Colonoscopic screening of first-degree relatives of patients with large adenomas: increased risk of colorectal tumors.
OBJECTIVE
The risk of developing colorectal neoplasia is not well established among family members of individuals with large adenomas, and screening strategies remain under debate in this population. This study aimed at quantifying the risk of colorectal adenomas and cancers using colonoscopic screening in first-degree relatives of patients with large adenomas.


METHODS
This case-control study was performed in 18 endoscopic units of French nonuniversity hospitals. A colonoscopy was offered to first-degree relatives of 306 index cases with adenomas > or =10 mm if they were alive, aged 40-75 years, and could be contacted by the index case. Among them, 168 were examined and matched for age, sex, and geographical area with 2 controls (n = 307). Controls were randomly selected from 1362 consecutive patients aged 40-75 years having undergone a colonoscopy for minor symptoms.


RESULTS
The prevalence of large adenomas and cancers was 8.4% and 4.2%, in relatives and controls, respectively. Odds ratios (ORs) associated with a history of large adenomas in relatives were 2.27 (95% confidence interval [CI], 1.01-5.09) for cancers or large adenomas, 1.21 (95% CI, 0.68-2.15) for small adenomas, and 1.56 (95% CI, 0.96-2.53) for all colorectal neoplasia. The risk of large adenomas and cancers was higher in relatives of index cases younger than 60 years (OR, 3.82; 95% CI, 0.92-15.87) and when the index case had large distal adenomas (OR, 3.14; 95% CI, 1.27-7.73).


CONCLUSIONS
First-degree relatives of patients with large adenomas are at increased risk of developing colorectal cancers or large adenomas. This result has implications for screening in this high-risk population.
Cottet
Vanessa
V
INSERM Unité 866, Dijon, France.
Pariente
Alexandre
A
Nalet
Bernard
B
Lafon
Jacques
J
Milan
Chantal
C
Olschwang
Sylviane
S
Bonaiti-Pellié
Catherine
C
Faivre
Jean
J
Bonithon-Kopp
Claire
C
D000236:Adenoma / Q000175:diagnosis* / Q000453:epidemiology / Q000473:pathology; D000328:Adult; D000367:Age Factors; D000368:Aged; D016022:Case-Control Studies; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000453:epidemiology / Q000473:pathology; D005190:Family; D005260:Female; D005602:France / Q000453:epidemiology; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods*; D008875:Middle Aged; D009367:Neoplasm Staging; D016017:Odds Ratio; D011237:Predictive Value of Tests; D015995:Prevalence; D018570:Risk Assessment; D012307:Risk Factors