Is preoperative colonoscopy necessary in carcinoma of the colon and rectum?

The incidence of synchronous polyps of the colon has been shown to be 25 to 40 per cent and the incidence of synchronous carcinomas to be two to eight per cent. Because of this, many surgical groups now advocate routine preoperative colonoscopy on all patients with colon carcinoma. The possibility of spreading and implanting tumor cells with the colonoscope has prompted the authors to purposely avoid preoperative colonoscopy and then clear the colon of any missed lesions with an early postoperative colonoscopy. This study is a retrospective review of 104 patients who have undergone a partial colectomy for colon and rectal carcinoma followed by a postoperative colonoscopy between June 1982 and June 1986. The purpose is to determine the adequacy of intraoperative palpation to detect synchronous neoplasms, and to further define the role of perioperative colonoscopy. The results of 34 per cent synchronous polyps and 5.8 per cent synchronous carcinomas parallels previous studies. The six patients with synchronous carcinomas were discovered by intraoperative palpation and the operation was modified in four of the six patients. Postoperative colonoscopy revealed polyps in 20 per cent of the patients, but all of these were amenable to snare polypectomy or electrocoagulation. No carcinomas were overlooked by palpation. It is our conclusion that intraoperative palpation is adequate for detection of synchronous carcinomas and therefore the risk and expense of preoperative colonoscopy can be avoided. Early postoperative colonoscopy, however, is imperative to clear the colon of small polyps which have the potential to progress to carcinoma.