title: Interval colorectal cancer after colonoscopy.
abstract: BACKGROUND
  As more patients are screened for colorectal cancer a small but significant number of interval cancers develop after colonoscopy for colorectal cancer screening.
  
  
  METHODS
  We reviewed records of 75,314 adult patients who underwent colonoscopy for screening or diagnostic purposes between 1998 and 2006 inclusively, and identified 77 who developed interval cancers within the next 5 years. We reviewed their original endoscopic findings to determine the clinical and endoscopic factors that might predict a greater risk for future cancers.
  
  
  RESULTS
  Patients aged ≥ 60 years had a higher risk of an interval neoplasm (P < .0001). Interval cancers were more common on the right side of the colon and in the hepatic flexure (both P < .0001). We did not observe an increased rate of interval cancers in patients with poor preparation (P = .799); however, examination completion rates did affect the rate of interval cancers (P = .016).
  
  
  CONCLUSIONS
  Better identification of higher risk patients and assurance of follow-up examinations might increase the percentage of colon cancers discovered at an early stage. Special attention to careful examination of the right colon is key.
authors.affiliation: Gastrointestinal Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA. Electronic address: jrichter@mgh.harvard.edu.
authors.forename: James M
authors.initials: JM
authors.lastname: Richter
authors.affiliation: Gastrointestinal Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA.
authors.forename: Emily J
authors.initials: EJ
authors.lastname: Campbell
authors.affiliation: Gastrointestinal Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA.
authors.forename: Daniel C
authors.initials: DC
authors.lastname: Chung
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003113:Colonoscopy / Q000379:methods*; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000453:epidemiology; D055088:Early Detection of Cancer / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods*; D008875:Middle Aged; D012189:Retrospective Studies; D013997:Time Factors; D055815:Young Adult
keywords: Cancer screening; Colonoscopy; Colorectal cancer; Interval cancer; Quality