title: Surgeon and hospital characteristics as predictors of major adverse outcomes following colon cancer surgery: understanding the volume-outcome relationship.
abstract: OBJECTIVE
  Although numerous studies have demonstrated an association between surgical volume and improved outcome in cancer surgery, the specific structures and mechanisms of care that are associated with volume and lead to improved outcomes remain poorly defined. We hypothesize that there are modifiable surgeon and hospital characteristics that explain observed volume-outcome relationships.
  
  
  METHODS
  Retrospective cohort study.
  
  
  METHODS
  Surveillance, Epidemiology, and End Results cancer registry areas.
  
  
  METHODS
  Patients aged 66 years and older, diagnosed and surgically treated for stage I, II, or III colon cancer between 1992 and 1996 (n = 22 672).
  
  
  METHODS
  Thirty-day postoperative mortality and 30-day postoperative procedural interventions, including reoperation and image-guided percutaneous procedures.
  
  
  RESULTS
  Surgeon volume, but not hospital volume, is a significant predictor of postoperative procedural intervention (adjusted odds ratio for very high-volume surgeons vs low-volume surgeons, 0.79; 95% confidence interval, 0.64-0.98). In the unadjusted analyses, high hospital volume (odds ratio, 0.67; 95% confidence interval, 0.56-0.81) and very high hospital volume (odds ratio, 0.65; 95% confidence interval, 0.54-0.79) is associated with lower postoperative mortality. Postoperative procedural intervention is not a significant mediator of the relationship between hospital volume and mortality. A single variable-the presence of sophisticated clinical services-was the most important explanatory variable underlying the relationship between hospital volume and mortality.
  
  
  CONCLUSIONS
  Very high surgeon volume is associated with a reduction in surgical complications. However, the association between increasing hospital volume and postoperative mortality appears to derive mainly from a full spectrum of clinical services that may facilitate the prompt recognition and treatment of complications.
authors.affiliation: Department of Surgery, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA. billingk@ohsu.edu
authors.forename: Kevin G
authors.initials: KG
authors.lastname: Billingsley
authors.forename: Arden M
authors.initials: AM
authors.lastname: Morris
authors.forename: Jason A
authors.initials: JA
authors.lastname: Dominitz
authors.forename: Barbara
authors.initials: B
authors.lastname: Matthews
authors.forename: Sharon
authors.initials: S
authors.lastname: Dobie
authors.forename: William
authors.initials: W
authors.lastname: Barlow
authors.forename: George E
authors.initials: GE
authors.lastname: Wright
authors.forename: Laura-Mae
authors.initials: LM
authors.lastname: Baldwin
mesh_terms: D000230:Adenocarcinoma / Q000601:surgery*; D000368:Aged; D002983:Clinical Competence; D003110:Colonic Neoplasms / Q000401:mortality / Q000601:surgery*; D013505:Digestive System Surgical Procedures / Q000401:mortality / Q000592:standards / Q000706:statistics & numerical data*; D005260:Female; D013502:General Surgery / Q000706:statistics & numerical data; D006761:Hospitals / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D017063:Outcome Assessment, Health Care; D011183:Postoperative Complications / Q000453:epidemiology; D012086:Reoperation / Q000706:statistics & numerical data; D012189:Retrospective Studies; D012959:Socioeconomic Factors; D016019:Survival Analysis