Metachronous neoplasia and local recurrence after colorectal endoscopic submucosal dissection

Several reports discussed colonoscopic surveillance after polypectomy and endoscopic mucosal resection (EMR) for colorectal polyps, but only a few reports focused on prognostic analyses, and none involved metachronous neoplasia after colorectal endoscopic submucosal dissection (ESD). We conducted the present study to assess the risk of adenoma recurrence requiring endoscopic treatment, and to establish appropriate post-ESD colonoscopic surveillance. We enrolled 116 patients who had undergone colorectal ESD at Okayama University Hospital between February 2008 and July 2014 and had been followed-up >12 months. We retrospectively analyzed clinicopathological features of 101 lesions from 101 patients. Metachronous adenomas were detected in 21 cases (20.8%). We divided the patients into 2 groups according to the occurrence of metachronous adenomas. Our comparison of clinicopathological characteristics between these groups showed that in the metachronous adenomas group the number of synchronous adenomas at index colonoscopy was high and the rate of laterally spreading tumor-nongranular (LST-NG) was higher. A multivariate analysis indicated that the number of synchronous adenomas was significantly associated with metachronous adenomas (HR: 2.54, 95%CI: 1.04-6.52, p<0.05). The colonoscopic surveillance planning after colorectal ESD should be more meticulous for patients with more synchronous adenomas.