Underwater endoscopic mucosal resection without submucosal injection (UEMR) for large colorectal polyps: A community-based series

Underwater Techniques in Gastrointestinal Endoscopy: Diving into the Depths

The endoscopic resection of gastrointestinal tract lesions embraces different types of techniques, ranging from conventional polypectomy/endoscopic mucosal resection (EMR) to the field of third-space endoscopy, including endoscopic submucosal dissection (ESD), full-thickness resection and peroral endoscopic myotomy (POEM). Parallelly, the advent of underwater techniques has served as an add-on for both basic and advanced procedures, since its first report in 2012. We aimed to provide a comprehensive update on the state of the art about the feasibility of underwater basic and advanced techniques for GI endoscopy. Underwater EMR (U-EMR) has proved effective and safe in treating > 10 mm sessile or flat or all-size recurrent colonic lesions. Conversely, although data show good effectiveness and safety for <10 mm lesions, it is preferred when high-grade dysplasia is suspected, favouring cold snare polypectomy for all other cases. Moreover, promising data are emerging regarding the feasibility of U-ESD for difficult-to-resect colonic lesions. U-EMR represents a standard of care for treating < 25 mm superficial non-ampullary duodenal epithelial tumours. Data regarding oesophageal, gastric and ampullary lesions remains limited to small cohorts. Finally, using water immersion for POEM has shown a reduction in procedure time compared to the CO2 insufflation technique for vessel coagulation, albeit in a single-centre experience. Based on these results, U-EMR has become a standard for treating intermediate-size colonic and non-ampullary duodenal lesions, as highlighted also in the European Society of Gastrointestinal Endoscopy guidelines. Promising results have been shown in third-space endoscopy studies, even though further prospective studies are awaited to standardise the technique for both ESD and POEM.

Does completing advanced endoscopy fellowship improve outcomes after endoscopic mucosal resection?

BACKGROUND

It was reported that about 60% of the physicians in the USA believed that their Gastroenterology fellowship poorly prepared them for large polyp resection. The aim of this study was to compare endoscopic mucosal resection (EMR) efficacy and complication rates between skilled general gastroenterologists who perform high volume of EMR and advanced endoscopists.

METHODS

We identified 140 patients with documented large colonic polyps treated by 4 providers using EMR technique at Carilion Clinic, in Roanoke, Virginia, USA between 01/01/2014-12/31/2017, with follow-up through 10-2018. Information on demographics, clinical and pathological features of high-risk polyps (i.e., size, histology, site, and degree of dysplasia), timing of surveillance endoscopies, tools used during resection, and skills of performing endoscopist's were extracted. The cumulative risks of polyp recurrence after first resection using EMR technique were estimated using Kaplan-Meier curves.

RESULTS

One hundred and forty patients were identified (mean age, 64.1±11.2 years; 47.1% males). Fifty-five polyps (39.3%) were removed by 2 skilled gastroenterologists and 85 (60.7%) were removed by advanced endoscopists. Most of the polyps resected were located in the right colon (63.6%) and roughly half of the polyps were removed in piecemeal fashion. At follow-up endoscopy, the advanced endoscopy group had lower polyp recurrence rates. The median recurrence after polypectomy was significantly different between the groups (0.88 and 1.03 years for skilled gastroenterologists who did not complete and completed EMR hands-on workshops; respectively vs. 3.99 years for the advanced endoscopist who did not complete EMR hands-on workshop, P=0.03).

CONCLUSIONS

There is a need for additional EMR training since polyp recurrence was significantly different between the groups despite high rates of piecemeal resection in the advanced endoscopy groups.

