title: Colonic adenoma risk in familial colorectal cancer--a study of six extended kindreds.
abstract: OBJECTIVE
  Most colorectal cancers (CRCs) arise from adenomatous polyps, but the effects of CRC family history on adenoma risk are not well known. This issue is clinically relevant since several medical societies currently recommend earlier and more rigorous colorectal screening for individuals with a strong family history of CRC.
  
  
  METHODS
  Colonoscopies were performed in 236 first-, second-, and third-degree relatives of 40 index CRC cases from six large kindreds selected from a large population database. The kindreds were selected for significantly greater risk of CRCs compared with the overall population. Known hereditary colon cancer syndromes were clinically and genetically excluded.
  
  
  RESULTS
  Thirty-seven percent of relatives were found to have adenomas on colonoscopy. The average age of diagnosis for colon cancer was 63 yr and advanced adenomas 56 yr. Independent predictors of adenomatous polyps in the relatives were advancing age (P < 0.0001), male gender (P < 0.001), and greater degree of relation to CRC cases (P < 0.01). There was no significant predilection of colorectal tumors for the right or left colon. A higher degree of relationship to CRC cases was a significant predictor of having simple and advanced adenomas, but not hyperplastic polyps after adjustment for age and gender.
  
  
  CONCLUSIONS
  These data support the current recommendations for colonoscopy starting before the age of 50 yr in individuals with a strong family history of CRC.
authors.affiliation: Huntsman Cancer Institute, Salt Lake City, Utah 84112-5550, USA.
authors.forename: Deborah W
authors.initials: DW
authors.lastname: Neklason
authors.forename: Brett L
authors.initials: BL
authors.lastname: Thorpe
authors.forename: Angel
authors.initials: A
authors.lastname: Ferrandez
authors.forename: Anil
authors.initials: A
authors.lastname: Tumbapura
authors.forename: Kenneth
authors.initials: K
authors.lastname: Boucher
authors.forename: Gilda
authors.initials: G
authors.lastname: Garibotti
authors.forename: Richard A
authors.initials: RA
authors.lastname: Kerber
authors.forename: Cindy H
authors.initials: CH
authors.lastname: Solomon
authors.forename: Wade S
authors.initials: WS
authors.lastname: Samowitz
authors.forename: John C
authors.initials: JC
authors.lastname: Fang
authors.forename: Geraldine P
authors.initials: GP
authors.lastname: Mineau
authors.forename: Mark F
authors.initials: MF
authors.lastname: Leppert
authors.forename: Randall W
authors.initials: RW
authors.lastname: Burt
authors.forename: Scott K
authors.initials: SK
authors.lastname: Kuwada
mesh_terms: D000236:Adenoma / Q000453:epidemiology / Q000235:genetics* / Q000473:pathology; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000453:epidemiology / Q000235:genetics* / Q000473:pathology; D005190:Family; D005260:Female; D005500:Follow-Up Studies; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012189:Retrospective Studies; D012307:Risk Factors; D017678:Sex Distribution; D014481:United States / Q000453:epidemiology