title: Histological features of advanced colorectal adenomas detected by endoscopy and fecal immunochemical test.
abstract: OBJECTIVE
  The detection of advanced adenomas within organized screening programs using either immunochemical fecal occult blood test (FIT) or endoscopy has been associated with the prevention of colorectal cancer. The histological changes and pathogenetic mechanisms that lead to the detection of such lesions by either of these screening methods have not yet been addressed.
  
  
  METHODS
  The histological specimens of 50 advanced adenomas detected by FIT were compared with those of 50 advanced adenomas detected by primary endoscopy screening that were matched for size and histology. The following variables were systematically recorded: 1) histopathological changes compatible with luminal bleeding induced by ischemia; 2) hypoxia in the adenomatous tissue, assessed through the expression of carbonic anhydrase IX; and 3) microvessel quantitative analysis, evaluated by CD31 and CD105 immunostains. All specimens were reviewed blindly by an expert gastrointestinal pathologist.
  
  
  RESULTS
  Histopathological changes associated with ischemia-related luminal bleeding were significantly more frequent in FIT-positive than in endoscopy-detected advanced adenomas (78 % vs. 14 %; P < 0.001). Carbonic anhydrase IX expression was also significantly higher in FIT-detected advanced adenomas (immunohistochemical score: 12.0 vs. 4.1; P < 0.001). Conversely, no differences were found in microvessel density.
  
  
  CONCLUSIONS
  The detection of advanced adenomas by FIT screening appears to be related to ischemia-associated luminal bleeding, which, in turn, may be due to periods of hypoxia. The absence of such changes in endoscopy-detected advanced adenomas would suggest that the two screening methods may be complementary for the detection of advanced neoplasia within organized screening programs.
authors.affiliation: Unit of Pathology, Candiolo Cancer Institute - FPO, IRCCS, Candiolo, Italy.
authors.forename: Mauro
authors.initials: M
authors.lastname: Risio
authors.affiliation: Unit of Epidemiology, Centre for Cancer Prevention, Turin, Italy.
authors.forename: Cesare
authors.initials: C
authors.lastname: Hassan
authors.affiliation: Unit of Clinical Biochemistry, Candiolo Cancer Institute - FPO, IRCCS, Candiolo, Italy.
authors.forename: Antonino
authors.initials: A
authors.lastname: Sottile
authors.affiliation: Unit of Pathology, Candiolo Cancer Institute - FPO, IRCCS, Candiolo, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Saglia
authors.affiliation: Unit of Epidemiology, Centre for Cancer Prevention, Turin, Italy.
authors.forename: Nereo
authors.initials: N
authors.lastname: Segnan
authors.affiliation: Unit of Epidemiology, Centre for Cancer Prevention, Turin, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Senore
mesh_terms: D000236:Adenoma / Q000175:diagnosis*; D000368:Aged; D044682:Colon, Ascending / Q000473:pathology; D044683:Colon, Descending / Q000473:pathology; D012809:Colon, Sigmoid / Q000473:pathology; D003113:Colonoscopy / Q000379:methods*; D015179:Colorectal Neoplasms / Q000175:diagnosis*; D055088:Early Detection of Cancer; D005260:Female; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging / Q000379:methods*; D009780:Occult Blood; D015203:Reproducibility of Results; D012812:Sigmoidoscopy / Q000379:methods