title: Incidence of Interval Colorectal Cancer Among Inflammatory Bowel Disease Patients Undergoing Regular Colonoscopic Surveillance.
abstract: OBJECTIVE
  Surveillance is recommended for patients with long-term inflammatory bowel disease because they have an increased risk of colorectal cancer (CRC). To study the effectiveness of surveillance, we determined the incidence of CRC after negative findings from surveillance colonoscopies (interval CRC).
  
  
  METHODS
  We collected data from 1273 patients with ulcerative colitis or Crohn's disease, enrolled in a surveillance program at 7 hospitals in The Netherlands, who underwent 4327 surveillance colonoscopies from January 1, 2000, through January 1, 2014. Patients were followed up from their first surveillance colonoscopy until the last surveillance colonoscopy, colectomy, or CRC. Factors that might have contributed to the occurrence of CRC were categorized as inadequate procedures (ie, inadequate bowel preparation), inadequate surveillance (CRC occurring outside the appropriate surveillance interval), or inadequate management of dysplasia (CRC diagnosed in the same colonic segment as a previous diagnosis of dysplasia). The remaining CRC cases were classified as true interval CRCs.
  
  
  RESULTS
  CRC was diagnosed in 17 patients (1.3%), with an incidence of 2.5 per 1000 years of follow-up evaluation. Factors that might account for the occurrence of CRC were identified in 12 patients (70%). These were inadequate colonoscopies in 4 patients (24%), inadequate surveillance intervals in 9 patients (53%), and inadequate management of dysplasia in 2 patients (12%). The remaining 5 cases of CRC (30%) were classified as true interval CRCs.
  
  
  CONCLUSIONS
  In a retrospective analysis of patients with inflammatory bowel disease participating in a surveillance program, the incidence of CRC was only 1%, which supports the implementation of longer surveillance intervals. However, the fact that 30% of CRC cases were interval cancers indicates the need for variable surveillance intervals based on risk factors for CRC.
authors.affiliation: Department of Gastroenterology and Hepatology, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Erik
authors.initials: E
authors.lastname: Mooiweer
authors.affiliation: Department of Gastroenterology and Hepatology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Andrea E
authors.initials: AE
authors.lastname: van der Meulen-de Jong
authors.affiliation: Department of Gastroenterology and Hepatology, Amsterdam Medical Center, Amsterdam, The Netherlands.
authors.forename: Cyriel Y
authors.initials: CY
authors.lastname: Ponsioen
authors.affiliation: Department of Gastroenterology and Hepatology, Erasmus Medical Center Rotterdam, Rotterdam, The Netherlands.
authors.forename: C Janneke
authors.initials: CJ
authors.lastname: van der Woude
authors.affiliation: Department of Gastroenterology and Hepatology, Vrije Universiteit Medical Center Amsterdam, Amsterdam, The Netherlands.
authors.forename: Ad A
authors.initials: AA
authors.lastname: van Bodegraven
authors.affiliation: Department of Gastroenterology and Hepatology, Onze Lieve Vrouwe Gasthuis Amsterdam, Amsterdam, The Netherlands.
authors.forename: Jeroen M
authors.initials: JM
authors.lastname: Jansen
authors.affiliation: Department of Gastroenterology and Hepatology, St Antonius Hospital Nieuwegein, Nieuwegein, The Netherlands.
authors.forename: Nofel
authors.initials: N
authors.lastname: Mahmmod
authors.affiliation: Department of Gastroenterology and Hepatology, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Willemijn
authors.initials: W
authors.lastname: Kremer
authors.affiliation: Department of Gastroenterology and Hepatology, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Peter D
authors.initials: PD
authors.lastname: Siersema
authors.affiliation: Department of Gastroenterology and Hepatology, University Medical Center Utrecht, Utrecht, The Netherlands. Electronic address: b.oldenburg@umcutrecht.nl.
authors.forename: Bas
authors.initials: B
authors.lastname: Oldenburg
mesh_terms: D000328:Adult; D003113:Colonoscopy / Q000379:methods; D015179:Colorectal Neoplasms / Q000453:epidemiology*; D055088:Early Detection of Cancer / Q000379:methods; D062665:Epidemiological Monitoring; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D015212:Inflammatory Bowel Diseases / Q000150:complications*; D008297:Male; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D012189:Retrospective Studies; D013997:Time Factors
keywords: Inflammatory Bowel Disease; Interval Colorectal Cancer; Surveillance