Barium enema: detection of colonic lesions in a community population

The purposes of this study were to assess the prevalence of colonic lesions detected at barium enema in a community practice, to compare the findings at barium enema between patients who are asymptomatic and have no known risk factors for colorectal cancer (screening group) and patients who have symptoms of colonic disease or have known risk factors, and to determine if a questionnaire about symptoms and risk factors is an appropriate screening tool.

A self-administered questionnaire about colorectal symptoms and risk factors was given to 1779 patients scheduled for barium enema examination. On the basis of their responses, patients were divided into three groups: screening group (asymptomatic, without risk factors), symptomatic, and asymptomatic with risk factors. Each patient underwent a fluoroscopic barium enema. We then compared the results (number, histologic type, size of lesion(s), location in the colon, and Patient's age) and risk factors among the three groups.

At least one lesion within the colorectum was found in 166 (9%) of 1779 patients at combined proctosigmoidoscopy and barium enema. The prevalence of lesions in the 111 patients with at least one lesion above the rectum at barium enema was 4% (32 of 738) for the screening group, 8% (38 of 476) for asymptomatic patients with risk factors, and 7% (41 of 565) for symptomatic patients (p = .015 when comparing the prevalence in the screening group with the prevalences in the other two groups). Twenty-nine percent of all colonic lesions were found in the screening group. Among the asymptomatic patients, risk factors that included a history of colorectal polyps and advanced age were associated with a significantly higher prevalence of colonic polyps found at barium enema. In the symptomatic group, if patients with histories of polyps were excluded, we were unable to identify other risk factors that led to a significantly higher prevalence of polyps.

Asymptomatic patients without known risk factors have a significantly lower prevalence of colonic polyps than either symptomatic patients or patients with risk factors alone. Despite this lower prevalence, 29% of all lesions in our series were in the screening group. Assessment of risk factors through a patient questionnaire was not helpful in identifying a group of patients with a higher prevalence of lesions--except for a history of polyps. Management decisions based on a patient questionnaire should be approached with caution. When low-risk patients are denied screening examinations, a significant number of lesions will be missed.