title: Observational methods to assess the effectiveness of screening colonoscopy in reducing right colon cancer mortality risk: SCOLAR.
abstract: OBJECTIVE
  Screening colonoscopy's effectiveness in reducing risk of death from right colon cancers remains unclear. Methodological challenges of existing observational studies addressing this issue motivated the design of 'Effectiveness of Screening for Colorectal Cancer in Average-Risk Adults (SCOLAR)'.
  
  
  METHODS
  SCOLAR is a nested case-control study based on two large integrated health systems. This affords access to a large, well-defined historical cohort linked to integrated data on cancer outcomes, patient eligibility, test indications and important confounders.
  
  
  RESULTS
  We found electronic data adequate for excluding ineligible patients (except family history), but not the detailed information needed for test indication assignment.
  
  
  CONCLUSIONS
  The lessons of SCOLAR's design and implementation may be useful for future studies seeking to evaluate the effectiveness of screening tests in community settings.
authors.affiliation: Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Goodman
authors.affiliation: Department of Population Health, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Robert H
authors.initials: RH
authors.lastname: Fletcher
authors.affiliation: Division of Cancer Control & Population Sciences, National Cancer Institute, Bethesda, MD 20892, USA.
authors.forename: V Paul
authors.initials: VP
authors.lastname: Doria-Rose
authors.affiliation: Division of Research, Kaiser Permanente, Oakland, CA, USA.
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Jensen
authors.affiliation: Department of Family Medicine & Community Health, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
authors.forename: Alexis M
authors.initials: AM
authors.lastname: Zebrowski
authors.affiliation: Department of Research & Evaluation, Kaiser Permanente, Pasadena, CA 91107, USA.
authors.forename: Tracy A
authors.initials: TA
authors.lastname: Becerra
authors.affiliation: Department of Research & Evaluation, Kaiser Permanente, Pasadena, CA 91107, USA.
authors.forename: Virginia P
authors.initials: VP
authors.lastname: Quinn
authors.affiliation: Department of Epidemiology & Biostatistics, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA.
authors.forename: Ann G
authors.initials: AG
authors.lastname: Zauber
authors.affiliation: Division of Research, Kaiser Permanente, Oakland, CA, USA.
authors.forename: Douglas A
authors.initials: DA
authors.lastname: Corley
authors.affiliation: Department of Family Medicine & Community Health, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
authors.forename: Chyke A
authors.initials: CA
authors.lastname: Doubeni
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D003113:Colonoscopy / Q000592:standards*; D015179:Colorectal Neoplasms / Q000175:diagnosis / Q000401:mortality*; D055088:Early Detection of Cancer; D005260:Female; D006801:Humans; D008297:Male; D019370:Observation / Q000379:methods*; D012306:Risk; D014481:United States / Q000453:epidemiology
keywords: cancer screening; case–control study; colorectal cancer; selection bias