title: Colonoscopic screening of an average-risk population for colorectal neoplasia.
abstract: OBJECTIVE
  The role of screening colonoscopy in an asymptomatic, average-risk population remains to be determined. Moreover, the value of screening colonoscopy in individuals older than 75 years and for right-sided lesions has recently been questioned. The aims were to assess: (i) the risk of colorectal neoplasia in a large consecutively screened asymptomatic average-risk population, aged 40-85 years; (ii) whether colonoscopy is better than sigmoidoscopy for primary screening; and (iii) the prevalence of right-sided lesions at different ages.
  
  
  METHODS
  This prospective study, analyzed data from 1563 consecutive, asymptomatic, average-risk individuals, aged 40-85 years, who underwent screening colonoscopy.
  
  
  RESULTS
  Overall, neoplastic lesions were detected in 262 individuals (17% of the study population), of whom 75 had advanced lesions (5% of population) and nine had colorectal cancers (CRC) (0.6% of population). The prevalence of all lesions increased with age, with the highest percentages in the > 75 age group (26.5% with neoplastic and 6 % with advanced lesions). Higher age was also associated with relatively more right-sided lesions. In particular the prevalence of proximal neoplasia, without concurrent distal neoplasia, increased from 5% in those < 50 years to 24% in those > 75 years. Those with distal lesions had a higher overall risk for proximal lesions (odds ratio [OR] 3.2); nevertheless flexible sigmoidoscopy alone would have missed up to 40% of all lesions and up to 3.5% of advanced neoplastic lesions in this patient subgroup.
  
  
  CONCLUSIONS
  Screening colonoscopy in asymptomatic, average-risk individuals is mandatory, as noteworthy numbers of advanced colorectal neoplasias have been detected in all age groups, especially in those aged > 75. Most importantly, many of the detected lesions were proximal and would not be revealed by sigmoidoscopy alone.
authors.affiliation: Department of Cancer Prevention, Tel Aviv Medical Center and Sackler School of Medicine, Tel Aviv University, Israel.
authors.forename: B
authors.initials: B
authors.lastname: Boursi
authors.forename: A
authors.initials: A
authors.lastname: Halak
authors.forename: M
authors.initials: M
authors.lastname: Umansky
authors.forename: L
authors.initials: L
authors.lastname: Galzan
authors.forename: H
authors.initials: H
authors.lastname: Guzner-Gur
authors.forename: N
authors.initials: N
authors.lastname: Arber
mesh_terms: D000328:Adult; D000368:Aged; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D015995:Prevalence; D012307:Risk Factors; D012812:Sigmoidoscopy