title: Volume and outcome in colorectal cancer surgery.
abstract: OBJECTIVE
  There is a growing consensus to concentrate high-risk surgical procedures to high volume surgeons in high volume hospitals. However, there is fierce debate about centralizing more common malignancies such as colorectal cancer. The objective of this review is to conduct a meta-analysis using the best evidence available on the volume-outcome relationship for colorectal cancer treatment.
  
  
  METHODS
  A systematic search was performed to identify all relevant articles studying the relation between hospital and/or surgeon volume and clinical outcomes for colorectal cancer. Using strict inclusion criteria, 23 articles were selected concerning colon cancer, rectal cancer or both diseases together as 'colorectal cancer'. Pooled estimated effect sizes were calculated using the casemix adjusted outcomes of the highest volume group opposed to the lowest volume group.
  
  
  RESULTS
  High volume hospitals have a significantly lower postoperative mortality in half of the pooled results. Non significant results show a trend in favour of high volume hospitals. All results showed a significantly better long term survival in high volume hospitals. High volume surgeons have a lower postoperative mortality, although evidence is sparse. All analyses showed a significantly better long term survival in favour of high volume surgeons.
  
  
  CONCLUSIONS
  The results show a clear and consistent relation between high volume providers and improved long term survival. This applies to both high volume hospitals and high volume surgeons. Most results show a relation between high volume providers and a reduced postoperative mortality, but evidence is less convincing. In the ideal world, extensive population based audit registrations with casemix adjusted feedback should make rigid minimal volume standards obsolete. Until then, using volume criteria for hospitals and surgeons treating colorectal cancer can improve mortality and especially long term survival.
authors.affiliation: Department of Surgery, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: W
authors.initials: W
authors.lastname: van Gijn
authors.forename: G A
authors.initials: GA
authors.lastname: Gooiker
authors.forename: M W J M
authors.initials: MW
authors.lastname: Wouters
authors.forename: P N
authors.initials: PN
authors.lastname: Post
authors.forename: R A E M
authors.initials: RA
authors.lastname: Tollenaar
authors.forename: C J H
authors.initials: CJ
authors.lastname: van de Velde
mesh_terms: D003110:Colonic Neoplasms / Q000401:mortality / Q000601:surgery; D015179:Colorectal Neoplasms / Q000401:mortality / Q000601:surgery*; D013505:Digestive System Surgical Procedures / Q000706:statistics & numerical data*; D006761:Hospitals / Q000706:statistics & numerical data*; D006801:Humans; D009426:Netherlands / Q000453:epidemiology; D010820:Physicians / Q000706:statistics & numerical data; D012004:Rectal Neoplasms / Q000401:mortality / Q000601:surgery; D016896:Treatment Outcome