title: Risk factors associated with colorectal flat adenoma detection.
abstract: OBJECTIVE
  Colorectal flat adenomas have been associated with a higher risk of colorectal malignancy. We describe demographic characteristics and endoscopic findings in patients with colorectal flat adenomas.
  
  
  METHODS
  In total, 1934 consecutive patients undergoing colonoscopy were prospectively included. Polyp shape was classified according to the Japanese classification. Chromoendoscopy was applied whenever a flat lesion was suspected. Indications for colonoscopy, demographic data, and characteristics of neoplastic lesions were recorded. Patients were classified as follows: group 1, no adenomas (n=1250); group 2, only protruding adenomas (n=427); group 3, protruding and flat adenomas (n=118); and group 4, only flat adenomas (n=139).
  
  
  RESULTS
  Approximately one in every 10 patients (13.2%) had flat adenomas. Among them, concomitant protruding adenomas were identified in approximately half of the cases. In multivariate analysis, age older than 50 years [odds ratio (OR)=1.62; 95% confidence interval (CI)=1.08-2.43, P=0.02], protruding adenomas (OR=2.17; 95% CI=1.65-2.87, P<0.001), follow-up colonoscopy for polyps or cancer (OR=2.22; 95% CI=1.59-3.10, P<0.001), screening colonoscopy (OR=1.60, 95% CI=1.15-2.22, P=0.005), and specifically trained endoscopist (OR=2.02, 95% CI=1.53-2.68, P<0.001) were associated independently with flat adenoma detection.
  
  
  CONCLUSIONS
  Flat adenomas have specific demographic factors that might help to improve detection. Particularly, age older than 50 years, colorectal neoplasia surveillance, and the presence of protruding adenomas should alert endoscopists to the possible presence of these lesions. Trained endoscopists may offer a greater chance of detecting these lesions.
authors.affiliation: Department of Gastroenterology, Hospital Universitario de Canarias, La Laguna, Tenerife, Spain. dnicolasp@telefonica.net
authors.forename: David
authors.initials: D
authors.lastname: Nicolás-Pérez
authors.forename: Adolfo
authors.initials: A
authors.lastname: Parra-Blanco
authors.forename: Antonio Z
authors.initials: AZ
authors.lastname: Gimeno-García
authors.forename: Juan A
authors.initials: JA
authors.lastname: Ortega-Sánchez
authors.forename: Marta
authors.initials: M
authors.lastname: Carrillo-Palau
authors.forename: Alejandro
authors.initials: A
authors.lastname: Jiménez-Sosa
authors.forename: Enrique
authors.initials: E
authors.lastname: Quintero-Carrion
mesh_terms: D000236:Adenoma / Q000453:epidemiology / Q000473:pathology*; D018256:Adenomatous Polyps / Q000453:epidemiology / Q000473:pathology*; D000328:Adult; D000367:Age Factors; D000368:Aged; D016009:Chi-Square Distribution; D002983:Clinical Competence; D003111:Colonic Polyps / Q000453:epidemiology / Q000473:pathology*; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000453:epidemiology / Q000473:pathology*; D055088:Early Detection of Cancer; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D011237:Predictive Value of Tests; D015995:Prevalence; D011379:Prognosis; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013030:Spain / Q000453:epidemiology