Safety and efficacy of underwater versus conventional endoscopic mucosal resection for colorectal polyps: Systematic review and meta-analysis of RCTs

Background and study aims Conventional endoscopic mucosal resection (C-EMR) is limited by low en-bloc resection rates, especially for large (> 20 mm) lesions. Underwater EMR (U-EMR) has emerged as an alternative for colorectal polyps and is being shown to improve en-bloc resection rates. We conducted a systematic review and meta-analysis comparing the two techniques. Methods Multiple databases were searched through November 2022 for randomized controlled trials (RCTs) comparing outcomes of U-EMR and C-EMR for colorectal polyps. Meta-analysis was performed to determine pooled proportions and relative risks (RRs) of R0 and en-bloc resection, polyp recurrence, resection time, and adverse events. Results Seven RCTs with 1458 patients (U-EMR: 739, C-EMR: 719) were included. The pooled rate of en-bloc resection was significantly higher with U-EMR vs C-EMR, 70.17% (confidence interval [CI] 46.68-86.34) vs 58.14% (CI 31.59-80.68), respectively, RR 1.21 (CI 1.01-1.44). R0 resection rates were higher with U-EMR vs C-EMR, 58.1% (CI 29.75-81.9) vs 44.6% (CI 17.4-75.4), RR 1.25 (CI 0.99-1.6). For large polyps (> 20 mm), en-bloc resection rates were comparable between the two techniques, RR 1.24 (CI 0.83-1.84). Resection times were comparable between U-EMR and C-EMR, standardized mean difference -1.21 min (CI -2.57 to -0.16). Overall pooled rates of perforation, and immediate and delayed bleeding were comparable between U-EMR and C-EMR. Pooled rate of polyp recurrence at surveillance colonoscopy was significantly lower with U-EMR than with C-EMR, RR 0.62 (CI 0.41-0.94). Conclusions Colorectal U-EMR results in higher en-bloc resection and lower recurrence rates when compared to C-EMR. Both techniques have comparable resection times and safety profiles.

Underwater endoscopic mucosal resection for colorectal lesions: Can it be an "Underwater" revolution?

Underwater endoscopic mucosal resection (UEMR) is a newly developed technique for the removal of colorectal, duodenal, esophageal, gastric, ampullary, and small intestinal lesions. We performed a PubMed literature search for articles reporting UEMR outcomes for colorectal polyps. Four randomized controlled trials, nine non-randomized prospective trials, 16 retrospective studies, and 27 case reports were selected for assessment of the efficacy and safety of UEMR. We summarized the therapeutic outcomes of UEMR in each category according to the lesion characteristics [small size (<10 mm), intermediate size (10-19 mm), large size (≥20 mm), recurrent lesion, and rectal neuroendocrine tumor], and calculated the incidence of adverse events among the included articles. As the treatment outcomes for small polyps appeared similar between UEMR and conventional endoscopic mucosal resection (CEMR), UEMR can be a standard procedure for small colorectal polyps suspicious for high-grade dysplasia to avoid incomplete removal of occult invasive cancer by cold snare polypectomy. As UEMR showed satisfactory outcomes for intermediate-size lesions and recurrent lesions after endoscopic resection, UEMR can be a standard procedure for these lesions. Regarding large lesions and rectal neuroendocrine tumors, comparisons of UEMR with current standard methods for them were lacking, and further investigations are warranted. Adverse events appeared comparable or less frequent for UEMR compared with CEMR but still existed. Therefore, careful implementation of this new technique in clinical practice is important for its widespread use.

Modified endoscopic mucosal resection techniques for treating precancerous colorectal lesions

Endoscopic mucosal resection (EMR) is a technique allowing efficacious and minimally invasive resection of precancerous lesions across the entire gastrointestinal tract. However, conventional EMR, involving injection of fluid into the submucosal space, is imperfect, given the high rate of recurrence of post-endoscopic resection adenoma, especially after piecemeal resection. In light of these observations, modifications of the technique have been proposed to overcome the weakness of conventional EMR. Some of them were designed to maximize the chance of en bloc resection-cap-assisted EMR, underwater EMR, tip-in EMR, precutting, assisted by ligation device-while others were designed to minimize the complications (cold EMR). In this review, we present their modes of action and summarize the evidence regarding their efficacy and safety.

