Colonoscopic screening in first-degree relatives of patients with 'sporadic' colorectal cancer: a case-control study. The Association Nationale des Gastroentérologues des Hôpitaux and Registre Bourguignon des Cancers Digestifs (INSERM CRI 9505)
OBJECTIVE
A screening policy has not been well defined in first-degree relatives of patients with sporadic colorectal cancer. This study estimated the risk of colorectal adenoma in a cohort of individuals with only 1 affected first-degree relative.


METHODS
A total of 476 first-degree relatives (age, 40-74 years) of 195 patients with sporadic colorectal cancer were offered a colonoscopy. Each examined relative was matched with 2 controls for age, sex, symptoms, and center. The prevalence of colorectal adenomas was compared using a multiple logistic regression analysis.


RESULTS
In 185 relatives, odds ratios were 1.5 (95% confidence interval [CI], 1.0-2.4) for adenomas, 2.5 for large adenomas (95% CI, 1.1-5.4), 1.2 for small adenomas (95% CI, 0.7-1.9), and 2.6 (95% CI, 1.3-5.1) for high-risk adenomas (> or = 1 cm in size and/or with a villous component). The prevalence of high-risk adenomas in relatives was higher when the index patient was younger than 65 years, was male, and had distal rather than proximal cancer.


CONCLUSIONS
Subjects with only 1 affected first-degree relative are at increased risk for developing large adenomas.
Pariente
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A
Centre Hospitalier, Pau, France.
Milan
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C
Lafon
J
J
Faivre
J
J
D000236:Adenoma / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics*; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012306:Risk