Advanced Tissue Resection in Gastroenterology: Indications, Role, and Outcomes

Endoscopic Mucosal Resection (EMR)

EMR is currently utilized for curative treatment of a wide array of GIT lesions limited to the mucosal layer, whether metaplastic, dysplastic, or even in cases with early mucosal cancer, where the risk of submucosal and lymphatic invasion is minimal.⁴ This makes EMR a versatile and proven therapy, often serving as the first-line treatment for many GIT lesions.

^{Washington University}

Dr. Arvind Rengarajan

EMR has various techniques that could be categorized into suction or non-suction (lift and cut) techniques. In the suction technique, devices like multiband mucosectomy (MBM) are commonly used, especially in nodular Barrett’s dysplasia, forming a pseudopolyp for subsequent resection. The procedure is characterized by its safety, efficacy, and cost-effectiveness, contributing to its widespread adoption in clinical practice. In the lift and cut approach, a submucosal injection is utilized to separate the muscularis propria from the lesion, thereby reducing the risk of perforation. Different solutions, such as normal saline, hypertonic saline, 50% dextrose, or proprietary submucosal injection solutions, are employed for submucosal injection.⁵

The non-suction technique using a snare to resect polyps after injection is more often used in colonic and small intestinal EMR. Resection can be done via thermal energy in the form of cut or coagulation; however, there is rising data on the use of piecemeal cold snare resection for select flat polyps of the colon.⁶ There is also promising data on the role of underwater EMR, a common technique employed for colonic lesions, particularly if the lesion does not lift well with submucosal injection.⁷

Adverse events associated with EMR include bleeding (7%-8%) and perforation (0.9%-2%).^8-9 Adequate submucosal fluid injection is crucial to prevent perforations. However, the main limitation of EMR is the piecemeal nature of resections for lesions larger than 20 mm, leading to compromised histopathologic evaluation for complete excision, especially in cases with superficial submucosal invasion (SMI). This can result in residual or recurrent tissue, reportedly 8% to 20%.¹⁰ Despite this limitation, EMR remains a reliable strategy, and recurrent lesions are generally manageable through repeat sessions. The importance of EMR as a therapeutic modality lies in its role in addressing lesions with favorable characteristics, where the risk of SMI is low.

^{Washington University}

Dr. Ahmad Najdat Bazarbashi

Endoscopic Submucosal Dissection (ESD)

ESD is an evolving technique that can be utilized for submucosal lesions of the GIT, lesions not amenable to EMR due to submucosal fibrosis, when en bloc removal of a lesion is needed for accurate histopathological diagnosis, and when other techniques fail.^11-12

ESD was only recently adopted in the United States, requires specialized training, and usually is a lengthier procedure than EMR.¹³ Compared to EMR, it has higher en bloc resection rates and lower recurrence rates, making it curative for lesions with superficial SMI and favorable histologic features.^4,14 The safety profile of ESD appears favorable, with most of the adverse events managed successfully by endoscopic methods. Major complications include intraoperative and delayed perforation, intraoperative and delayed bleeding, aspiration pneumonia, thromboembolism, and stricture formation in the case of circumferential lesions.¹⁵

Despite being technically challenging, ESD may provide a cost-effective long-term solution by avoiding surgery, reducing the need for additional interventions by minimizing recurrence rates. Given the technical complexity of ESD, particularly the submucosal dissection portion, techniques such as hybrid ESD developed. Hybrid ESD combines snaring with circumferential mucosal incision and partial submucosal dissection. Although it promises shorter procedure times, reduced complication rates like perforation, and similar recurrence rates compared to traditional ESD, studies have shown lower success rates in en bloc resection.^16-17

Both EMR and ESD are considered complementary strategies, and the choice between them should be dictated by lesion characteristics, patient preferences, and local expertise.