How to approach endoscopic mucosal resection (EMR)

Colorectal cancer (CRC) is the second leading cause of death from cancer in the UK. Sporadic CRC evolves from premalignant lesions of the colorectum, through a cumulative effect of acquired genetic and epigenetic alterations, typically over the course of several years. Endoscopic polypectomy of these at-risk lesions can prevent the development of CRC. The paucity of lymphatic vessels above the muscularis mucosae enables curative endoscopic mucosal resection (EMR) of even very extensive lesions that are limited to the mucosa.1 2\n\nThis review is aimed at endoscopy trainees, consultants and allied healthcare professionals and describes the place of EMR in therapeutic colonoscopy, clarifying its capabilities and limits, as well as describing newer methods and adjuncts to EMR designed to prevent and treat recurrence.\n\nEMR is a well-established therapeutic technique which can be performed as an outpatient, day-case procedure and has emerged as a safe, efficient and cost-effective alternative to surgery for suitable non-invasive lesions.\n\nThe use of fluid injection to facilitate polypectomy was first described in 1955 and by the 1990s was popularised by Japanese endoscopists and was termed EMR. Injection solutions are used to create a submucosal cushion, separating the colonic lesion from the underlying muscle layer to allow complete resection of the lesion and to prevent full thickness perforation and thermal injury to the colonic wall.\n\nThe vast majority of colorectal polyps are small, 10 mm or less in size. Most of these can be managed using standard snare polypectomy technique.3 EMR is considered the procedure of choice for more difficult polyps, including those greater than 20 mm in size, where submucosal invasion is not suspected and where location poses challenges, such as the involvement of haustral folds or within areas of diverticulosis. Although epidemiological data are lacking, approximately 10%–15% of polyps can be categorised as difficult. …