title: Critical review of the prognostic significance of pathological variables in patients undergoing resection for colorectal liver metastases.
abstract: OBJECTIVE
  The aim of this study was to identify prognostic factors, particularly pathological variables, that influence disease-free and overall survival following resection for colorectal liver metastases (CRLM).
  
  
  METHODS
  Patients undergoing CRLM resection from January 2005 to December 2011 were included. Data analysed included information on demographics, laboratory results, operative findings, histopathological features and survival.
  
  
  RESULTS
  A total of 259 patients were included. Of these, 138 (53.3%) patients developed recurrent disease, of which 95 died. The median length of follow-up in the remaining patients was 28 months (range: 12-96 months). There were significant associations between recurrence and higher tumour number (P = 0.002), presence of perineural invasion (P = 0.009) and positive margin (R1) resection (P = 0.002). Multivariate analysis showed all three prognostic factors to be independent predictors of disease-free survival. Significantly poorer overall survival after hepatic resection for CRLM was observed in patients undergoing hemi-hepatectomy or more radical resection (P = 0.021), patients with a higher number of tumours (P = 0.024) and patients with perineural invasion (P < 0.001). Multivariate analysis showed perineural invasion to be the only independent predictor of overall survival.
  
  
  CONCLUSIONS
  The presence of perineural invasion, multiple tumours and an R1 margin were associated with recurrent disease. Perineural invasion was also an independent prognostic factor with respect to overall survival.
authors.affiliation: Department of Hepatobiliary and Pancreatic Surgery, Queen's Medical Centre, Nottingham University Hospitals NHS Trust, Nottingham, UK.
authors.forename: Dhanwant
authors.initials: D
authors.lastname: Gomez
authors.forename: Abed M
authors.initials: AM
authors.lastname: Zaitoun
authors.forename: Antonella
authors.initials: A
authors.lastname: De Rosa
authors.forename: Sina
authors.initials: S
authors.lastname: Hossaini
authors.forename: Ian J
authors.initials: IJ
authors.lastname: Beckingham
authors.forename: Adam
authors.initials: A
authors.lastname: Brooks
authors.forename: Iain C
authors.initials: IC
authors.lastname: Cameron
mesh_terms: D000368:Aged; D016009:Chi-Square Distribution; D015179:Colorectal Neoplasms / Q000401:mortality / Q000473:pathology*; D018572:Disease-Free Survival; D005260:Female; D006498:Hepatectomy / Q000009:adverse effects / Q000401:mortality; D006801:Humans; D053208:Kaplan-Meier Estimate; D008113:Liver Neoplasms / Q000401:mortality / Q000556:secondary* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local; D018365:Neoplasm, Residual; D010525:Peripheral Nerves / Q000473:pathology; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome