title: Prevalence of non-polypoid colorectal neoplasms in southern Brazil.
abstract: OBJECTIVE
  Several studies suggest that non-polypoid lesions (NPL) show higher aggressiveness than polypoid lesions, particularly depressed lesions. The present study aimed to assess the prevalence of NPL and the presence of advanced histology in a Brazilian population.
  
  
  METHODS
  Two thousand and sixty-seven superficial neoplastic lesions diagnosed in 1135 patients were analyzed. Lesions were classified as polypoid and non-polypoid (flat and depressed) types, and evaluated for site, size, and histology (adenoma with grade of dysplasia, or early cancer).
  
  
  RESULTS
  Prevalence of NPL was 46.5%. NPL predominated in the right colon (62.9%), whereas polypoid lesions were detected mainly in the left colon (53.2%) (P < 0.001). NPL had a 34% higher probability of occurring in the right colon than polypoid lesions (P < 0.001). NPL were smaller than polypoid lesions (P = 0.03). There were 208 lesions >10 mm, of which 40 (19.2%) had advanced histology: 13% (18/138) of polypoid lesions; 27.3% (18/66) of flat lesions; and 100% (4/4) of depressed lesions (P < 0.001). Among 1859 neoplasms ≤10 mm, only 18 (1%) had advanced histology, and 15 of them were depressed lesions (P < 0.001). Advanced histology was more commonly detected in NPL than in polypoid lesions (P = 0.007), with significant difference in size (P < 0.001). NPL showed more advanced histology than polypoid lesions (OR 2.06; P = 0.01), especially depressed lesions (OR 36.35; P < 0.001). Among all neoplasms, the prevalence of depressed lesions was 2.2%.
  
  
  CONCLUSIONS
  NPL showed high prevalence and higher aggressiveness than polypoid lesions, especially the depressed type.
authors.affiliation: Department of Endoscopy and Gastroenterology, Santa Casa de Caridade Hospital, Bagé, Brazil.
authors.forename: Carlos Eduardo Oliveira
authors.initials: CE
authors.lastname: dos Santos
authors.forename: Daniele
authors.initials: D
authors.lastname: Malaman
authors.forename: Klaus
authors.initials: K
authors.lastname: Mönkemüller
authors.forename: Tiago
authors.initials: T
authors.lastname: Dos Santos Carvalho
authors.forename: César Vivian
authors.initials: CV
authors.lastname: Lopes
authors.forename: Júlio Carlos
authors.initials: JC
authors.lastname: Pereira-Lima
mesh_terms: D000236:Adenoma / Q000453:epidemiology* / Q000473:pathology*; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D001938:Brazil / Q000453:epidemiology; D015331:Cohort Studies; D003111:Colonic Polyps / Q000453:epidemiology / Q000473:pathology; D003113:Colonoscopy / Q000379:methods*; D015179:Colorectal Neoplasms / Q000453:epidemiology* / Q000473:pathology*; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D015995:Prevalence; D012189:Retrospective Studies; D017678:Sex Distribution
keywords: chromoendoscopy; colorectal cancer; colorectal neoplasm; depressed lesion; non-polypoid colorectal neoplasm