the notion that EHD is an absolute contraindication to resection.
authors.affiliation: Northern Clinical School, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: William J
authors.initials: WJ
authors.lastname: Hadden
authors.affiliation: Upper GI Surgical Unit, Royal North Shore Hospital and North Shore Private Hospital, Sydney, New South Wales, Australia.
authors.forename: Philip R
authors.initials: PR
authors.lastname: de Reuver
authors.affiliation: Northern Clinical School, University of Sydney, Sydney, New South Wales, Australia; Upper GI Surgical Unit, Royal North Shore Hospital and North Shore Private Hospital, Sydney, New South Wales, Australia.
authors.forename: Kai
authors.initials: K
authors.lastname: Brown
authors.affiliation: Northern Clinical School, University of Sydney, Sydney, New South Wales, Australia; Upper GI Surgical Unit, Royal North Shore Hospital and North Shore Private Hospital, Sydney, New South Wales, Australia.
authors.forename: Anubhav
authors.initials: A
authors.lastname: Mittal
authors.affiliation: Northern Clinical School, University of Sydney, Sydney, New South Wales, Australia; Upper GI Surgical Unit, Royal North Shore Hospital and North Shore Private Hospital, Sydney, New South Wales, Australia.
authors.forename: Jaswinder S
authors.initials: JS
authors.lastname: Samra
authors.affiliation: Northern Clinical School, University of Sydney, Sydney, New South Wales, Australia; Upper GI Surgical Unit, Royal North Shore Hospital and North Shore Private Hospital, Sydney, New South Wales, Australia. Electronic address: tom.hugh@sydney.edu.au.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Hugh
mesh_terms: D016009:Chi-Square Distribution; D015179:Colorectal Neoplasms / Q000401:mortality / Q000473:pathology*; D006498:Hepatectomy / Q000009:adverse effects / Q000401:mortality; D006801:Humans; D008113:Liver Neoplasms / Q000401:mortality / Q000556:secondary* / Q000601:surgery*; D008175:Lung Neoplasms / Q000401:mortality / Q000556:secondary / Q000601:surgery; D008207:Lymphatic Metastasis; D016017:Odds Ratio; D010534:Peritoneal Neoplasms / Q000401:mortality / Q000556:secondary / Q000601:surgery; D012307:Risk Factors; D016019:Survival Analysis; D013997:Time Factors; D016896:Treatment Outcome