The Application of Underwater Endoscopic Mucosal Resection for Nonampullary Duodenal Adenomas

We read with great interest the study written by Yamasaki et al.1Yamasaki Y. et al.Clin Gastroenterol Hepatol. 2022; 20: 1010-1018.e3Abstract Full Text Full Text PDF PubMed Scopus (9) Google Scholar The authors reported the efficacy and safety of underwater endoscopic mucosal resection (UEMR) for nonampullary duodenal adenomas. With more and more research on UEMR in recent years, their results are important for clinical practice. However, we do have some comments.First, this is a single-arm trial of UEMR, meaning that comparisons between UEMR and conventional endoscopic mucosal resection (CEMR) were not made. CEMR is one of the routine endoscopic treatments for such lesions.2Ochiai Y. et al.Digestion. 2019; 99: 21-26Crossref PubMed Scopus (20) Google Scholar The direct comparison of these 2 techniques will help determine the more appropriate technique for clinical use. In fact, recently published retrospective studies did not find significant differences between these 2 techniques in terms of recurrence rate indicating likely similar effectiveness in improving long-term outcomes.3Hirasawa K. et al.Scand J Gastroenterol. 2021; 56: 342-350Crossref PubMed Scopus (8) Google Scholar, 4Furukawa M. et al.Clin Endosc. 2021; 54: 371-378Crossref PubMed Scopus (10) Google Scholar, 5Okimoto K. et al.Gastrointest Endosc. 2021; (Epub ahead of print)https://doi.org/10.1016/j.gie.2021.07.011Abstract Full Text Full Text PDF Scopus (9) Google Scholar, 6Toya Y. et al.J Gastroenterol Hepatol. 2021; (Epub ahead of print)https://doi.org/10.1111/jgh.15638Crossref Scopus (4) Google Scholar Whether these results can be replicated in prospective controlled studies is still unclear.Second, the authors found that UEMR showed different en bloc resection rates and R0 resection rates in subgroup analysis with lesion size <10 mm and ≥10 mm, but there was no significant difference in nonrecurrence rates between the 2 subgroups. Considering that only 4 recurrences were eventually found in the study, the lack of difference between the 2 subgroups may be caused by insufficient sample size to detect a difference. Piecemeal resection increases the risk of recurrence,1Yamasaki Y. et al.Clin Gastroenterol Hepatol. 2022; 20: 1010-1018.e3Abstract Full Text Full Text PDF PubMed Scopus (9) Google Scholar,3Hirasawa K. et al.Scand J Gastroenterol. 2021; 56: 342-350Crossref PubMed Scopus (8) Google Scholar,4Furukawa M. et al.Clin Endosc. 2021; 54: 371-378Crossref PubMed Scopus (10) Google Scholar therefore complete resection of the lesion is particularly important for duodenal lesions. A recent study suggested that complete resection rates were similar with endoscopic submucosal dissection, CEMR, and UEMR when the lesion size was ≤10 mm, but endoscopic submucosal dissection had a significant advantage when the lesion size was between 11 and 20 mm.3Hirasawa K. et al.Scand J Gastroenterol. 2021; 56: 342-350Crossref PubMed Scopus (8) Google Scholar UEMR also has shorter resection time and total procedure time for duodenal lesions ≤10 mm.4Furukawa M. et al.Clin Endosc. 2021; 54: 371-378Crossref PubMed Scopus (10) Google Scholar Collectively, these results suggest that only lesions ≤10 mm may be best suited for UEMR, although prospective controlled studies are still needed for verification.In conclusion, before UEMR becomes one of the standard treatment options for duodenal adenomas, the advantages and scope of UEMR need to be further explored in future prospective studies. We read with great interest the study written by Yamasaki et al.1Yamasaki Y. et al.Clin Gastroenterol Hepatol. 2022; 20: 1010-1018.e3Abstract Full Text Full Text PDF PubMed Scopus (9) Google Scholar The authors reported the efficacy and safety of underwater endoscopic mucosal resection (UEMR) for nonampullary duodenal adenomas. With more and more research on UEMR in recent years, their results are important for clinical practice. However, we do have some comments. First, this is a single-arm trial of UEMR, meaning that comparisons between UEMR and conventional endoscopic mucosal resection (CEMR) were not made. CEMR is one of the routine endoscopic treatments for such lesions.2Ochiai Y. et al.Digestion. 