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Original Investigation
July 2016

Population-Based Colonoscopy Screening for Colorectal CancerA Randomized Clinical Trial

Author Affiliations
  • 1Department of Health Management and Health Economy, University of Oslo, Oslo, Norway
  • 2Department of Transplantation Medicine and KG Jebsen Center for Colorectal Cancer Research, Oslo University Hospital, Oslo, Norway
  • 3Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA
  • 4Department of Gastroenterological Oncology, The Maria Sklodowska Curie Memorial Cancer Center and Institute of Oncology and Medical Center for Postgraduate Education, Warsaw, Poland
  • 5Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York, NY
  • 6Department of Gastroenterology and Hepatology, Erasmus Medical Centre, Rotterdam, the Netherlands
  • 7Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA
  • 8Division of Health Sciences and Technology, Harvard–Massachusetts Institute of Technology, Boston
  • 9Frontier Science Scotland, Kincraig, UK
  • 10Department of Gastroenterology and Hepatology, Academic Medical Centre, Amsterdam, the Netherlands
  • 11Department of Medicine, Sørlandet Hospital, Arendal, Norway
  • 12Department of Surgery, The National University Hospital of Iceland, Reykjavik, Iceland
  • 13Department of Research and Development, Telemark Hospital, Skien, Norway
  • 14Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
JAMA Intern Med. 2016;176(7):894-902. doi:10.1001/jamainternmed.2016.0960

Importance  Although some countries have implemented widespread colonoscopy screening, most European countries have not introduced it because of uncertainty regarding participation rates, procedure-related pain and discomfort, endoscopist performance, and effectiveness. To our knowledge, no randomized trials on colonoscopy screening currently exist.

Objective  To investigate participation rate, adenoma yield, performance, and adverse events of population-based colonoscopy screening in several European countries.

Design, Setting, and Population  A population-based randomized clinical trial was conducted among 94 959 men and women aged 55 to 64 years of average risk for colon cancer in Poland, Norway, the Netherlands, and Sweden from June 8, 2009, to June 23, 2014.

Interventions  Colonoscopy screening or no screening.

Main Outcomes and Measures  Participation in colonoscopy screening, cancer and adenoma yield, and participant experience. Study outcomes were compared by country and endoscopist.

Results  Of 31 420 eligible participants randomized to the colonoscopy group, 12 574 (40.0%) underwent screening. Participation rates were 60.7% in Norway (5354 of 8816), 39.8% in Sweden (486 of 1222), 33.0% in Poland (6004 of 18 188), and 22.9% in the Netherlands (730 of 3194) (P < .001). The cecum intubation rate was 97.2% (12 217 of 12 574), with 9726 participants (77.4%) not receiving sedation. Of the 12 574 participants undergoing colonoscopy screening, we observed 1 perforation (0.01%), 2 postpolypectomy serosal burns (0.02%), and 18 cases of bleeding owing to polypectomy (0.14%). Sixty-two individuals (0.5%) were diagnosed with colorectal cancer and 3861 (30.7%) had adenomas, of which 1304 (10.4%) were high-risk adenomas. Detection rates were similar in the proximal and distal colon. Performance differed significantly between endoscopists; recommended benchmarks for cecal intubation (95%) and adenoma detection (25%) were not met by 6 (17.1%) and 10 of 35 endoscopists (28.6%), respectively. Moderate or severe abdominal pain after colonoscopy was reported by 601 of 3611 participants (16.7%) examined with standard air insufflation vs 214 of 5144 participants (4.2%) examined with carbon dioxide (CO2) insufflation (P < .001).

Conclusions and Relevance  Colonoscopy screening entails high detection rates in the proximal and distal colon. Participation rates and endoscopist performance vary significantly. Postprocedure abdominal pain is common with standard air insufflation and can be significantly reduced by using CO2.

Trial Registration  clinicaltrials.gov Identifier: NCT00883792