Carcinoma of the colon and rectum. Tumors missed by radiologic examination in 61 patients.

Radiologic examinations preceding the diagnosis of colorectal carcinomas were retrospectively scrutinized in 708 patients with 731 carcinomas that were radiographically investigated 741 times. Sixty-four lesions were missed 74 times, giving a 90% sensitivity of the radiographic methods used. Of the errors, 82% were perceptive, and 3% were interpretative. Eleven examinations in nine patients revealed no lesions, although the examinations were done within 2 years of the diagnosis of a carcinoma. Missed lesions were more common than expected in the cecum and the ascending colon (P less than 0.001), and 18% of the patients had multiple tumors (expected incidence 3.6%, P less than 0.001). The median delay in diagnosis was 20 months, and patients whose diagnosis was delayed for a long time tended to have more advanced carcinomas at diagnosis. As a lesion was identified either at the initial examination or retrospectively 730 of 741 times, the potential sensitivity of the radiographic methods used was 99%. It is concluded that barium enema is still an excellent method for the detection of colorectal carcinoma provided that perceptive errors can be minimized.