Validity of self-reported colorectal cancer screening behavior

End points for trials promoting cancer screening are often based on self-re ported screening behavior. This study war designed to evaluate and optimize the reliability of a computer-assisted telephone interview for collecting self-reported colorectal cancer screening behavior. Cases who had received a fecal occult blood test (FOBT), flexible sigmoidoscopy, and/or colonoscop y, and controls who had no record of colorectal screening were identified a mong 40-75-year-old members of the Denver Kaiser Permanente Health Care Pro gram and were contacted by telephone. Sensitivities and specificities of se lf-reported screening were calculated by comparison of subjects' recall wit h Kaiser Permanente records. The questionnaire was revised based upon resul ts of the pilot phase of the study. Using the revised questionnaire, the se nsitivity of self-reported screening was 96.2% for the FOBT, 94.9% for flex ible sigmoidoscopy, 88.7% for colonoscopy, and 96.2% for either endoscopic screening test. The specificity of self-reported screening was 85.9% for th e FOBT, 92.2% for flexible sigmoidoscopy, 96.8% for colonoscopy, and 92.0% for either endoscopic screening test. No marked differences in the accuracy of the self-reports were detected as a function of gender, age, ethnicity, or family history of colorectal cancer of the participants. Self-reports o f colon cancer screening behavior ran be reliably used as end points for in tervention trials when carefully phrased questions are used.