title: Preferences for colorectal cancer screening strategies: a discrete choice experiment.
abstract: BACKGROUND
  Guidelines underline the role of individual preferences in the selection of a screening test, as insufficient evidence is available to recommend one screening test over another. We conducted a study to determine the preferences of individuals and to predict uptake for colorectal cancer (CRC) screening programmes using various screening tests.
  
  
  METHODS
  A discrete choice experiment (DCE) questionnaire was distributed among naive subjects, yet to be screened, and previously screened subjects, aged 50-75 years. Subjects were asked to choose between scenarios on the basis of faecal occult blood test (FOBT), flexible sigmoidoscopy (FS), total colonoscopy (TC) with various test-specific screening intervals and mortality reductions, and no screening (opt-out).
  
  
  RESULTS
  In total, 489 out of 1498 (33%) screening-naïve subjects (52% male; mean age+/-s.d. 61+/-7 years) and 545 out of 769 (71%) previously screened subjects (52% male; mean age+/-s.d. 61+/-6 years) returned the questionnaire. The type of screening test, screening interval, and risk reduction of CRC-related mortality influenced subjects' preferences (all P<0.05). Screening-naive and previously screened subjects equally preferred 5-yearly FS and 10-yearly TC (P=0.24; P=0.11), but favoured both strategies to annual FOBT screening (all P-values <0.001) if, based on the literature, realistic risk reduction of CRC-related mortality was applied. Screening-naive and previously screened subjects were willing to undergo a 10-yearly TC instead of a 5-yearly FS to obtain an additional risk reduction of CRC-related mortality of 45% (P<0.001).
  
  
  CONCLUSIONS
  These data provide insight into the extent by which interval and risk reduction of CRC-related mortality affect preferences for CRC screening tests. Assuming realistic test characteristics, subjects in the target population preferred endoscopic screening over FOBT screening, partly, due to the more favourable risk reduction of CRC-related mortality by endoscopy screening. Increasing the knowledge of potential screenees regarding risk reduction by different screening strategies is, therefore, warranted to prevent unrealistic expectations and to optimise informed choice.
authors.affiliation: Departments of Gastroenterology and Hepatology, Erasmus MC, University Medical Centre, 's-Gravendijkwal 230, Rotterdam, The Netherlands. l.hol.1@erasmusmc.nl
authors.forename: L
authors.initials: L
authors.lastname: Hol
authors.forename: E W
authors.initials: EW
authors.lastname: de Bekker-Grob
authors.forename: L
authors.initials: L
authors.lastname: van Dam
authors.forename: B
authors.initials: B
authors.lastname: Donkers
authors.forename: E J
authors.initials: EJ
authors.lastname: Kuipers
authors.forename: J D F
authors.initials: JD
authors.lastname: Habbema
authors.forename: E W
authors.initials: EW
authors.lastname: Steyerberg
authors.forename: M E
authors.initials: ME
authors.lastname: van Leerdam
authors.forename: M L
authors.initials: ML
authors.lastname: Essink-Bot
mesh_terms: D000368:Aged; D000465:Algorithms; D001294:Attitude to Health; D002277:Carcinoma / Q000175:diagnosis* / Q000401:mortality; D002755:Choice Behavior / Q000502:physiology; D003113:Colonoscopy / Q000523:psychology / Q000706:statistics & numerical data; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000401:mortality; D055088:Early Detection of Cancer / Q000379:methods* / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009780:Occult Blood; D057240:Patient Preference / Q000706:statistics & numerical data*; D040242:Risk Reduction Behavior; D012812:Sigmoidoscopy / Q000523:psychology / Q000706:statistics & numerical data; D011795:Surveys and Questionnaires; D016019:Survival Analysis