title: Definition and taxonomy of interval colorectal cancers: a proposal for standardising nomenclature.
abstract: OBJECTIVE
  Interval colorectal cancers (interval CRCs), that is, cancers occurring after a negative screening test or examination, are an important indicator of the quality and effectiveness of CRC screening and surveillance. In order to compare incidence rates of interval CRCs across screening programmes, a standardised definition is required. Our goal was to develop an internationally applicable definition and taxonomy for reporting on interval CRCs.
  
  
  METHODS
  Using a modified Delphi process to achieve consensus, the Expert Working Group on interval CRC of the Colorectal Cancer Screening Committee of the World Endoscopy Organization developed a nomenclature for defining and characterising interval CRCs.
  
  
  RESULTS
  We define an interval CRC as a "colorectal cancer diagnosed after a screening or surveillance exam in which no cancer is detected, and before the date of the next recommended exam". Guidelines and principles for describing and reporting on interval CRCs are provided, and clinical scenarios to demonstrate the practical application of the nomenclature are presented.
  
  
  CONCLUSIONS
  The Working Group on interval CRC of the World Endoscopy Organization endorses adoption of this standardised nomenclature. A standardised nomenclature will facilitate benchmarking and comparison of interval CRC rates across programmes and regions.
authors.affiliation: Division of Gastroenterology and Hepatology, Department of Internal Medicine; and GROW, School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht The Netherlands.
authors.forename: S
authors.initials: S
authors.lastname: Sanduleanu
authors.affiliation: Division of Gastroenterology and Hepatology, Department of Internal Medicine; and GROW, School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht The Netherlands.
authors.forename: C M C
authors.initials: CM
authors.lastname: le Clercq
authors.affiliation: Department of Gastroenterology and Hepatology, Academic Medical Center Amsterdam, Amsterdam, The Netherlands.
authors.forename: E
authors.initials: E
authors.lastname: Dekker
authors.affiliation: Department of Pathology, VU University Medical Center Amsterdam, Amsterdam, The Netherlands.
authors.forename: G A
authors.initials: GA
authors.lastname: Meijer
authors.affiliation: Department of Medicine, University of Toronto; and Cancer Care Ontario, Toronto, Ontario, Canada.
authors.forename: L
authors.initials: L
authors.lastname: Rabeneck
authors.affiliation: Department of Gastroenterology, University Hospital of North Tees, Stockton-on-Tees, Cleveland, UK; and Durham University School of Medicine, Pharmacy and Health, Stockton-on-Tees, Cleveland, UK.
authors.forename: M D
authors.initials: MD
authors.lastname: Rutter
authors.affiliation: Gloucestershire Royal Hospital, Gloucester, UK.
authors.forename: R
authors.initials: R
authors.lastname: Valori
authors.affiliation: Flinders Centre for Innovation in Cancer, Flinders University, Adelaide, Australia.
authors.forename: G P
authors.initials: GP
authors.lastname: Young
authors.affiliation: Division of Gastroenterology, Hepatology and Nutrition, University of Pittsburgh Medical Center, Pittsburgh, USA.
authors.forename: R E
authors.initials: RE
authors.lastname: Schoen
mesh_terms: D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000145:classification* / Q000175:diagnosis*; D055088:Early Detection of Cancer / Q000379:methods*; D006801:Humans; D008403:Mass Screening; D009626:Terminology as Topic
keywords: COLORECTAL CANCER; SCREENING