The risk of developing colorectal neoplasia is not well established among family members of individuals with large adenomas.
Screening strategies remain under debate in this population.
Dr Vanessa Cottet and colleagues from France quantified the risk of colorectal adenomas and cancers using colonoscopic screening in first-degree relatives of patients with large adenomas.
|The prevalence of cancers was 8% in relatives, and 4% in controls|
The team performed a case-control study in 18 endoscopic units of French nonuniversity hospitals.
A colonoscopy was offered to first-degree relatives of 306 index cases with adenomas of 10 mm if they were alive, aged 40 to 75 years.
Among them, 168 were examined and matched for age, sex, and geographical area with 307 controls.
Controls were randomly selected from 1362 consecutive patients aged 40 to 75 years having undergone a colonoscopy for minor symptoms.
The researchers found the prevalence of large adenomas and cancers was 8% and 4%, in relatives and controls, respectively.
Odds ratios associated with a history of large adenomas in relatives were 2.3 with cancers or large adenomas, 1.2 for small adenomas, and 1.6 for all colorectal neoplasia.
The team found the risk of large adenomas and cancers was higher in relatives of index cases younger than 60 years.
In addition, the research team noted that the risk of large adenomas and cancers was higher when the index case had large distal adenomas.
Dr Cottet's team concluded, "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."