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

Endoscopy. 2016 Jun;48(6):571-8. doi: 10.1055/s-0042-104116. Epub 2016 Apr 4.


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).

Publication types

  • Observational Study
  • Randomized Controlled Trial

MeSH terms

  • Adenoma / pathology*
  • Adult
  • Aged
  • Colonoscopy*
  • Colorectal Neoplasms / epidemiology*
  • Colorectal Neoplasms / pathology*
  • Humans
  • Incidence
  • Middle Aged
  • Neoplasms, Second Primary / epidemiology*
  • Population Surveillance / methods
  • Research Design* / statistics & numerical data
  • Time Factors
  • Tumor Burden

Associated data

  • ClinicalTrials.gov/NCT02319928