Resection depth for small colorectal polyps comparing cold snare polypectomy, hot snare polypectomy and underwater endoscopic mucosal resection

Results of the COLDWATER randomized controlled trial: enhanced performance of underwater cold snare polypectomy for colorectal polyps 5-10 mm, independent of endoscopist experience

Background

The wide range of R0 resection rates (R0RR) and incomplete resection rates (IRR) observed with conventional cold snare polypectomy (CCSP) emphasizes the necessity for technique enhancement. The COLDWATER study aimed to compare underwater cold snare polypectomy (UCSP) to CCSP for 5-10-mm colorectal polyps, focusing on comprehensive histopathological evaluation, efficacy, and safety.

Methods

This was a randomized, single-blind, controlled trial comparing UCSP to CCSP for non-pedunculated colorectal polyps of size 5-10 mm. The primary outcome was to report differences in the muscularis mucosa resection ratio. The secondary outcomes focused on differences in depth of excision, R0-RR, IRR, en bloc resection rate, adverse events, and recurrence rate.

Results

The COLDWATER study found higher muscularis mucosa resection in UCSP (81.72±62.81% vs. CCSP: 72.33±22.33%, P=0.003) with comparable submucosa presence (UCSP: 16.6%, CCSP: 12.5%, P=0.25). UCSP showed better outcomes regarding IRR (3.5% vs. 8.5%, P=0.05) and en bloc resection (98% vs. 93.5%, P=0.04). In CCSP, expert endoscopists achieved higher R0RR than non-experts, while UCSP showed no significant difference in R0RR across endoscopist's experience levels.

Conclusions

UCSP achieves a more extensive excision of the muscularis mucosa compared to CCSP, even though it does not attain a deeper excision. Additionally, UCSP shows a higher en bloc resection rate, with lower rates of IRR, and emerges as a promising technique for training inexperienced endoscopists in polypectomy, given its experience-independent success in achieving R0 resection.

Resectability of Small Duodenal Tumors: A Randomized Controlled Trial Comparing Underwater Endoscopic Mucosal Resection and Cold Snare Polypectomy

INTRODUCTION

Underwater endoscopic mucosal resection (UEMR) and cold snare polypectomy (CSP) are novel endoscopic procedures for superficial nonampullary duodenal epithelial tumors (SNADET). However, consensus on how to use both procedures appropriately has not been established. In this study, we evaluated treatment outcomes of both procedures, including resectability.

METHODS

In this single-center randomized controlled study conducted between January 2020 and June 2022, patients with SNADET ≤12 mm were randomly allocated to UEMR and CSP groups. The primary end point was sufficient vertical R0 resection (SVR0), which was defined as R0 resection including a sufficient submucosal layer. We compared treatment outcomes including SVR0 rate between groups.

RESULTS

The SVR0 rate was significantly higher in the UEMR group than in the CSP group (65.6% vs 41.5%, P = 0.01). By contrast, the R0 resection rate was not significantly different between study groups (70.3% vs 61.5%, P = 0.29). The submucosal layer thickness was significantly greater in the UEMR group than in the CSP group (median 546 [range, 309-833] μm vs 69 [0-295] μm, P < 0.01). CSP had a shorter total procedure time (median 12 [range, 8-16] min vs 1 [1-3] min, P < 0.01) and fewer total bleeding events (9.4% vs 1.5%, P = 0.06).

DISCUSSION

UEMR has superior vertical resectability compared with CSP, but CSP has a shorter procedure time and fewer bleeding events. Although CSP is preferable for most small SNADET, UEMR should be selected for lesions that cannot be definitively diagnosed as mucosal low-grade neoplasias.

One-device colonoscopy: feasibility, cost savings, and plastic waste reduction by procedure indication, when performed by a high detecting colonoscopist

BACKGROUND

Cold forceps and snares are each effective for removing polyps of 1-3 mm, while snares are more effective for polyps of 4-10 mm in size. If, in the same patient, polyps of 1-3 mm are removed with forceps and those of 4-10 mm with snares, two devices are used. If cold snares are used to resect all lesions of 1-10 mm (one-device colonoscopy), there is a potential for lower costs and less plastic waste.

METHODS

A single high detecting colonoscopist prospectively measured the feasibility of cold snaring all colorectal lesions of ≤10 mm in size, along with the associated costs and plastic waste reduction.

RESULTS

677 consecutive lower gastrointestinal endoscopies (not for inflammatory bowel disease) were assessed. Of 1430 lesions of 1-3 mm and 1685 lesions of 4-10 mm in size, 1428 (99.9%, 95%CI 99.5%-100%) and 1674 (99.3%, 95%CI 98.8%-99.7%), respectively, were successfully resected using cold snaring. Among 379 screening and surveillance patients, universal cold snaring of lesions ≤10 mm saved 35 and 47 cold forceps per 100 screening and surveillance patients, respectively.

