Is preoperative colonoscopy in carcinoma a realistic and valuable proposition?

Colonoscopy was performed preoperatively in 100 consecutive patients as a prospective study to establish the feasibility of the procedure and its value, which was considered "adequate" when the colon remaining after surgical resection had also been examined preoperatively. Colonoscopy was adequate in 35 of 46 patients (76%) with malignant tumour located in the cecum and ascending and transverse colon, but in only 15 of 54 patients (28%) who had a tumour in the left colon or rectum. Synchronous malignant tumours were present in 2 patients, and 54 additional adenomas were discovered in 29 patients. These adenomas could be removed endoscopically in 13 patients and were included in the standard resection in 12. Extension of the planned operation was necessary in only four patients with synchronous adenomas. Routine preoperative colonoscopy to assess the presence of synchronous colonic tumours is more likely to be adequate in proximal or right-sided large-bowel tumours than in left-sided tumours because of the annular configuration of the latter. Because of the high rate (46%) of synchronous adenomas in adequate examinations, inadequate preoperative colonoscopy should be complemented by a repeat examination 3 to 6 months postoperatively in every patient with a malignant tumour of the large bowel.