The application of underwater endoscopic mucosal resection for superficial duodenal tumors

We read with great interest the study of Kato et al. [1], in which they reported the effectiveness and safety of endoscopic resection for duodenal adenomas. With more and more research on duodenal adenomas in recent years, their results are important for clinical practice; however, we do have some comments.

First, this was a multicenter retrospective study conducted at 18 centers in Japan from January 2008 to December 2018, meaning that tumor resections in the study were performed by different endoscopists and the study did not account for how to reduce this effect. Although, in the only study conducted on colorectal adenomas, the effectiveness and safety of tumor resection were not stratified by the technical proficiency of the operator [2], it is unclear, because of the bending lumen and extremely thin muscle layer in the duodenum, whether these results can be replicated in duodenal adenomas.

Second, the main inclusion criterion of this study was superficial duodenal epithelial tumors unrelated to familial adenomatous polyposis syndrome, meaning that it included both non-ampullary and ampullary duodenal epithelial tumors. It would be useful to perform a subgroup analysis for the different adenoma locations as the anatomy of different portions of the duodenum will affect the maneuverability of the endoscope. For instance, the pyloric ring may pose an obstacle to snaring in the first portion of the duodenum, and lesions frequently extend over multiple folds in the second portion, making it challenging to achieve en bloc and complete resection [3]. Previous studies have focused on non-ampullary duodenal tumors, so it is unclear whether the location of the adenoma will impact the efficacy of underwater endoscopic mucosal resection (UEMR).

In conclusion, further research is needed to determine the parameters that influence the effectiveness and safety of UEMR before it becomes one of the conventional treatment choices for duodenal adenomas.

Publication History

Article published online:
28 June 2023

• References

• 1 Kato M, Takeuchi Y, Hoteya S. et al. Outcomes of endoscopic resection for superficial duodenal tumors: 10 years’ experience in 18 Japanese high volume centers. Endoscopy 2022; 54: 663-670
• 2 Yamashina T, Uedo N, Akasaka T. et al. Comparison of underwater vs conventional endoscopic mucosal resection of intermediate-size colorectal polyps. Gastroenterology 2019; 157: 451-461.e2
• 3 Matsumoto S, Miyatani H, Yoshida Y. Future directions of duodenal endoscopic submucosal dissection. World J Gastrointest Endosc 2015; 7: 389