Preoperative classification of submucosal fibrosis in colorectal laterally spreading tumors by endoscopic ultrasonography

Background and study aims: Although endoscopic submucosal dissection (ESD) is an established therapy for colon neoplasms including laterally spreading tumors (LSTs), its application to advanced fibrotic lesions is very difficult owing to the thin walls of the large intestine. We examined the ability of preoperative endoscopic ultrasonography (EUS) to predict lesion fibrosis in patients undergoing colorectal ESD. Patients and methods: From 2009 to 2013, 58 LSTs were evaluated retrospectively with EUS and treated using colorectal ESD. The degree of submucosal fibrosis was determined during ESD and classified as F0 (no fibrosis), F1 (mild fibrosis), or F2 (severe fibrosis). Results: The sensitivity and specificity of fibrosis prediction by preoperative EUS of all cases were 77.8 % and 57.1 %, respectively. However, there was a high accuracy (97.2 %, 35/36) for only the 36 LSTs with clear and visible images. In one case, EUS diagnosed no fibrosis but significant fibrosis was found during ESD, the result of colon cancer invasion into the submucosa. Conclusions: Preoperative EUS before colorectal ESD successfully predicted the degree of fibrosis in a number of cases.