Clinicopathologic Characteristics of Endoscopically Resected Early Colorectal Cancer

Abstract

Background: Recently, early detection and endoscopic treatment for early colorectal cancer (ECC) has increased due to screening colonoscopy. The aim of this study was to evaluate the clinicopathologic characteristics of ECC diagnosed by endoscopic mucosal resection (EMR). Methods: A total of 2224 adenomatous polyps from 1215 patients were removed by EMR in Seoul National University Hospital from April 2005 to August 2006. A total of 106 polyps from 104 patients were diagnosed pathologically as ECC after EMR. Clinocopathologic features of ECC were analyzed retrospectively. Results: The mean age of the patients was 62 years old (range, 29-91) with a male : female ratio of 3 : 1. The mean size of the ECCs was 1.7 cm (range, 0.6-5); less than 1 cm in 14 (13%) ECCs, 1-2 cm in 55 (52%), 2 cm or more in 37 (35%). Most of ECCs (86%) were located in the left-sided colon and macroscopic appearances were pedunculated (Ip)-type in 33%, semipedunculated (Isp)-type in 26%, sessile (Is)-type in 29% and laterally spreading tumor (LST)-type in 11%, respectively. Sixty-eight (64%) ECCs were mucosal cancer (m-cancer) and 38 (36%) were submucosal cancer (sm-cancer). En bloc and complete resection rate was 82% and 87% for m-cancer, 90% and 71% for sm-cancer, respectively (P = 0.05). In univariate analysis, whereas sessile morphology, multiplicity, poor differentiation, the presence of lymphovascular invasion and the absence of an adenomatous component were significantly associated with sm-cancer (P < 0.01), the size or location of ECC was not associated with submucosal invasion. Lymph node metastasis was found in 2 patients with sm-cancer among the 5 patients who underwent subsequent surgical resection due to unfavorable histology. Twenty lesions (56%, 20/36) diagnosed as adenoma on forcep biopsy before EMR proved to be an adenocarcinoma after EMR. Conclusion: In our study, the incidence of ECC after EMR for colorectal polyp was 4.8%. All polyps observed during colonoscopy should be completely resected for the possibility of malignancy irrespective of size or histology obtained by prior forcep biopsy.