title: Random comparison of repeated faecal immunochemical testing at different intervals for population-based colorectal cancer screening.
abstract: OBJECTIVE
  Colorectal cancer screening by means of faecal immunochemical tests (FITs) requires successive screening rounds for an optimal preventive effect. However, data on the influence of the length of the screening interval on participation and diagnostic yield are lacking. Repeated FIT screening was therefore performed in a population-based trial comparing various repeat intervals.
  
  
  METHODS
  7501 Dutch individuals aged 50-74 years were randomly selected and invited for two 1-sample FIT screening rounds (haemoglobin (Hb) concentration ≥ 50 ng/ml, corresponding to 10 μg Hb/g faeces) with intervals of 1 (group I), 2 (group II) or 3 years (group III).
  
  
  RESULTS
  In group I, participation was 64.7% in the first screening round and 63.2% in the second. The corresponding percentages for groups II and III were 61.0% vs 62.5% and 62.0% vs 64.0%. Triennial screening resulted in a higher participation rate in the second screening round compared with annual screening (p=0.04). The overall positivity rate in the second screening round was significantly lower compared with the first round (6.0% vs 8.4%; OR 0.69, 95% CI 0.58 to 0.82) and did not depend on interval length (p=0.23). Similarly, the overall detection rate of advanced neoplasia was significantly lower in the second round compared with the first screening round (1.9% vs 3.3%; OR 0.57, 95% CI 0.43 to 0.76) and also did not depend on interval length (p=0.62). The positive predictive value of the FIT did not significantly change over time (41% vs 33%; p=0.07).
  
  
  CONCLUSIONS
  The total number of advanced neoplasia found at repeat FIT screening is not influenced by the interval length within a range of 1-3 years. Furthermore, there is a stable and acceptably high participation in the second screening round. This implies that screening intervals can be tailored to local resources.
authors.affiliation: Erasmus University Medical Centre, Department of Gastroenterology and Hepatology, 's Gravendijkwal 230, 3015 CE Rotterdam, The Netherlands. a.vanroon@erasmusmc.nl
authors.forename: Aafke H C
authors.initials: AH
authors.lastname: van Roon
authors.forename: S Luuk
authors.initials: SL
authors.lastname: Goede
authors.forename: Marjolein
authors.initials: M
authors.lastname: van Ballegooijen
authors.forename: Anneke J
authors.initials: AJ
authors.lastname: van Vuuren
authors.forename: Caspar W N
authors.initials: CW
authors.lastname: Looman
authors.forename: Katharina
authors.initials: K
authors.lastname: Biermann
authors.forename: Jacqueline C I Y
authors.initials: JC
authors.lastname: Reijerink
authors.forename: Hans 't
authors.initials: H'
authors.lastname: Mannetje
authors.forename: Alexandra C M
authors.initials: AC
authors.lastname: van der Togt
authors.forename: J Dik F
authors.initials: JD
authors.lastname: Habbema
authors.forename: Monique E
authors.initials: ME
authors.lastname: van Leerdam
authors.forename: Ernst J
authors.initials: EJ
authors.lastname: Kuipers
mesh_terms: D000236:Adenoma / Q000175:diagnosis*; D000368:Aged; D015179:Colorectal Neoplasms / Q000175:diagnosis*; D055088:Early Detection of Cancer / Q000379:methods; D005243:Feces / Q000737:chemistry*; D005500:Follow-Up Studies; D006454:Hemoglobins / Q000032:analysis*; D006801:Humans; D007120:Immunochemistry; D008403:Mass Screening; D008875:Middle Aged; D009780:Occult Blood; D012680:Sensitivity and Specificity; D013997:Time Factors
chemical_list: D006454:Hemoglobins