The diagnostic criteria for advanced malignant disease of the large bowel are well recognized, but the diagnosis of early cancer and the differential diagnosis of benign polyps, diverticulitis and carcinoma require the closest cooperation of the clinician, the radiologist and the pathologist.
In a previous presentation of this subject, comprising a review1 of 100 cases of cancer of the rectum, 100 cases of cancer of the left colon and 100 cases of cancer of the right colon, it was noted that the chief complaints of the patients could be placed in three groups (table 1):
Rectal bleeding. Over 80 per cent of all patients with malignant disease of the large bowel will have associated rectal bleeding. This is the most significant symptom of cancer of the colon and rectum.
An alteration or change in bowel function. The mildly constipated patient who has been taking an