title: Hospital and surgeon volume in relation to long-term survival after oesophagectomy: systematic review and meta-analysis.
abstract: BACKGROUND
  Centralisation of healthcare, especially for advanced cancer surgery, has been a matter of debate. Clear short-term mortality benefits have been described for oesophageal cancer surgery conducted at high-volume hospitals and by high-volume surgeons.
  
  
  OBJECTIVE
  To clarify the association between hospital volume, surgeon volume and hospital type in relation to long-term survival after oesophagectomy for cancer, by a meta-analysis.
  
  
  METHODS
  The systematic literature search included PubMed, Web of Science, Cochrane library, EMBASE and Science Citation Index, for the period 1990-2013. Eligible articles were those which reported survival (time to death) as HRs after oesophagectomy for cancer by hospital volume, surgeon volume or hospital type. Fully adjusted HRs for the longest follow-up were the main outcomes. Results were pooled by a meta-analysis, and reported as HRs and 95% CIs.
  
  
  RESULTS
  Sixteen studies from seven countries met the inclusion criteria. These studies reported hospital volume (N=13), surgeon volume (N=4) or hospital type (N=4). A survival benefit was found for high-volume hospitals (HR=0.82, 95% CI 0.75 to 0.90), and possibly also, for high-volume surgeons (HR=0.87, 95% CI 0.74 to 1.02) compared with their low-volume counterparts. No association with survival remained for hospital volume after adjustment for surgeon volume (HR=1.01, 95% CI 0.97 to 1.06; N=2), while a survival benefit was found in favour of high-volume surgeons after adjustment for hospital volume (HR=0.91, 95% CI 0.85 to 0.98; N=2).
  
  
  CONCLUSIONS
  This meta-analysis demonstrated better long-term survival (even after excluding early deaths) after oesophagectomy with high-volume surgery, and surgeon volume might be more important than hospital volume. These findings support centralisation with fewer surgeons working at large centres.
authors.affiliation: Upper Gastrointestinal Surgery, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Nele
authors.identifier: http://orcid.org/0000-0003-0137-447X
authors.initials: N
authors.lastname: Brusselaers
authors.affiliation: Upper Gastrointestinal Surgery, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Fredrik
authors.initials: F
authors.lastname: Mattsson
authors.affiliation: Upper Gastrointestinal Surgery, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden Division of Cancer Studies, King's College London, General Surgery Offices, St Thomas' Hospital, London, UK.
authors.forename: Jesper
authors.initials: J
authors.lastname: Lagergren
mesh_terms: D004938:Esophageal Neoplasms / Q000401:mortality* / Q000601:surgery*; D016629:Esophagectomy; D061847:Hospitals, High-Volume; D061846:Hospitals, Low-Volume; D006801:Humans; D015233:Models, Statistical; D012044:Regression Analysis; D015996:Survival Rate; D016896:Treatment Outcome