Colonoscopic screening of first-degree relatives of patients with large adenomas: increased risk of colorectal tumors.

International audience; Background & Aims: 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 non-University Hospitals. A colonoscopy was offered to first-degree relatives of 306 index cases with adenomas ≥ 10 mm, if they were alive, aged 40-75 and could be contacted by the index case. Among 674 relatives meeting th…