Value of a risk questionnaire in screening for colorectal neoplasm.

The value of a postal questionnaire and of Hemoccult II (Smith Klein Diagnostic Inc., Sunnyvale, California, USA) testing in screening for colorectal neoplasms was compared. In the questionnaire, the subjects were asked about previous treatment for colorectal neoplasm and rectal bleeding during the previous 6 months, specified as to type. All participants were asked to perform Hemoccult II blood testing over 3 days. Of 13,759 randomly selected subjects 9040 (66 per cent) performed the test and returned the questionnaire. Three hundred and fifty-four subjects with a positive Hemoccult II test and/or a proven previous colorectal neoplasm had a full assessment including double-contrast enema and rectosigmoidoscopy to 60 cm. Eighteen carcinomas and 61 adenomas were thus diagnosed. The population was followed for from 20 to 29 months, during which time rescreening was undertaken. An additional 34 subjects with carcinomas and 90 with adenomas were identified during this period. A significant correlation between the presence of a colorectal neoplasm and a previous history of colorectal neoplasm, a positive Hemoccult II and a previous history of bright red bleeding but not dark bleeding was found. The possibility of diagnosing a neoplasm was two, four and 19 times higher in a subject with a previous history of bleeding, a history of colorectal neoplasm, or a positive Hemoccult II respectively. Screening by faecal occult blood testing, therefore, at the moment seems to be the best and only practicable method.