Reply to Lv and Yang

We thank Drs. Lv and Yang for their comments concerning our article “Outcomes of endoscopic resection for superficial duodenal tumors: 10 years’ experience in 18 Japanese high-volume centers” [1].

In this study, we compared resection outcomes of underwater endoscopic mucosal resection (UEMR) and conventional EMR. The en bloc resection rate (78.6 % vs 86.8 %) was significantly lower with UEMR, whereas there was no significant difference in the R0 resection rate (56.0 % vs 61.2 %). For colorectal neoplasms, a randomized controlled trial comparing outcomes of UEMR and EMR reported that UEMR had a higher R0 resection rate than EMR [2]. In the duodenum, there is controversy about the most appropriate resection method between UEMR and EMR, with some reports suggesting the superiority of UEMR [3] [4] and others suggesting superiority of EMR [5]. Omitting submucosal injection would allow easier snaring by shrinking the target mucosa; however, it would impair the visibility of lesions, particularly those located in areas such as behind Kerckring folds and in the flexural part of the duodenum.

Drs. Lv and Yang pointed out that studying the local recurrence rate in smaller lesions is important for appropriate selection of treatment. In our study, the incidence of delayed adverse events following ESD of lesions smaller than 20 mm was 7.4 %, more than three times the incidence for non-ESD lesions (1.9 %). Considering that an en bloc resection rate of nearly 90 % was achieved with non-ESD, we concluded that ESD is not recommended for this population.

Our study provided real-world data concerning duodenal endoscopic treatment through analysis of more than 3000 cases. However, unavoidable bias due to the retrospective study design and differences in patient background are suspected. Thus, further prospective studies, ideally randomized controlled trials directly comparing each treatment, are required.

Publication History

Article published online:
21 April 2022

• 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 2021; DOI: 10.1055/a-1640-3236.
• 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
• 3 Okimoto K, Maruoka D, Matsumura T. et al. The utility of underwater endoscopic mucosal resection for nonpolypoid superficial nonampullary duodenal epithelial tumors ≤20 mm. Gastrointest Endosc 2021; DOI: 10.1016/j.gie.2021.07.011.
• 4 Furukawa M, Mitoro A, Ozutumi T. et al. Efficacy of underwater endoscopic mucosal resection for superficial non-ampullary duodenal epithelial tumor. Clin Endosc 2021; 54: 371-378
• 5 Kiguchi Y, Kato M, Nakayama A. et al. Feasibility study comparing underwater endoscopic mucosal resection and conventional endoscopic mucosal resection for superficial non-ampullary duodenal epithelial tumor <20 mm. Dig Endosc 2020; 32: 753-760