title: Harms of colonoscopy in a colorectal cancer screening programme with faecal occult blood test: a population-based cohort study.
abstract: OBJECTIVE
  To assess the harms of colonoscopy in a real world colorectal cancer screening programme with faecal occult blood test.
  
  
  METHODS
  Retrospective cohort study of all colonoscopies performed in patients aged 50-74 for a positive guaiac-based faecal occult blood test between September 2003 and February 2010 within the screening programme in progress in Alsace (France). Adverse events were recorded through prospective voluntary reporting by gastroenterologists and retrospective postal surveys addressed to persons screened and their general practitioners.
  
  
  RESULTS
  Of 10,277 colonoscopies, 250 adverse events were recorded, 48 (4.7 ‰, 95% CI 3.4-6.0) of them being moderate or severe, mainly 10 (1.0 ‰, 95% CI 0.4-1.6) perforations and 31 (3.0 ‰, 95% CI 2.0-4.1) bleeding. 91.7% of moderate and severe adverse events were the result of a therapeutic procedure. Of 103 serious adverse events, eight (7.8%) were considered preventable. Gastroenterologists reported 52.2% of moderate and severe adverse events. A mild adverse event or an incident was reported in up to 97.0 ‰ (95% CI 83.2-110.7) colonoscopies.
  
  
  CONCLUSIONS
  The harms of colonoscopy were underestimated in all randomized controlled trials on colorectal cancer screening with faecal occult blood test. They are greater in a real world programme, estimated at 7.5 major and 100 minor adverse events per 1000 colonoscopies.
authors: Department of Gastroenterology, Pasteur Hospital, 39 avenue de la Liberté, Colmar, France. bernard.denis@ch-colmar.fr
authors: Bernard
authors: B
authors: Denis
authors: Isabelle
authors: I
authors: Gendre
authors: Erik André
authors: EA
authors: Sauleau
authors: Joël
authors: J
authors: Lacroute
authors: Philippe
authors: P
authors: Perrin
mesh_terms: D000368:Aged; D015331:Cohort Studies; D003106:Colon; D003113:Colonoscopy / Q000009:adverse effects* / Q000706:statistics & numerical data; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000517:prevention & control; D005260:Female; D005602:France; D006470:Hemorrhage / Q000209:etiology; D006801:Humans; D007416:Intestinal Perforation / Q000209:etiology; D008297:Male; D008403:Mass Screening / Q000706:statistics & numerical data*; D008875:Middle Aged; D009780:Occult Blood; D011446:Prospective Studies; D016032:Randomized Controlled Trials as Topic; D012189:Retrospective Studies; D011795:Surveys and Questionnaires