Analysis of Colonic Synchronous Lesions in Colorectal Cancer

Purpose: The aim of this study is to evaluate the incidence of synchronous colonic lesions and to identify the impact of an incomplete preoperative colonoscopy in colorectal cancer patients. Methods: We studied 187 patients with colorectal cancer who received colonoscopic examinations pre or postoperatively in our hospital from January 2000 to March 2002. The pre and postoperative colonoscopic findings were reviewed. Most post-operative colonoscopies were performed 12 months after the operation, but in cases of incomplete pre-operative examination, they were performed at 6 months. We analyzed the incidence of synchronous lesions of the colon and the rectum and then compared the findings for complete and incomplete pre-operative examinations. Results: Complete pre-operative colonoscopic examinations were performed in 152 patients, but in 35 patients, the colonoscopy was performed incompletely. Twenty-two of these 35 patients had obstructive colorectal cancer. In the complete examination group, 23 patients had synchronous lesions preoperatively; 20 cases were benign, and 3 cases were malignant. By postoperative colonoscopic examination, 27 patients had synchronous polyps. In 19 of the 27, the polyps had not been detected preoperatively. The incidence of synchronous lesions in the complete examination group was 27.6% (42/152), and the incidence of synchronous cancer was 2.0% (3/152). In the incomplete examination group, the incidence of synchronous lesions was 37.1% (13/35), and the incidence of malignancy was 2.9% (1/35). The incidence of synchronous lesions in the preoperative incomplete examination group was higher than it was in the complete examination group, but the difference was not statistically significant (P=0.161). Conclusions: In our study, the incidence of synchronous lesions with colorectal cancer patients was 29.4%, and the incidence of malignancy was 2.1%, these are similar to figures in others reports. Patients with an incomplete preoperative entire-colon examinations should have immediate postoperative colonoscopy.