title: Systematic review and meta-analysis of standard and extended lymphadenectomy in pancreaticoduodenectomy for pancreatic cancer.
abstract: BACKGROUND
  Although some retrospective studies of extended radical lymphadenectomy for pancreatic cancer have suggested a survival advantage, this is controversial.
  
  
  METHODS
  A literature search identified randomized controlled trials comparing extended with standard lymphadenectomy in pancreatic cancer surgery. Overall survival was analysed using hazard ratios and standard errors. Pooled estimates of overall treatment effects were calculated using a random effects model (odds ratio and 95 per cent confidence interval).
  
  
  RESULTS
  Of four randomized trials identified for systematic review, three were included in a meta-analysis of survival. The log hazard ratios (standard errors) for survival for the three trials were 0.36 (0.22), - 0.15 (0.17) and - 0.21 (0.15); the weighted mean log hazard ratio for survival overall was 0.93 (95 per cent confidence interval 0.77 to 1.13), revealing no significant differences between the standard and extended procedure (P = 0.480). Morbidity and mortality rates were also comparable, with a trend towards higher rates of delayed gastric emptying for extended lymphadenectomy. The number of resected lymph nodes was significantly higher in the extended lymphadenectomy groups (P < 0.001).
  
  
  CONCLUSIONS
  The extended procedure does not benefit overall survival, and there may even be a trend towards increased morbidity. Therefore extended lymphadenectomy should be performed only within adequately powered controlled trials, if at all.
authors.affiliation: Department of General Surgery, University of Heidelberg, Heidelberg, Germany.
authors.forename: C W
authors.initials: CW
authors.lastname: Michalski
authors.forename: J
authors.initials: J
authors.lastname: Kleeff
authors.forename: M N
authors.initials: MN
authors.lastname: Wente
authors.forename: M K
authors.initials: MK
authors.lastname: Diener
authors.forename: M W
authors.initials: MW
authors.lastname: Büchler
authors.forename: H
authors.initials: H
authors.lastname: Friess
mesh_terms: D006801:Humans; D008197:Lymph Node Excision / Q000379:methods*; D008207:Lymphatic Metastasis / Q000517:prevention & control; D010190:Pancreatic Neoplasms / Q000401:mortality / Q000601:surgery*; D016577:Pancreaticoduodenectomy / Q000379:methods* / Q000401:mortality; D016032:Randomized Controlled Trials as Topic; D015996:Survival Rate; D016896:Treatment Outcome