Endoscopic Resection Techniques for Precancerous and Early Cancerous Lesions in the Rectum

Abstract

Today, endoscopy plays a decisive role not only in the detection of colorectal adenomas and carcinomas, but also in the treatment of precancerous lesions, in particular flat adenomas and early carcinomas. In recent years, endoscopic submucosal dissection (ESD) has become increasingly important alongside classic polypectomy and mucosal resection after saline injection using a snare (EMR). Using ESD the lesion is marked, injected submucosally using viscous substances and the mucosa incised and tunneled with a transparent cap and a fine diathermy knife. Particularly in the case of widespread and high-risk lesions ESD enables a quasi-surgical "en bloc" resection almost regardless of size, with a histological R0 resection rate of far over 90% in specialized centers. ESD enables an excellent histopathological evaluation and has a low recurrence risk of 1-3%. Endoscopic full-thickness resection using a dedicated device (FTRD system) represents another addition to the armamentarium. It can be used for circumscribed submucosal, suspicious or scarred changes up to 2cm in the middle and upper rectum. Endoscopic intermuscular dissection (EID) enables histopathological analysis of the complete submucosa beyond the mucosa and upper submucosal layer by including the circular inner muscle layer within the resection specimen. It reduces basal R1 situations and offers a new perspective for T1 carcinomas through curative, organ-preserving endoscopic therapy, especially in the case of deep submucosal infiltration alone, without other risk factors for metastases. Indications, the procedure itself and significance of the various techniques for premalignant and early malignant lesions in the rectum are presented.