Endoscopic Mucosal Resection and Endoscopic Piecemeal Mucosal Resection for Colorectal Neoplasia

Abstract

Endoscopic mucosal resection (EMR), including endoscopic piecemeal mucosal resection (EPMR), allows a less invasive treatment option, especially for flat and depressed type (F&D type) colorectal neoplasia, and can provide specimens for histopathological analysis. EMR should be applied for colorectal adenomas, carcinoma in situ, and focally extended submucosal cancers (equivalent to submucosal cancers with less than 1000 μm invasion distance) without lymph node metastasis. To determine the indication of EMR, invasion depth diagnosis is important, with the use of the indigo carmine dye spray method and also high-frequency ultrasound probes (HFUP) or magnifying colonoscopy with the narrow-band imaging system (NBI). If the lesion requires piecemeal resection, especially for larger lesions 21 mm or more in size, intentional EPMR is recommended. Larger-sized high nodules, or a region with the histological estimation of high malignant potential by magnifying colonoscopy, should be resected en bloc, followed by other resection procedures for residual lesion. EMR including EPMR provide a 95% or more success rate and fewer complications for the treatment of F&D type early colorectal neoplasia. As the detection of F&D type tumors increases EMR and EPMR will become a more essential treatment for colorectal neoplasia, including early carcinomas.