title: Factors associated with completion of bowel cancer screening and the potential effects of simplifying the screening test algorithm.
abstract: BACKGROUND
  The primary colorectal cancer screening test in England is a guaiac faecal occult blood test (gFOBt). The NHS Bowel Cancer Screening Programme (BCSP) interprets tests on six samples on up to three test kits to determine a definitive positive or negative result. However, the test algorithm fails to achieve a definitive result for a significant number of participants because they do not comply with the programme requirements. This study identifies factors associated with failed compliance and modifications to the screening algorithm that will improve the clinical effectiveness of the screening programme.
  
  
  METHODS
  The BCSP Southern Hub data for screening episodes started in 2006-2012 were analysed for participants aged 60-69 years. The variables included age, sex, level of deprivation, gFOBt results and clinical outcome.
  
  
  RESULTS
  The data set included 1,409,335 screening episodes; 95.08% of participants had a definitively normal result on kit 1 (no positive spots). Among participants asked to complete a second or third gFOBt, 5.10% and 4.65%, respectively, failed to return a valid kit. Among participants referred for follow up, 13.80% did not comply. Older age was associated with compliance at repeat testing, but non-compliance at follow up. Increasing levels of deprivation were associated with non-compliance at repeat testing and follow up. Modelling a reduction in the threshold for immediate referral led to a small increase in completion of the screening pathway.
  
  
  CONCLUSIONS
  Reducing the number of positive spots required on the first gFOBt kit for referral for follow-up and targeted measures to improve compliance with follow-up may improve completion of the screening pathway.
authors.affiliation: School of Health and Related Research, University of Sheffield, Sheffield S1 4DA, UK.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Kearns
authors.affiliation: School of Health and Related Research, University of Sheffield, Sheffield S1 4DA, UK.
authors.forename: Sophie
authors.initials: S
authors.lastname: Whyte
authors.affiliation: NHS Bowel Cancer Screening Southern Programme Hub, Guildford, Surrey GU2 7YS, UK.
authors.forename: Helen E
authors.initials: HE
authors.lastname: Seaman
authors.affiliation: NHS Bowel Cancer Screening Southern Programme Hub, Guildford, Surrey GU2 7YS, UK.
authors.forename: Julia
authors.initials: J
authors.lastname: Snowball
authors.affiliation: NHS Bowel Cancer Screening Southern Programme Hub, Guildford, Surrey GU2 7YS, UK.|Department of Biochemical Sciences, University of Surrey, Guildford, Surrey GU2 7XH, UK.
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Halloran
authors.affiliation: NHS Bowel Cancer Screening Southern Programme Hub, Guildford, Surrey GU2 7YS, UK.
authors.forename: Piers
authors.initials: P
authors.lastname: Butler
authors.affiliation: Public Health England, Sheffield, S10 3TH, UK.
authors.forename: Julietta
authors.initials: J
authors.lastname: Patnick
authors.affiliation: Public Health England, Sheffield, S10 3TH, UK.
authors.forename: Claire
authors.initials: C
authors.lastname: Nickerson
authors.affiliation: School of Health and Related Research, University of Sheffield, Sheffield S1 4DA, UK.
authors.forename: Jim
authors.initials: J
authors.lastname: Chilcott
mesh_terms: D000367:Age Factors; D000368:Aged; D000465:Algorithms; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000175:diagnosis*; D055088:Early Detection of Cancer / Q000379:methods* / Q000706:statistics & numerical data; D004739:England; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009780:Occult Blood; D010349:Patient Compliance / Q000706:statistics & numerical data*; D012017:Referral and Consultation; D012737:Sex Factors; D012923:Social Class; D013222:State Medicine