title: Low risk of colorectal cancer and advanced adenomas more than 10 years after negative colonoscopy.
abstract: OBJECTIVE
  Screening colonoscopy is an effective method to reduce the incidence of and mortality from colorectal cancer (CRC). There is little empirical evidence available about the optimal interval for screening, making this a subject of debate. We associated the prevalence of advanced colorectal neoplasms with time since negative colonoscopies.
  
  
  METHODS
  In a study of participants in the German colonoscopy screening program, we determined the prevalence of colorectal neoplasias detected at screening colonoscopy among subjects who had undergone a previous colonoscopy without detection of polyps (negative colonoscopy). Data were compared with that from subjects who had not received colonoscopies.
  
  
  RESULTS
  No CRCs were detected in participants who had a previous negative colonoscopy an average of 11.9 years previously (n = 553), compared with the 8.4 CRC cases expected based on age- and gender-specific prevalences among participants who had not received a colonoscopy (n = 2701; standardized prevalence ratio [SPR] = 0.00; 95% confidence interval [CI]: 0.00-0.55). Prevalence of advanced adenoma was also much lower among subjects who had previous colonoscopies (SPR = 0.42; 95% CI: 0.25-0.68). Adjusted prevalence ratios (95% CIs) for detecting an advanced adenoma were 0.38 (95% CI: 0.16-0.90), 0.34 (95% CI: 0.15-0.74), 0.38 (95% CI: 0.16-0.90), and 0.53 (95% CI: 0.27-1.04) among participants with a negative colonoscopy conducted 1-5, 6-10, 11-15, and >16 years ago, respectively, compared to participants with no previous colonoscopy.
  
  
  CONCLUSIONS
  The low risk of CRC and advanced adenomas after a negative colonoscopy supports suggestions that screening intervals be extended to > or =10 years.
authors.affiliation: Division of Clinical Epidemiology of Aging Research, German Cancer Research Center, Bergheimer Str. 20, D-69115 Heidelberg, Germany. h.brenner@dkfz-heidelberg.de
authors.forename: Hermann
authors.initials: H
authors.lastname: Brenner
authors.forename: Ulrike
authors.initials: U
authors.lastname: Haug
authors.forename: Volker
authors.initials: V
authors.lastname: Arndt
authors.forename: Christa
authors.initials: C
authors.lastname: Stegmaier
authors.forename: Lutz
authors.initials: L
authors.lastname: Altenhofen
authors.forename: Michael
authors.initials: M
authors.lastname: Hoffmeister
mesh_terms: D000236:Adenoma / Q000175:diagnosis* / Q000453:epidemiology / Q000473:pathology; D000368:Aged; D015331:Cohort Studies; D003111:Colonic Polyps / Q000175:diagnosis* / Q000453:epidemiology / Q000473:pathology; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000453:epidemiology / Q000473:pathology; D005260:Female; D005858:Germany / Q000453:epidemiology; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods*; D008875:Middle Aged; D016017:Odds Ratio; D018579:Patient Selection; D011237:Predictive Value of Tests; D015995:Prevalence; D018570:Risk Assessment; D013997:Time Factors