Population-Based Colonoscopy Screening for Colorectal Cancer: A Randomized Clinical Trial.

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.

Rationale and design of the European Polyp Surveillance (EPoS) trials.

BACKGROUND: Current guidelines recommend surveillance colonoscopies after polyp removal depending on the number and characteristics of polyps, but there is a lack of evidence supporting the recommendations. This report outlines the rationale and design of two randomized trials and one observational study investigating evidence-based surveillance strategies following polyp removal. Study design and endpoints: The EPoS studies started to recruit patients in April 2015. EPoS study I randomizes 13 746 patients with low-risk adenomas (1 - 2 tubular adenomas size < 10 mm, low-grade dysplasia) to surveillance after 5 and 10 years, or 10 years only. EPoS study II randomizes 13 704 patients with high-risk adenomas (3 - 10 adenomas or adenoma ≥ 10 mm in diameter, or adenoma with high-grade dysplasia, or > 25 % villous features) to surveillance after 3, 5, and 10 years, or 5 and 10 years only. EPoS study III offers surveillance after 5 and 10 years to patients with serrated polyps ≥ 10 mm in diameter at any location, or serrated polyps ≥ 5 mm in diameter proximal to the splenic flexure. All polyps are removed before patients enter the trials. The primary end point is colorectal cancer incidence after 10 years. We assume a colorectal cancer risk of 1 % for patients in EPoS I, and 2 % for patients in EPoS II. Using a noninferiority hypothesis with an equivalence interval of 0.5 % for EPoS I and 0.7 % for EPoS II, the trials are 90 % powered to uncover differences larger than the equivalence intervals. For EPoS III, no power analyses have been performed. CONCLUSIONS: The present trials aim to develop evidence-based strategies for polyp surveillance, thereby maximizing effectiveness and minimizing resources. TRIAL REGISTRATION: ClinicalTrials.gov (NCT02319928).