BACKGROUND AND AIMS The incidence of early colorectal cancer (ECC) has been increasing. The aim of this study was to evaluate the clinical outcome and prognosis of ECC treated by endoscopic mucosal resection (EMR).

METHODS A total of 129 ECC patients who were initially treated by EMR between April 2005 and August 2007 were enrolled. Clinicopathological characteristics and prognoses were evaluated retrospectively.

RESULTS En bloc resection was performed in 85% of ECC patients, and piecemeal resection was performed in 15% of patients. Clear lateral and deep margins were achieved in 86% of cases. Of the 129 patients, 64 were found to have intramucosal cancer and 65 had submucosal cancer. Clinical characteristics were not different between patients with intramucosal cancer and submucosal cancer; however, poor differentiation and the absence of background adenoma showed significant association with submucosal cancer. Seven patients with submucosal cancer underwent subsequent surgical resection; five had lymphovascular invasion or a positive resection margin, one had perforation, and one patient requested surgical resection. Of these seven patients, one had residual cancer and two had lymph node metastasis. All patients with intramucosal cancer had no recurrence during the follow-up period. Seven patients with submucosal cancer showed adverse outcomes within 3 years, such as residual/recurrence of primary cancer or lymph node metastasis; five showed lymphovascular invasion or a positive deep margin, and two had no histological risk factors.

CONCLUSIONS Our results suggest that intramucosal cancer shows good prognosis, and a cure could be expected after EMR; however, adverse outcomes can occur in submucosal cancer. Therefore, meticulous endoscopic follow up is needed in patients with submucosal cancer for at least 3 years after EMR.