Colonic adenoma risk in familial colorectal cancer--a study of six extended kindreds.
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.
Neklason
Deborah W
DW
Huntsman Cancer Institute, Salt Lake City, Utah 84112-5550, USA.
Thorpe
Brett L
BL
Ferrandez
Angel
A
Tumbapura
Anil
A
Boucher
Kenneth
K
Garibotti
Gilda
G
Kerber
Richard A
RA
Solomon
Cindy H
CH
Samowitz
Wade S
WS
Fang
John C
JC
Mineau
Geraldine P
GP
Leppert
Mark F
MF
Burt
Randall W
RW
Kuwada
Scott K
SK
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