2019; 99: 21-26Crossref PubMed Scopus (20) Google Scholar The direct comparison of these 2 techniques will help determine the more appropriate technique for clinical use. In fact, recently published retrospective studies did not find significant differences between these 2 techniques in terms of recurrence rate indicating likely similar effectiveness in improving long-term outcomes.3Hirasawa K. et al.Scand J Gastroenterol. 2021; 56: 342-350Crossref PubMed Scopus (8) Google Scholar, 4Furukawa M. et al.Clin Endosc. 2021; 54: 371-378Crossref PubMed Scopus (10) Google Scholar, 5Okimoto K. et al.Gastrointest Endosc. 2021; (Epub ahead of print)https://doi.org/10.1016/j.gie.2021.07.011Abstract Full Text Full Text PDF Scopus (9) Google Scholar, 6Toya Y. et al.J Gastroenterol Hepatol. 2021; (Epub ahead of print)https://doi.org/10.1111/jgh.15638Crossref Scopus (4) Google Scholar Whether these results can be replicated in prospective controlled studies is still unclear. Second, the authors found that UEMR showed different en bloc resection rates and R0 resection rates in subgroup analysis with lesion size <10 mm and ≥10 mm, but there was no significant difference in nonrecurrence rates between the 2 subgroups. Considering that only 4 recurrences were eventually found in the study, the lack of difference between the 2 subgroups may be caused by insufficient sample size to detect a difference. Piecemeal resection increases the risk of recurrence,1Yamasaki Y. et al.Clin Gastroenterol Hepatol. 2022; 20: 1010-1018.e3Abstract Full Text Full Text PDF PubMed Scopus (9) Google Scholar,3Hirasawa K. et al.Scand J Gastroenterol. 2021; 56: 342-350Crossref PubMed Scopus (8) Google Scholar,4Furukawa M. et al.Clin Endosc. 2021; 54: 371-378Crossref PubMed Scopus (10) Google Scholar therefore complete resection of the lesion is particularly important for duodenal lesions. A recent study suggested that complete resection rates were similar with endoscopic submucosal dissection, CEMR, and UEMR when the lesion size was ≤10 mm, but endoscopic submucosal dissection had a significant advantage when the lesion size was between 11 and 20 mm.3Hirasawa K. et al.Scand J Gastroenterol. 2021; 56: 342-350Crossref PubMed Scopus (8) Google Scholar UEMR also has shorter resection time and total procedure time for duodenal lesions ≤10 mm.4Furukawa M. et al.Clin Endosc. 2021; 54: 371-378Crossref PubMed Scopus (10) Google Scholar Collectively, these results suggest that only lesions ≤10 mm may be best suited for UEMR, although prospective controlled studies are still needed for verification. In conclusion, before UEMR becomes one of the standard treatment options for duodenal adenomas, the advantages and scope of UEMR need to be further explored in future prospective studies. Nonrecurrence Rate of Underwater EMR for ≤20-mm Nonampullary Duodenal Adenomas: A Multicenter Prospective Study (D-UEMR Study)Clinical Gastroenterology and HepatologyVol. 20Issue 5PreviewEndoscopic resection of nonampullary duodenal adenoma is often challenging, and its technique has not yet been standardized. To overcome the practical difficulty of conventional endoscopic mucosal resection, underwater endoscopic mucosal resection (UEMR) was recently developed; therefore, we investigated the effectiveness and safety of UEMR for nonampullary duodenal adenoma. Full-Text PDF ReplyClinical Gastroenterology and HepatologyVol. 20Issue 8PreviewWe thank Lv et al1 for their interest and comments in our study. Underwater endoscopic mucosal resection (UEMR) is recently getting attention for its efficacy and safety for treatment of superficial nonampullary duodenal epithelial tumor (SNADET). Usefulness of UEMR for SNADET had been reported in several reports; however, previous studies had small sample size without evaluation of clinically relevant end points.2,3 Thus, we conducted a multicenter prospective study to evaluate the nonrecurrence rate of UEMR for SNADET using careful follow-up biopsy. Full-Text PDF