Prevalence of any size adenomas and advanced adenomas in 40- to 49-year-old individuals undergoing screening colonoscopy because of a family history of colorectal carcinoma in a first-degree relative

Background: Per current guidelines, patients with a first-degree relative (FDR) with colorectal cancer (CRC) should get screened at least at age 40. Data about the prevalence of adenomas and advanced adenomas (AAs) in these patients are lacking. Objective: To examine the prevalence of adenomas and AAs in 40- to 49-year-old individuals undergoing screening colonoscopy for family history of CRC. Design: Retrospective chart review. Patients: Asymptomatic patients 40 to 49 years of age undergoing their first screening colonoscopy at the University of Michigan during the period 1999 to 2009 because of an FDR with CRC. Main Outcome Measurements: Prevalence of adenomas (any size), AAs, and risk factors associated with adenomas. Results: Among 640 study patients, the prevalence of adenomas (any size) was 15.4% and 3.3% for AAs. Adenoma prevalence was lower if the FDR with CRC was younger than 60 years of age versus an FDR with CRC older than 60 years of age (12.4% vs 19%, P = .034). Male sex (odds ratio 2.6; 95% CI, 1.06-4.4) and advancing age (odds ratio 1.16; 95% CI, 1.03-1.31) were associated with adenomas. Limitations: Limited data on risk factor exposure and insufficient sample size to assess risk factors for AAs. Conclusions: Among 40- to 49-year-old patients undergoing screening colonoscopy because of an FDR with CRC, the prevalence of adenomas and AAs is low. Further research should determine whether these individuals have a higher prevalence of adenomas compared with average-risk individuals.