title: Colorectal neoplasia screening with CT colonography in average-risk asymptomatic subjects: community-based study.
abstract: OBJECTIVE
  To evaluate computed tomographic (CT) colonography as a screening tool for average-risk asymptomatic subjects with regard to participation, acceptability, and safety.
  
  
  METHODS
  CT colonography for colorectal neoplasia screening was offered to 2,000 subjects aged 50-54 and 65-69 years. Only asymptomatic subjects at average risk of colorectal neoplasia were enrolled. Participants underwent CT colonography followed by colonoscopy if CT colonography findings showed any polyps. Acceptability was measured with a 100-point (0, most favorable; 100, least favorable) visual analogue scale (VAS). Chi2 statistic was used to compare participation rates among subgroups. Safety of CT colonography was evaluated by recording all important adverse events.
  
  
  RESULTS
  A total of 1,452 subjects were eligible for screening. The adjusted participation rate was 28.4%. Participation was higher in younger subjects and in those from a high socioeconomic region. Major reasons for nonparticipation were insufficient time and perceived good health. Median VAS scores for pain, general satisfaction, embarrassment, and willingness to repeat screening were 13, 6, 8, and 5, respectively. Most subjects found CT colonography better than (60%) or same as (32%) expected. Ninety-three (27.4%) of 340 subjects were referred for colonoscopy, with polyps found in 67 (positive predictive value, 0.73). By adopting criteria that a positive finding at CT colonography is that of a single polyp larger than 5 mm or multiple polyps larger than 2 mm, 14% of CT examinations would have led to colonoscopy; 5.7% of CT findings were false-positive, with no significant impairment in large polyp detection. There were no important adverse events related to CT colonography, although four subjects had syncope or presyncope related to bowel preparation.
  
  
  CONCLUSIONS
  Community-based colorectal neoplasia screening with CT colonography was accompanied by a participation rate that compares favorably with that of similar screening programs. CT colonography was highly acceptable to participants.
authors.affiliation: Department of Gastroenterology and Hepatology, Royal Perth Hospital, Box X2213 GPO Perth, Western Australia 6000. john.t.edwards@health.wa.gov.au
authors.forename: John T
authors.initials: JT
authors.lastname: Edwards
authors.forename: Richard M
authors.initials: RM
authors.lastname: Mendelson
authors.forename: Lin
authors.initials: L
authors.lastname: Fritschi
authors.forename: Noellene M
authors.initials: NM
authors.lastname: Foster
authors.forename: Christopher
authors.initials: C
authors.lastname: Wood
authors.forename: Dianne
authors.initials: D
authors.lastname: Murray
authors.forename: Geoffrey M
authors.initials: GM
authors.lastname: Forbes
mesh_terms: D000368:Aged; D003111:Colonic Polyps / Q000000981:diagnostic imaging*; D023881:Colonography, Computed Tomographic; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D010342:Patient Acceptance of Health Care; D011237:Predictive Value of Tests; D012307:Risk Factors; D014904:Western Australia