Incidence and recurrence rates of colorectal adenomas in first-degree asymptomatic relatives of patients with colon cancer

Subjects with one first-degree relative affected with colorectal cancer are considered to be at increased risk of colorectal adenomas. We compared the recurrence and incidence rates of colorectal adenomas among subjects with one first-degree relative with colorectal cancer and those without family history. A series of consecutive asymptomatic subjects successfully underwent a colonoscopy, were found to have either normal results or at least one adenoma, provided a detailed family history, and were offered a second colonoscopy 3 yr later; 190 out of 436 subjects accepted, 134/172 with one or more adenomas and 56/264 with no abnormalities at the initial examination. A first-degree family history was reported by 43/134 and 26/56, respectively. By multivariate analysis, the presence of adenomas at follow-up examination was significantly associated with a positive family history of colorectal cancer in both subgroups, those with a previously resected adenoma (odds ratio = 2.23, 95% CI = 1.04–4.79) and those without (odds ratio = 8.95, CI = 1.29–62.22). A history of one first-degree relative with colorectal cancer is associated with a significant increase in 3-yr cumulative incidence and recurrence rates of adenomas.