title: Long-term risk of colorectal cancer after adenoma removal: a population-based cohort study.
abstract: BACKGROUND
  Previous studies examining the incidence of colorectal cancer after polypectomy have provided discordant findings. The aim of this study was to compare the risk of colorectal cancer after adenoma removal in routine clinical practice with the risk in the general population.
  
  
  METHODS
  Cohort study based on detailed data from a population-based registry that has collected all cases of both colorectal cancers and adenomas diagnosed in a clearly-defined population since 1976.
  
  
  METHODS
  French administrative area of Côte-d'Or (Burgundy).
  
  
  METHODS
  Residents of the area diagnosed for the first time with colorectal adenoma between 1990 and 1999 were included (n=5779). Initial and follow-up data until December 2003 were used to calculate the colorectal cancer standardised incidence ratio (SIR) and cumulative probabilities after adenoma removal.
  
  
  RESULTS
  After a median follow-up of 7.7 years, 87 invasive colorectal cancers were diagnosed whereas 69 cases were expected. Compared with the general population, the overall SIR was 1.26 (95% CI 1.01 to 1.56). The risk of colorectal cancer depended on the characteristics of the initial adenoma (SIR 2.23 (95% CI 1.67 to 2.92) for advanced adenomas and 0.68 (95% CI 0.44 to 0.99) for non-advanced adenomas). In cases of advanced adenomas, the SIR was 1.10 (95% CI 0.62 to 1.82) in patients with colonoscopic follow-up and 4.26 (95% CI 2.89 to 6.04) in those without. The 10-year cumulative probabilities of colorectal cancer were, respectively, 2.05% (95% CI 1.14% to 3.64%) and 6.22% (95% CI 4.26% to 9.02%).
  
  
  CONCLUSIONS
  In routine practice, the risk of colorectal cancer after adenoma removal remains high and depends both on initial adenoma features and on colonoscopy surveillance practices. Gastroenterologists should encourage patients to comply with long-term colonoscopic surveillance.
authors: INSERM, UMR 866, Faculté de Médecine, BP 87900, F-21079 Dijon Cedex, France. vanessa.cottet@u-bourgogne.fr
authors: Vanessa
authors: V
authors: Cottet
authors: Valérie
authors: V
authors: Jooste
authors: Isabelle
authors: I
authors: Fournel
authors: Anne-Marie
authors: AM
authors: Bouvier
authors: Jean
authors: J
authors: Faivre
authors: Claire
authors: C
authors: Bonithon-Kopp
mesh_terms: D000236:Adenoma / Q000453:epidemiology / Q000473:pathology / Q000601:surgery*; D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000175:diagnosis / Q000453:epidemiology*; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D005602:France / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011159:Population Surveillance; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D015996:Survival Rate / Q000639:trends; D013997:Time Factors