title: The co-localization of carcinomas and adenomas favors a regional field defect in the colon: an observational study.
abstract: OBJECTIVE
  Finding common genetic alterations in colorectal cancers (CRCs) and peri-tumoral mucosa first led to the notion of colonic field defects. The hypothesis of a genetically determined mosaicism would explain these defects and would make the co-localization of tumors likely. Our purpose was to indirectly test this hypothesis by searching for a possible correlation between the location of colorectal cancers and adenomas
  
  
  METHODS
  This is a retrospective observational study. Patients operated for colorectal cancers at an oncological hospital, who had a full colonoscopy performed in the two peri-operative years, were surveyed. Sex, age, familial risk of cancer, tumor and adenoma locations, and the presence of adenomas larger than 1 cm, with villous component or high-grade dysplasia were recorded.
  
  
  METHODS
  T test, chi-square, exact, logistic regression (SPSS18®).
  
  
  RESULTS
  This study included 224 patients (57 % male, mean age 67.6 years), 45 % of which had synchronous adenomas. There was a significant correlation between cancer location and location of all adenomas (p = 0.01) and of adenomas larger than 1 cm (p = 0.01). Adenomas of the right colon were more frequent in patients with right colon cancer (p = 0.008), and the same was true on the left colon (p = 0.002).
  
  
  CONCLUSIONS
  The strong correlation between the locations of CRC and synchronous adenomas, namely risk adenomas, may point to a common early defect. It does also suggest that hemicolectomy may always be the surgery of choice for colon cancer.
authors.affiliation: Serviço de Gastrenterologia do Instituto Português de Oncologia de Lisboa, Francisco Gentil (IPOLFG), EPE, Rua Professor Lima Basto, 1099-023, Lisbon, Portugal, isaalr9@zonmail.pt.
authors.forename: Isadora
authors.initials: I
authors.lastname: Rosa
authors.forename: Paulo
authors.initials: P
authors.lastname: Fidalgo
authors.forename: Paula
authors.initials: P
authors.lastname: Chaves
authors.forename: António D
authors.initials: AD
authors.lastname: Pereira
mesh_terms: D000236:Adenoma / Q000473:pathology*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002277:Carcinoma / Q000473:pathology*; D015179:Colorectal Neoplasms / Q000235:genetics / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009030:Mosaicism; D009378:Neoplasms, Multiple Primary / Q000473:pathology*; D012189:Retrospective Studies; D012307:Risk Factors