Gut 61:1050-1057 doi:10.1136/gutjnl-2011-300651
  • Colon
  • Original article

Colonoscopy quality measures: experience from the NHS Bowel Cancer Screening Programme

  1. Colin J Rees3,4,10
  1. 1University Hospital of North Tees, Stockton-on-Tees, UK
  2. 2Institute of Health and Society, Newcastle University, Newcastle upon Tyne, UK
  3. 3Northern Region Endoscopy Group (NREG) South Tyneside District Hospital, Harton Lane, South Shields, Tyne and Wear, UK
  4. 4Durham University, Queen's Campus, University Boulevard, Stockton-on-Tees, UK
  5. 5Cancer Epidemiology Unit, Oxford, UK
  6. 6Cancer Screening Evaluation Unit, Institute of Cancer Research, University of London, Sutton, London, UK
  7. 7Derbyshire Bowel Cancer Screening Centre, Derby City General Hospital, Derby, UK
  8. 8Northants and Rutland Bowel Cancer Screening Centre, Kettering General Hospital, Kettering, UK
  9. 9NHS Cancer Screening Programmes, Sheffield, UK
  10. 10South of Tyne Bowel Cancer Screening Centre, South Tyneside General Hospital, South Shields, UK
  1. Correspondence to Dr Thomas J W Lee, Institute of Health & Society, Newcastle University, Sir James Spence Institute (Floor 4), Royal Victoria Infirmary, Queen Victoria Road, Newcastle upon Tyne NE1 4LP, UK; tomlee{at}
  1. Contributors TJWL, MDR, RGB, JP and CJR conceived and designed the study. TJWL and CN collected the data. TJWL, RGB and SMM analysed the data. TJWL, MDR, SMM, AFG, AC, RJQMcN and CJR contributed to interpretation of the data. TJWL drafted the original manuscript. All authors contributed to critical revision of the manuscript. All authors approved the final manuscript.

  • Revised 20 July 2011
  • Accepted 10 August 2011
  • Published Online First 22 September 2011


Objectives Colonoscopy is central to colorectal cancer (CRC) screening. Success of CRC screening is dependent on colonoscopy quality. The NHS Bowel Cancer Screening Programme (BCSP) offers biennial faecal occult blood (FOB) testing to 60–74 year olds and colonoscopy to those with positive FOB tests. All colonoscopists in the screening programme are required to meet predetermined standards before starting screening and are subject to ongoing quality assurance. In this study, the authors examine the quality of colonoscopy in the NHS BCSP and describe new and established measures to assess and maintain quality.

Design The NHS BCSP database collects detailed data on all screening colonoscopies. Prospectively collected data from the first 3 years of the programme (August 2006 to August 2009) were analysed. Colonoscopy quality indicators (adenoma detection rate (ADR), polyp detection rate, colonoscopy withdrawal time, caecal intubation rate, rectal retroversion rate, polyp retrieval rate, mean sedation doses, patient comfort scores, bowel preparation quality and adverse event incidence) were calculated along with measures of total adenoma detection.

Results 2 269 983 individuals returned FOB tests leading to 36 460 colonoscopies. Mean unadjusted caecal intubation rate was 95.2%, and mean withdrawal time for normal procedures was 9.2 min. The mean ADR per colonoscopist was 46.5%. The mean number of adenomas per procedure (MAP) was 0.91; the mean number of adenomas per positive procedure (MAP+) was 1.94. Perforation occurred after 0.09% of procedures. There were no procedure-related deaths.

Conclusions The NHS BCSP provides high-quality colonoscopy, as demonstrated by high caecal intubation rate, ADR and comfort scores, and low adverse event rates. Quality is achieved by ensuring BCSP colonoscopists meet a high standard before starting screening and through ongoing quality assurance. Measuring total adenoma detection (MAP and MAP+) as adjuncts to ADR may further enhance quality assurance.


  • Competing interests None.

  • Ethics approval County Durham & Tees Valley 2 Research Ethics Committee.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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