CONCLUSION

Cold snare resection of all lesions ≤10 mm (one-device colonoscopy) was feasible, and reduced costs and plastic waste.

Curriculum for training in endoscopic mucosal resection in the colon: European Society of Gastrointestinal Endoscopy (ESGE) Position Statement

Endoscopic mucosal resection (EMR) is the standard of care for the complete removal of large (≥ 10 mm) nonpedunculated colorectal polyps (LNPCPs). Increased detection of LNPCPs owing to screening colonoscopy, plus high observed rates of incomplete resection and need for surgery call for a standardized approach to training in EMR. 1 : Trainees in EMR should have achieved basic competence in diagnostic colonoscopy, < 10-mm polypectomy, pedunculated polypectomy, and common methods of gastrointestinal endoscopic hemostasis. The role of formal training courses is emphasized. Training may then commence in vivo under the direct supervision of a trainer. 2 : Endoscopy units training endoscopists in EMR should have specific processes in place to support and facilitate training. 3: A trained EMR practitioner should have mastered theoretical knowledge including how to assess an LNPCP for risk of submucosal invasion, how to interpret the potential difficulty of a particular EMR procedure, how to decide whether to remove a particular LNPCP en bloc or piecemeal, whether the risks of electrosurgical energy can be avoided for a particular LNPCP, the different devices required for EMR, management of adverse events, and interpretation of reports provided by histopathologists. 4: Trained EMR practitioners should be familiar with the patient consent process for EMR. 5: The development of endoscopic non-technical skills (ENTS) and team interaction are important for trainees in EMR. 6: Differences in recommended technique exist between EMR performed with and without electrosurgical energy. Common to both is a standardized technique based upon dynamic injection, controlled and precise snare placement, safety checks prior to the application of tissue transection (cold snare) or electrosurgical energy (hot snare), and interpretation of the post-EMR resection defect. 7: A trained EMR practitioner must be able to manage adverse events associated with EMR including intraprocedural bleeding and perforation, and post-procedural bleeding. Delayed perforation should be avoided by correct interpretation of the post-EMR defect and treatment of deep mural injury. 8: A trained EMR practitioner must be able to communicate EMR procedural findings to patients and provide them with a plan in case of adverse events after discharge and a follow-up plan. 9: A trained EMR practitioner must be able to detect and interrogate a post-endoscopic resection scar for residual or recurrent adenoma and apply treatment if necessary. 10: Prior to independent practice, a minimum of 30 EMR procedures should be performed, culminating in a trainer-guided assessment of competency using a validated assessment tool, taking account of procedural difficulty (e. g. using the SMSA polyp score). 11: Trained practitioners should log their key performance indicators (KPIs) of polypectomy during independent practice. A guide for target KPIs is provided in this document.

Colorectal cold snare polypectomy: Current standard technique and future perspectives

It has been shown that resection of adenomatous colorectal polyps can reduce mortality due to colorectal cancer. In daily clinical practice, simpler and safer methods of colorectal polypectomy have been sought to enable endoscopists to resect all detected lesions. Among these, cold snare polypectomy (CSP) is widely used in clinical practice because of its advantages in shortening procedure time, reducing delayed bleeding risk, and lowering treatment costs, while maintaining a similar complete resection rate for lesions smaller than 10 mm when compared to conventional hot snare polypectomy. This review introduces the findings of previous studies that investigated the efficacy and safety of the CSP procedure for nonpedunculated polyps smaller than 10 mm, and describes technical points to remember when practicing CSP based on the latest evidence, including using a thin wire snare specifically designed for CSP, and observing the surrounding mucosa of the resection site with chromoendoscopy or image-enhanced endoscopy to ensure that there is no residual lesion. This review also describes the potential of expanding the indication of CSP as a treatment for lesions larger than 10 mm, those with pedunculated morphology, those located near the appendiceal orifice, and for patients under continuous antithrombotic agent therapy. Finally, the perspective on optimal treatments for recurrent lesions after CSP is also discussed, despite the limited related evidence and data.

Progression in clinical application of cold snare resection technique in colorectal polyps

The cold snare resection technique has been recommended by European and American societies and gradually applied in clinical practice. However, due to the operating habits of endoscopists and the insufficient understanding of the cold resection technique, it has not been fully used in colorectal polyps. In this paper, we review the application status of cold snare resection technique, its use in patients treated with antithrombotic drugs, and postoperative histological changes.