Colonoscopy findings in symptomatic patients without X-ray evidence of colonic neoplasms.

Colonoscopy was carried out in 97 patients with persistent large-bowel symptoms in whom double-contrast barium enemas were either normal or showed diverticular disease alone. In 37 the X-ray was normal, but colonoscopy showed 9 polyps and 3 carcinomas. In 60 patients with barium enemas showing diverticular disease alone colonoscopy revealed 13 polyps and 1 carcinoma. Of the 4 carcinomas 1 was Dukes' A, 2 Dukes' B, and 1 Dukes' C. 23 of the 26 patients with a neoplastic lesion at colonoscopy had rectal bleeding, compared with only 40 of the 71 without a lesion. The frequency of neoplasia in those with a normal barium enema was 32%, compared with 23% in those whose X-ray showed diverticular disease. Colonoscopy, rather than double-contrast barium enema, should be the first line of investigation in patients with persistent large-bowel symptoms, especially rectal bleeding.