Copyright ©The Author(s) 2022. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastrointest Endosc. Mar 16, 2022; 14(3): 113-128
Published online Mar 16, 2022. doi: 10.4253/wjge.v14.i3.113
Endoscopic management of difficult laterally spreading tumors in colorectum
Edgar Castillo-Regalado, Hugo Uchima
Edgar Castillo-Regalado, Hugo Uchima, Endoscopy Unit, Department of Gastroenterology, Hospital Universitari Germans Trias i Pujol, Barcelona 08916, Spain
Edgar Castillo-Regalado, Endoscopic Unit, Creu Groga Medical Center, Calella 08370, Spain
Hugo Uchima, Endoscopic Unit, Teknon Medical Center, Barcelona 08022, Spain
Author contributions: Castillo-Regalado E wrote the paper; Uchima H wrote and reviewed the paper.
Conflict-of-interest statement: The authors declare no conflict of interest for this article.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See:
Corresponding author: Hugo Uchima, MD, Consultant Physician-Scientist, Endoscopy Unit, Department of Gastroenterology, Hospital Universitari Germans Trias i Pujol, Carretera de Canyet s/n, Barcelona 08916, Spain.
Received: June 30, 2021
Peer-review started: June 30, 2021
First decision: October 18, 2021
Revised: November 1, 2021
Accepted: February 15, 2022
Article in press: February 15, 2022
Published online: March 16, 2022

Due to the advent of the screening programs for colorectal cancer and the era of quality assurance colonoscopy the number the polyps that can be considered difficult, including large (> 20 mm) laterally spreading tumors (LSTs), has increased in the last decade. All LSTs should be assessed carefully, looking for suspicious areas of submucosal invasion (SMI), such as nodules or depressed areas, describing the morphology according to the Paris classification, the pit pattern, and vascular pattern. The simplest, most appropriate and safest endoscopic treatment with curative intent should be selected. For LST-granular homogeneous type, piecemeal endoscopic mucosal resection should be the first option due to its biological low risk of SMI. LST-nongranular pseudodepressed type has an increased risk of SMI, and en bloc resection should be mandatory. Underwater endoscopic mucosal resection is useful in situations where submucosal injection alters the operative field, e.g., for the resection of scar lesions, with no lifting, adjacent tattoo, incomplete resection attempts, lesions into a colonic diverticulum, in ileocecal valve and lesions with intra-appendicular involvement. Endoscopic full thickness resection is very useful for the treatment of difficult to resect lesions of less than 20 up to 25 mm. Among the indications, we highlight the treatment of polyps with suspected malignancy because the acquired tissue allows an exact histologic risk stratification to assign patients individually to the best treatment and avoid surgery for low-risk lesions. Endoscopic submucosal dissection is the only endoscopic procedure that allows completes en bloc resection regardless of the size of the lesion. It should therefore be indicated in the treatment of lesions with risk of SMI.

Keywords: Colorectal polyps, Laterally spreading tumors, Endoscopic mucosal resection, Underwater endoscopic mucosal resection, Endoscopic full thickness resection, Endoscopic submucosal dissection

Core Tip: The number of detected large laterally spreading tumors has increased in the last decade. Herein, we review the current landscape of different endoscopic techniques that allow us to resect difficult laterally spreading tumors. We also describe strategies in problematic situations such as scarred lesions or difficult areas and how to treat adverse events related to colonoscopy.