title: Surgeon volume compared to hospital volume as a predictor of outcome following primary colon cancer resection.
abstract: OBJECTIVE
  A strong association between high hospital procedure volume and survival following colon cancer resection has been demonstrated. However, the importance of surgeon case volume as a determinant of outcome has been less well studied, and it is unclear whether hospital or surgeon volume is the more powerful predictor of outcomes.
  
  
  METHODS
  A retrospective population-based cohort study utilizing the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked database identified 24,166 colon cancer patients aged 65 years and older who had surgery for a primary tumor diagnosed in 1991-1996 in a SEER area. Hospital and surgeon-specific procedure volume was ascertained based on the number of claims submitted over the 6-year study period. Outcome measures were mortality at 30 days and 2 years, overall survival, and the frequency of operations requiring an intestinal stoma. Age, sex, race, comorbid illness, cancer stage, socioeconomic status, emergent hospitalization, and the presence of obstruction/perforation were used to adjust for differences in case-mix.
  
  
  RESULTS
  After adjusting for surgeon procedure volume, high hospital procedure volume remained a strong predictor of low post-operative mortality rates (P < 0.001 for each outcome with and without adjustment for surgeon procedure volume). Surgeon-specific procedure volume was also an important predictor of surgical outcomes (P = 0.002 for 30-day mortality, P = 0.001 for 2-year mortality), although this effect was attenuated after adjusting for hospital volume (P = 0.03 for 30-day mortality, P = 0.02 for 2-year mortality). Hospital volume and surgeon volume were each an important predictor of the ostomy rate. Among high volume institutions and surgeons, individual providers with unusually high ostomy rates could be identified.
  
  
  CONCLUSIONS
  Both hospital and surgeon-specific procedure volume predict outcomes following colon cancer resection; but hospital volume may exert a stronger effect. Therefore, efforts to optimize the quality of colon cancer surgery should focus on multidisciplinary aspects of hospital care rather than solely on intraoperative technique.
authors.affiliation: Health Outcomes Research Group, Department of Epidemiology and Biostatistics, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA. schragd@mskcc.org
authors.forename: Deborah
authors.initials: D
authors.lastname: Schrag
authors.forename: Katherine S
authors.initials: KS
authors.lastname: Panageas
authors.forename: Elyn
authors.initials: E
authors.lastname: Riedel
authors.forename: Lillian
authors.initials: L
authors.lastname: Hsieh
authors.forename: Peter B
authors.initials: PB
authors.lastname: Bach
authors.forename: Jose G
authors.initials: JG
authors.lastname: Guillem
authors.forename: Colin B
authors.initials: CB
authors.lastname: Begg
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D003110:Colonic Neoplasms / Q000453:epidemiology / Q000401:mortality / Q000601:surgery*; D013505:Digestive System Surgical Procedures / Q000706:statistics & numerical data*; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D008297:Male; D017063:Outcome Assessment, Health Care; D018426:SEER Program; D013503:Surgery Department, Hospital / Q000706:statistics & numerical data*; D015996:Survival Rate; D016896:Treatment Outcome