title: Faecal occult blood testing screening for colorectal cancer and 'missed' interval cancers: are we ignoring the elephant in the room? Results of a multicentre study.
abstract: OBJECTIVE
  Biennial faecal occult blood testing (FOBT) is used to screen for colorectal cancer throughout the UK. Interval cancers are tumours that develop in patients between screening rounds who have had a negative FOBT. Through a multicentre study, we compared the demographics of patients with interval cancers, FOBT screen detected cancers and cancers that developed in patients who chose not to participate in the screening programme.
  
  
  METHODS
  Five hundred and sixteen colorectal cancers were detected in the screening age group (60-74 years) population in three UK National Health Service hospitals over 2 years. One hundred and twenty seven (25%) were interval cancers, 161 (31%) were screen detected and 228 (44%) were cancers that developed in patients who had declined FOBT. The interval cancer group had a higher incidence of right-sided cancers (38% vs 29% and 24%), a higher proportion of high tumour stages (Dukes C and D) (70% vs 53% and 33%) and a shorter time from diagnosis to death (10 months vs 13 months and 24 months) compared to patients who had declined the FOBT and the FOBT screen detected cancers. Of all the patients studied, those with right-sided interval cancers had the worst outcome.
  
  
  CONCLUSIONS
  A quarter of the colorectal cancers diagnosed in our study were interval cancers. Patients with right-sided interval cancers had the highest proportion of Dukes C and D tumours coupled with the shortest survival time after diagnosis compared with the other groups.
authors.affiliation: Queens Medical Centre, University Hospitals Nottingham NHS Trust, Nottingham, UK.|Sherwood Forest Hospitals NHS Foundation Trust, Mansfield, UK.|Royal Derby Hospitals NHS Trust, Derby, UK.
authors.forename: A T
authors.initials: AT
authors.lastname: George
authors.affiliation: Sherwood Forest Hospitals NHS Foundation Trust, Mansfield, UK.
authors.forename: S
authors.initials: S
authors.lastname: Aggarwal
authors.affiliation: Sherwood Forest Hospitals NHS Foundation Trust, Mansfield, UK.
authors.forename: S
authors.initials: S
authors.lastname: Dharmavaram
authors.affiliation: Sherwood Forest Hospitals NHS Foundation Trust, Mansfield, UK.
authors.forename: A
authors.initials: A
authors.lastname: Menon
authors.affiliation: Sherwood Forest Hospitals NHS Foundation Trust, Mansfield, UK.
authors.forename: M
authors.initials: M
authors.lastname: Dube
authors.affiliation: BCSP Eastern Hub, Queens Medical Centre, Nottingham, UK.
authors.forename: M
authors.initials: M
authors.lastname: Vogler
authors.affiliation: BCSP Eastern Hub, Queens Medical Centre, Nottingham, UK.
authors.forename: A
authors.initials: A
authors.lastname: Field
mesh_terms: D000368:Aged; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000401:mortality; D057210:Delayed Diagnosis; D055088:Early Detection of Cancer / Q000009:adverse effects* / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000009:adverse effects* / Q000379:methods; D008875:Middle Aged; D009313:National Health Programs; D009780:Occult Blood; D013997:Time Factors; D006113:United Kingdom
keywords: Bowel cancer screening; fecal occult blood testing; interval cancers; missed cancers