Double-contrast Barium Enema versus Colonoscopy in the Diagnosis of Neoplastic Disorders: Aspects of Decision-making in General Practice

A total of 190 patients, referred by general practitioners fora double-contrast barium enema, were subsequently examined withcolonoscopy. With colonoscopy and histology as the referencestandard, sensitivity, specificity, positive and negative predictivevalues, and accuracy for the radiological detection of cancerand polyps were calculated. No cancer was overlooked by theradiological examination, but there were four false positives.The overall sensitivity for polyps was 70%, increasing to 81%for polyps 10 mm. The predictive value was 93–97% forthe exclusion of polyps. The caecum was reached in 187 patientsby double-contrast barium enema (98%) and in 164 patients (86%)by colonoscopy. Lesions in four of 12 patients who had radiologicalchanges were undetected at the first colonoscopy, but a repeatexamination showed polyps 10 mm in size. Although colonoscopyis a more sensitive technique for the detection of small mucosallesions, the general practitioners may, in the vast majorityof patients, rely on a negative result for polyps and cancerobtained by the double-contrast barium enema. The latter islinked with a number of false-positive cases, while colonoscopyis associated with technical difficulties; both techniques maylead to repeated examinations, regardless of which was the firstchoice.