title: Study protocol: population screening for colorectal cancer by colonoscopy or CT colonography: a randomized controlled trial.
abstract: BACKGROUND
  Colorectal cancer (CRC) is the second most prevalent type of cancer in Europe. Early detection and removal of CRC or its precursor lesions by population screening can reduce mortality. Colonoscopy and computed tomography colonography (CT colonography) are highly accurate exams and screening options that examine the entire colon. The success of screening depends on the participation rate. We designed a randomized trial to compare the uptake, yield and costs of direct colonoscopy population screening, using either a telephone consultation or a consultation at the outpatient clinic, versus CT colonography first, with colonoscopy in CT colonography positives.
  
  
  METHODS
  7,500 persons between 50 and 75 years will be randomly selected from the electronic database of the municipal administration registration and will receive an invitation to participate in either CT colonography (2,500 persons) or colonoscopy (5,000 persons) screening. Those invited for colonoscopy screening will be randomized to a prior consultation either by telephone or a visit at the outpatient clinic. All CT colonography invitees will have a prior consultation by telephone. Invitees are instructed to consult their general practitioner and not to participate in screening if they have symptoms suggestive for CRC. After providing informed consent, participants will be scheduled for the screening procedure. The primary outcome measure of this study is the participation rate. Secondary outcomes are the diagnostic yield, the expected and perceived burden of the screening test, level of informed choice and cost-effectiveness of both screening methods.
  
  
  CONCLUSIONS
  This study will provide further evidence to enable decision making in population screening for colorectal cancer.
  
  
  BACKGROUND
  Dutch trial register: NTR1829.
authors.affiliation: Department of Gastroenterology and Hepatology, Academic Medical Centre, Amsterdam, the Netherlands.
authors.forename: Thomas R
authors.initials: TR
authors.lastname: de Wijkerslooth
authors.forename: Margriet C
authors.initials: MC
authors.lastname: de Haan
authors.forename: Esther M
authors.initials: EM
authors.lastname: Stoop
authors.forename: Marije
authors.initials: M
authors.lastname: Deutekom
authors.forename: Paul
authors.initials: P
authors.lastname: Fockens
authors.forename: Patrick M M
authors.initials: PM
authors.lastname: Bossuyt
authors.forename: Maarten
authors.initials: M
authors.lastname: Thomeer
authors.forename: Marjolein
authors.initials: M
authors.lastname: van Ballegooijen
authors.forename: Marie-Louise
authors.initials: ML
authors.lastname: Essink-Bot
authors.forename: Monique E
authors.initials: ME
authors.lastname: van Leerdam
authors.forename: Ernst J
authors.initials: EJ
authors.lastname: Kuipers
authors.forename: Evelien
authors.initials: E
authors.lastname: Dekker
authors.forename: Jaap
authors.initials: J
authors.lastname: Stoker
mesh_terms: D000368:Aged; D023881:Colonography, Computed Tomographic / Q000009:adverse effects / Q000191:economics / Q000706:statistics & numerical data; D003113:Colonoscopy / Q000009:adverse effects / Q000191:economics / Q000706:statistics & numerical data; D015179:Colorectal Neoplasms / Q000175:diagnosis*; D003256:Community Participation; D003362:Cost-Benefit Analysis; D006801:Humans; D008403:Mass Screening / Q000379:methods*; D008875:Middle Aged; D009426:Netherlands; D012017:Referral and Consultation; D012307:Risk Factors