title: Rationale and design of the European Polyp Surveillance (EPoS) trials.
abstract: 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.
  
  
  BACKGROUND
  ClinicalTrials.gov (NCT02319928).
authors.affiliation: Unidad de Gastroenterología. Hospital General Universitario de Alicante, Alicante, Spain.
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authors.lastname: Jover
authors.affiliation: Department of Health Management and Health Economics, University of Oslo, Oslo, Norway.
authors.forename: Michael
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authors.lastname: Bretthauer
authors.affiliation: Gastroenterology and Hepatology, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands.
authors.forename: Evelien
authors.initials: E
authors.lastname: Dekker
authors.affiliation: Department of Health Management and Health Economics, University of Oslo, Oslo, Norway.
authors.forename: Øyvind
authors.initials: Ø
authors.lastname: Holme
authors.affiliation: Department of Health Management and Health Economics, University of Oslo, Oslo, Norway.
authors.forename: Michal F
authors.initials: MF
authors.lastname: Kaminski
authors.affiliation: Department of Health Management and Health Economics, University of Oslo, Oslo, Norway.
authors.forename: Magnus
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authors.lastname: Løberg
authors.affiliation: Department of Epidemiology and Biostatistics, Sloan Kettering Memorial Cancer Center, New York, New York, United States.
authors.forename: Ann G
authors.initials: AG
authors.lastname: Zauber
authors.affiliation: Epidemiology and Biostatistics, Harvard T.H. Chan School of Public Health, and Harvard-MIT Division of Health Sciences and Technology, Boston, Massachusetts, United States.
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Hernán
authors.affiliation: Department of Public Health, Erasmus MC, Rotterdam, the Netherlands.
authors.forename: Iris
authors.initials: I
authors.lastname: Lansdorp-Vogelaar
authors.affiliation: Frontier Science (Scotland) Ltd., Kingussie, United Kingdom.
authors.forename: Annike
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authors.lastname: Sunde
authors.affiliation: Frontier Science (Scotland) Ltd., Kingussie, United Kingdom.
authors.forename: Eleanor
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authors.lastname: McFadden
authors.affiliation: Gastroenterology, University Barcelona, CIBERehd, IDIBAPS, Barcelona, Spain.
authors.forename: Antoni
authors.initials: A
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authors.affiliation: Department of Gastroenterological Oncology, the Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, and Medical Center for Postgraduate Education, Warsaw, Poland.
authors.forename: Jaroslaw
authors.initials: J
authors.lastname: Regula
authors.affiliation: Gastroenterology, Hospital Universitario de Canarias, La Laguna, Spain.
authors.forename: Enrique
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authors.lastname: Quintero
authors.affiliation: Gastroenterology, University Barcelona, CIBERehd, IDIBAPS, Barcelona, Spain.
authors.forename: Maria
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authors.lastname: Pellisé
authors.affiliation: AOU Città della Salute e della Scienza - CPO Piemonte, Turin , Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Senore
authors.affiliation: Department of Health Management and Health Economics, University of Oslo, Oslo, Norway.
authors.forename: Mette
authors.initials: M
authors.lastname: Kalager
authors.affiliation: Instituto Português de Oncologia do Porto, and CINTESIS/Faculty of Medicine, University of Porto, Porto, Portugal.
authors.forename: Mario
authors.initials: M
authors.lastname: Dinis-Ribeiro
authors.affiliation: Department of Health Management and Health Economics, University of Oslo, Oslo, Norway.
authors.forename: Louise
authors.initials: L
authors.lastname: Emilsson
authors.affiliation: Gastroenterology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States.
authors.forename: David F
authors.initials: DF
authors.lastname: Ransohoff
authors.affiliation: Department of Health Management and Health Economics, University of Oslo, Oslo, Norway.
authors.forename: Geir
authors.initials: G
authors.lastname: Hoff
authors.affiliation: Department of Health Management and Health Economics, University of Oslo, Oslo, Norway.
authors.forename: Hans-Olov
authors.initials: HO
authors.lastname: Adami
mesh_terms: D000328:Adult; D000368:Aged; D006801:Humans; D008875:Middle Aged; D000236:Adenoma / Q000473:pathology; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000453:epidemiology / Q000473:pathology; D015994:Incidence; D016609:Neoplasms, Second Primary / Q000453:epidemiology; D011159:Population Surveillance / Q000379:methods; D012107:Research Design / Q000706:statistics & numerical data; D013997:Time Factors; D047368:Tumor Burden; D016032:Randomized Controlled Trials as Topic; D064887:Observational Studies as Topic