title: Population-based screening for colorectal cancer using an immunochemical faecal occult blood test: a comparison of two invitation strategies.
abstract: BACKGROUND
  To date, there is no screening programme for colorectal cancer (CRC) in Flanders, Belgium. However, The European Code Against Cancer (2003) recommends a population-based approach for CRC screening. This study aimed to obtain information about potential participation rates for a population-based screening programme for CRC in Flanders, and to compare two invitation strategies.
  
  
  METHODS
  In 2009, a trial programme for CRC screening was set up in three Flemish areas for all average-risk people aged 50-74 years, using an immunochemical faecal occult blood test (iFOBT) with a cut-off value set at 75 ng/ml of haemoglobin. The faecal sampling set was sent at random by post (mail group) or provided by the general practitioner (GP group).
  
  
  RESULTS
  In total, 19,542 people were invited to participate. Of these, 8229 provided a faecal sample, resulting in an overall participation rate of 42.1%. Participation by mail and through the GP was 52.3% (95% CI, 51.3-53.2) and 27.7% (95% CI, 26.7-28.6), respectively. The difference of 24.6% was statistically significant (95% CI, 23.3-25.9, p<0.001). Before the reminder letter was sent and the other invitation strategy was offered, the overall participation rate was 26.5% (n=5176); 36.4% (95% CI, 35.5-37.4) for the mail group and 16.6% (95% CI, 15.8-17.3) for the GP group. The odds of participating in CRC screening was almost three times higher for people invited by mail as opposed to people invited through a GP (OR=2.96, 95% CI, 2.78-3.14, p<0.001). Women were more likely to participate in CRC screening than men (OR=1.22, 95% CI, 1.15-1.30, p<0.001). In addition, we found that inhabitants from residential (OR=1.98, 95% CI, 1.85-2.11) and rural (OR=2.90, 95% CI, 2.66-3.16) areas were more likely to participate than those in urban areas. Of the 8229 people who submitted a faecal sample, 435 (5.3%) had a positive iFOBT, and of those, CRC was diagnosed in 18 (5.7%) individuals. Compliance for follow-up colonoscopy was 72.9%, and did not differ between the mail (72.4%, 95% CI, 67.5-77.3) and GP groups (74.3, 95% CI, 66.2-82.5).
  
  
  CONCLUSIONS
  Inviting people for CRC screening by means of a direct-mail invitation, and including a faecal sampling set (iFOBT), results in much higher participation rates than inviting people through the GP.
authors.affiliation: Research Group Medical Sociology and Health Policy, Department of Epidemiology and Social Medicine, University of Antwerp, Campus Drie Eiken, Universiteitsplein 1, BE-2610 Antwerp, Belgium. sofie.vanroosbroeck@ua.ac.be
authors.forename: Sofie
authors.initials: S
authors.lastname: Van Roosbroeck
authors.forename: Sarah
authors.initials: S
authors.lastname: Hoeck
authors.forename: Guido
authors.initials: G
authors.lastname: Van Hal
mesh_terms: D000368:Aged; D001530:Belgium; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000517:prevention & control*; D003256:Community Participation / Q000706:statistics & numerical data*; D055088:Early Detection of Cancer / Q000379:methods / Q000706:statistics & numerical data; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007120:Immunochemistry; D008297:Male; D008403:Mass Screening / Q000379:methods* / Q000458:organization & administration / Q000706:statistics & numerical data*; D008875:Middle Aged; D009780:Occult Blood; D016730:Program Development; D012044:Regression Analysis