Role of computed tomographic colonoscopy of postoperative surveillance in patient with gastric cancer

AIM： TO examine the diagnostic yield of colorectal neoplasia at computed tomographic colonoscopy （CTC） as well as the feasibility of contrast enhanced CTC in patients with gastric cancer. METHODS： To examine the incidence of colon polyp we selected postoperative 188 gastric cancer patients, which we refer to as the ‘colon polyp survey group’. To examine the feasibility of CTC for early detection of colon cancer or advanced colon adenoma, we selected 47 gastric cancer patients （M：F 29：18, mean age 53.8 years）, which we call the ‘CT colonoscopy group’. All the 47 patients underwent successive CTC and colonoscopy on the same day. RESULTS： Totally 109 colon polyps were observed from 59 out of 188 gastric cancer patients, the inddence rate of colon polyps in gastric cancer patients being 31.4%. The sensitivity of CTC in detecting individuals with at least 1 lesion of any size was 57.1%, the specificity was 72.7%, the positive predictive value was 47.1%, and the negative predictive value was 71.9%. When the cutoff size was decreased to 6 mm, the sensitivity and specificity were 80.0% and 92.9%, respectively, with positive and negative predictive values of 57.1% and 97.5%, respectively. Only one patient was classified as false negative by virtual colonoscopy. CONCLUSION： The diagnostic yield of colorectal polyp was 31.4% in patients with gastric cancer, and contrast enhanced CTC is an acceptable tool for the detection of synchronous colorectal advanced adenoma and postoperative surveillance of gastric cancer patients.