Colonic Neoplasms in Asymptomatic First‐Degree Relatives of Colon Cancer Patients

First‐degree relatives of colon cancer patients are at elevated risk for developing colorectal neoplasms. In order to assess the potential usefulness of screening by colonoscopy in this high‐risk population, we reviewed the records of 48 colonoscopies performed on asymptomatic patients who were self‐ or physician‐referred for colonoscopy because of a history of one or more first‐degree relatives with colon cancer. Twelve (25%) had at least one adenomatous polyp, but no significant atypia was detected. No cancers were detected. One third of the lesions were beyond the reach of a flexible sigmoidoscope. This apparent increase in the prevalence of adenomas was most striking (46%) among men over the age of 50. These preliminary results demonstrate that colonoscopy is effective in detecting and removing adenomatous polyps in a substantial fraction of asymptomatic patients whose sole risk‐factor is being a first‐degree relative of a patient with colon cancer. Further studies in larger populations are warranted to determine the use of colonoscopy in screening these high‐risk individuals.