title: Effect of hospital volume on postoperative mortality and survival after oesophageal and gastric cancer surgery in the Netherlands between 1989 and 2009.
abstract: BACKGROUND
  High hospital volume is associated with better outcomes after oesophagectomy and gastrectomy. In the Netherlands, a minimal volume standard of 10 oesophagectomies per year was introduced in 2006. For gastrectomy, no minimal volume standard was set. Aims of this study were to describe changes in hospital volumes, mortality and survival and to explore if high hospital volume is associated with better outcomes after oesophagectomy and gastrectomy in the Netherlands.
  
  
  METHODS
  From 1989 to 2009, 24,246 patients underwent oesophagectomy (N = 10,025) or gastrectomy (N = 14,221) in the Netherlands. Annual hospital volumes were defined as very low (1-5), low (6-10), medium (11-20), and high (≥ 21). Volume-outcome analyses were performed using Cox regression, adjusting for year of diagnosis, case-mix and the use of multi-modality treatment.
  
  
  RESULTS
  From 1989 to 2009, the percentage of patients treated in high-volume hospitals increased for oesophagectomy (from 7% to 64%), but decreased for gastrectomy (from 8% to 5%). Six-month mortality (from 15% to 7%) and 3-year survival (from 41% to 52%) improved after oesophagectomy, and to a lesser extent after gastrectomy (6-month mortality: 15%-10%, three-year survival: 55-58%). High hospital volume was associated with lower 6-month mortality (hazard ratio (HR) 0.48, P<0.001) and longer 3-year survival (HR 0.77, P<0.001) after oesophagectomy, but not after gastrectomy.
  
  
  CONCLUSIONS
  Oesophagectomy was effectively centralised in the Netherlands, improving mortality and survival. Gastrectomies were mainly performed in low volumes, and outcomes after gastrectomy improved to a lesser extent, indicating an urgent need for improvement in quality of surgery and perioperative care for gastric cancer in the Netherlands.
authors.affiliation: Department of Surgery, Leiden University Medical Center, Albinusdreef 2, 2333ZA Leiden, The Netherlands.
authors.forename: Johan L
authors.initials: JL
authors.lastname: Dikken
authors.forename: Anneriet E
authors.initials: AE
authors.lastname: Dassen
authors.forename: Valery E P
authors.initials: VE
authors.lastname: Lemmens
authors.forename: Hein
authors.initials: H
authors.lastname: Putter
authors.forename: Pieta
authors.initials: P
authors.lastname: Krijnen
authors.forename: Lydia
authors.initials: L
authors.lastname: van der Geest
authors.forename: Koop
authors.initials: K
authors.lastname: Bosscha
authors.forename: Marcel
authors.initials: M
authors.lastname: Verheij
authors.forename: Cornelis J H
authors.initials: CJ
authors.lastname: van de Velde
authors.forename: Michel W J M
authors.initials: MW
authors.lastname: Wouters
mesh_terms: D000368:Aged; D004938:Esophageal Neoplasms / Q000401:mortality* / Q000473:pathology / Q000601:surgery*; D016629:Esophagectomy / Q000401:mortality / Q000706:statistics & numerical data; D005260:Female; D005743:Gastrectomy / Q000401:mortality / Q000706:statistics & numerical data; D006761:Hospitals / Q000706:statistics & numerical data*; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009426:Netherlands; D013274:Stomach Neoplasms / Q000401:mortality* / Q000473:pathology / Q000601:surgery*