title: The role of adenoma for colorectal cancer development: differences in the distribution of adenoma with low-grade dysplasia, high-grade dysplasia, and cancer that invades the submucosa.
abstract: BACKGROUND
  The purpose of this study was to elucidate the role of adenoma in the early stage of colorectal cancer development, we focused on the clinicopathologic relationship between adenoma with low-grade dysplasia (ALGD), adenoma with high-grade dysplasia (AHGD), and cancer that invades the submucosa in the colorectum.
  
  
  METHODS
  We clinicopathologically examined a total of 553 adenomas and 58 cancers that invaded the submucosa. The tissues were excised from 479 patients who underwent total colonoscopy.
  
  
  RESULTS
  The percentage of ALGD was 79.9% in the proximal colon, 70.5% in the distal colon, and 48.3% in the rectum, respectively. The percentages of AHGD and cancer were 14.5% and 5.6% in the proximal colon, 21.3% and 8.2% in the distal colon, and 35.4% and 16.3% in the rectum, respectively. In contrast with the distribution of ALGD, the distribution of both AHGD and cancer shifted from the proximal to the distal site, with a statistical significance (P <.01). When the distribution of adenoma was compared according to tumor size, both large- and small-sized AHGD showed a similar cancer distribution, however, both large- and small-sized ALGD showed different distributions.
  
  
  CONCLUSIONS
  An important role of AHGD for cancer development in the colorectum may relate to the similar distribution between AHGD and cancer; however, the different distributions observed between ALGD, AHGD, and cancer suggested that ALGD has only a slight association with the development of cancer.
authors.affiliation: Department of Surgery and Clinical Research Institute, National Kyushu Medical Center, Fukuoka, Japan.
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Ikeda
authors.forename: Masaki
authors.initials: M
authors.lastname: Mori
authors.forename: Kotaro
authors.initials: K
authors.lastname: Shibahara
authors.forename: Akinori
authors.initials: A
authors.lastname: Iwashita
authors.forename: Yukiaki
authors.initials: Y
authors.lastname: Haraguchi
authors.forename: Motonori
authors.initials: M
authors.lastname: Saku
mesh_terms: D000236:Adenoma / Q000453:epidemiology / Q000473:pathology*; D003106:Colon / Q000473:pathology; D015179:Colorectal Neoplasms / Q000453:epidemiology / Q000473:pathology*; D006801:Humans; D007413:Intestinal Mucosa / Q000473:pathology*; D009361:Neoplasm Invasiveness / Q000473:pathology; D012007:Rectum / Q000473:pathology; D012189:Retrospective Studies