Editor’s Choice: Underwater versus conventional EMR of large nonpedunculated colorectal lesions: a multicenter randomized controlled trial

GIE Associate Editor Thiruvengadam Muniraj, MD, highlights this article from the May issue: “Underwater versus conventional EMR of large nonpedunculated colorectal lesions: a multicenter randomized controlled trial” by Joaquín Rodríguez Sánchez, MD, PhD, et al.


This study is valuable because it explores alternate options for endoscopic submucosal dissection (ESD). This is one of the very few randomized controlled trials on this topic.

Incomplete polypectomy on EMR is a significant cause of interval colorectal cancer. Despite the low recurrence rates achieved with ESD, the widespread implementation of this technique in the United States remains slow because of several reasons.

EMR continues to be the most commonly used technique for large, nonpedunculated colorectal lesions (LNPCLs). Several retrospective studies have shown underwater EMR (UEMR) has high en bloc resection rates with lower recurrences.

Joaquín Rodríguez Sánchez et al conducted a multicenter randomized control trial in Spain to compare the efficacy and safety of UEMR versus conventional EMR (CEMR) for the treatment LNPCLs (≥20 mm). The results of their study are promising, indicating that UEMR is a valid alternative to CEMR for LNPCLs because of higher en bloc and R0 resection rates.

As noted in this study, many physicians find UEMR to be faster and easier. Overall, the study highlights the importance of exploring alternative treatment options for LNPCLs. These findings could lead to changes in clinical practice, with UEMR becoming the first-line treatment option for lesions larger than 20 mm.


Underwater EMR technique. A, Homogeneous granular–laterally spreading tumor with a size of 30 mm located in the cecum close to the appendicular orifice. B, Classified as JNET2A (per the Japan NBI Expert Team classification) with a blue-light imaging chromoendoscopy system (Fujifilm VP-7000; FUJIFILM Medical Systems). C, Lesion in immersion before attempting “underwater” EMR. D, Underwater piecemeal EMR using a 15-mm braided snare. E, Scar in immersion. F, Scar without water immersion classified as Sydney 0.

Read the full article online.

The information presented in Endoscopedia reflects the opinions of the authors and does not represent the position of the American Society for Gastrointestinal Endoscopy (ASGE). ASGE expressly disclaims any warranties or guarantees, expressed or implied, and is not liable for damages of any kind in connection with the material, information, or procedures set forth.

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