Efficacy and histologic accuracy of underwater versus conventional endoscopic mucosal resection for large (>20 mm) colorectal polyps: a comparative review and meta-analysis

BACKGROUND AND AIMS

Major limitations with conventional EMR (C-EMR) include high rates of polyp recurrence and low en-bloc resection rates, especially for lesions >20 mm in size. Underwater EMR (U-EMR) has emerged as an alternate technique for en-bloc resection of larger lesions. We conducted a systematic review and meta-analysis comparing the efficacy and safety of the 2 techniques.

METHODS

Multiple databases were searched through June 2020 for studies that compared outcomes of U-EMR and C-EMR for colorectal lesions. Meta-analysis was performed to determine pooled odds ratios (ORs) of successful R0, en-bloc, and piecemeal resection of colorectal lesions. We compared the rates of polyp recurrence at follow-up, diagnostic accuracy for colorectal cancer, and adverse events with the 2 techniques.

RESULTS

Eleven studies, including 4 randomized controlled trials (RCTs) with 1851 patients were included in the final analysis. A total of 1071 lesions were removed using U-EMR, and 1049 lesions were removed using C-EMR. Although U-EMR had an overall superior en-bloc resection rate compared with C-EMR (OR, 1.9; 95% confidence interval [CI], 1-3.5; P = .04), both techniques were comparable in terms of polyps >20 mm in size (OR, 0.8; 95% CI, 0.3-2.1; P = .75), R0 resection (OR, 3.1; 95% CI, 0.74-12.6; P = .14), piecemeal resection (OR, 3.1; 95% CI, 0.74-12.6; P = .13), and diagnostic accuracy for colorectal cancer (OR, 1.1; 95% CI, 0.6-1.8; P = .82). There were lower rates of polyp recurrence (OR, 0.3; 95% CI, 0.1-0.8; P = .01) and incomplete resection (OR, 0.4; 95% CI, 0.2-0.5; P = .001) with U-EMR. Both techniques have comparable resection times and safety profiles.

CONCLUSIONS

Our results support the use of U-EMR over C-EMR for successful resection of colorectal lesions. Further randomized controlled trials are needed to evaluate the efficacy of U-EMR for resecting polyps >20 mm in size.

Current status of endoscopic diagnosis and treatment for superficial non-ampullary duodenal epithelial tumors

Though superficial non-ampullary duodenal epithelial tumors (SNADETs) have been traditionally considered rare, there is a growing detection under the development and widespread of endoscopic techniques in recent times. Many case studies have revealed early manifestations of lesions through advanced endoscopic technology, however, because of the low incidence of duodenal tumors and challenges in diagnosing, the preoperative diagnosis criteria have not been established so far. In spite of this, recently the increasing detection rate of early duodenal epithelial lesions enhances the demand for minimally invasive treatment as well. The most suitable therapeutic endoscopic modality to remove duodenal lesions should be selected according to the size, location and histological invasive depth of duodenal lesions. Nevertheless, due to the special anatomical structure of the duodenum, the incidence of complications is much higher than in any other part of the digestive tract. To prevent these adverse events prophylactically, a few novel strategies have been applied effectively after resection. This review describes the current status of preoperative endoscopic diagnosis and endoscopic resection approaches, as well as countermeasures for avoiding procedure-related complications.

Underwater Endoscopic Mucosal Resection for 10 mm or Larger Nonpedunculated Colorectal Polyps: A Systematic Review and Meta-Analysis

Background/Aims

Recent studies have reported the favorable outcomes of underwater endoscopic mucosal resection (UEMR) for colorectal polyps. We performed a systematic review and meta-analysis evaluating the efficacy and safety of UEMR for nonpedunculated polyps ≥10 mm.

Methods

We performed a comprehensive search of multiple databases (through May 2020) to identify studies reporting the outcomes of UEMR for ≥10 mm nonpedunculated colorectal polyps. The assessed outcomes were recurrence rate on the first follow-up, en bloc resection, incomplete resection, and adverse events after UEMR.

Results

A total of 1276 polyps from 16 articles were included in our study. The recurrence rate was 7.3% (95% confidence interval [CI], 4.3–12) and 5.9% (95% CI, 3.6–9.4) for nonpedunculated polyps ≥10 and ≥20 mm, respectively. For nonpedunculated polyps ