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. 2025 Jun 27;17(6):103635.
doi: 10.4240/wjgs.v17.i6.103635.

Underwater vs conventional endoscopic mucosal resection for nonpedunculated colorectal neoplasms: A randomized controlled trial

Quang D Le  1 , Nhan Q Le  2 , Duc T Quach  3
Affiliations

Underwater vs conventional endoscopic mucosal resection for nonpedunculated colorectal neoplasms: A randomized controlled trial

Quang D Le et al. World J Gastrointest Surg. .

Abstract

Background: Underwater endoscopic mucosal resection (UEMR) has been shown to be a good treatment option for the management of nonpedunculated polyps ≥ 10 mm since its introduction. However, there is a paucity of randomized controlled trials (RCTs) in Asia.

Aim: To compare the efficacy and safety of UEMR with those of conventional EMR (CEMR) in treating nonpedunculated colorectal lesions.

Methods: We carried out this RCT at a tertiary hospital from October 2022 to July 2024. Patients with nonpedunculated colorectal neoplasms ranging from 10 mm to 30 mm in size were randomly assigned to either the UEMR or CEMR group. The primary outcome was the curative resection (R0) rate. The secondary outcomes included en bloc resection, procedure time, adverse events, and the number of clips used for defect closure.

Results: A total of 260 patients with 260 lesions (130 in each UEMR and CEMR group) were recruited. The median age was 58 (27-85) years, the male/female ratio was 1.74, and the median lesion size was 20 (10-30 mm) mm. Compared with CEMR, UEMR was associated with a significantly greater curative resection (R0) rate (98.4% vs 90.3%; P = 0.007), greater en bloc resection rate (100% vs 94.6%; P = 0.014), shorter procedure time (65 vs 185 seconds; P < 0.001), lower rate of bleeding complications (1.5% vs 10%; P = 0.003), and fewer clips used (2 vs 3; P < 0.001). No perforations were observed in either group.

Conclusion: Compared with CEMR, UEMR has a higher R0 rate, greater en bloc resection rate, shorter procedure time, fewer bleeding complications, and clips used in the management of nonpedunculated colorectal neoplasms.

Keywords: Conventional endoscopic mucosal resection; Curative resection; En bloc resection; Nonpedunculated colorectal neoplasms; Underwater endoscopic mucosal resection.

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Conflict of interest statement

Conflict-of-interest statement: The authors have no conflicts of interest to declare.

Figures

Figure 1
Figure 1
Study flow chart. CEMR: Conventional endoscopic mucosal resection; ITT: Intention-to-treat; PP: Per protocol; UEMR: Underwater endoscopic mucosal resection.
See this image and copyright information in PMC

References

    1. Sung H, Ferlay J, Siegel RL, Laversanne M, Soerjomataram I, Jemal A, Bray F. Global Cancer Statistics 2020: GLOBOCAN Estimates of Incidence and Mortality Worldwide for 36 Cancers in 185 Countries. CA Cancer J Clin. 2021;71:209–249. - PubMed
    1. Burgess NG, Hourigan LF, Zanati SA, Brown GJ, Singh R, Williams SJ, Raftopoulos SC, Ormonde D, Moss A, Byth K, Mahajan H, McLeod D, Bourke MJ. Risk Stratification for Covert Invasive Cancer Among Patients Referred for Colonic Endoscopic Mucosal Resection: A Large Multicenter Cohort. Gastroenterology. 2017;153:732–742.e1. - PubMed
    1. Nusko G, Mansmann U, Partzsch U, Altendorf-Hofmann A, Groitl H, Wittekind C, Ell C, Hahn EG. Invasive carcinoma in colorectal adenomas: multivariate analysis of patient and adenoma characteristics. Endoscopy. 1997;29:626–631. - PubMed
    1. Winawer SJ, Zauber AG, Ho MN, O'Brien MJ, Gottlieb LS, Sternberg SS, Waye JD, Schapiro M, Bond JH, Panish JF. Prevention of colorectal cancer by colonoscopic polypectomy. The National Polyp Study Workgroup. N Engl J Med. 1993;329:1977–1981. - PubMed
    1. Kaltenbach T, Anderson JC, Burke CA, Dominitz JA, Gupta S, Lieberman D, Robertson DJ, Shaukat A, Syngal S, Rex DK. Endoscopic Removal of Colorectal Lesions-Recommendations by the US Multi-Society Task Force on Colorectal Cancer. Gastroenterology. 2020;158:1095–1129. - PubMed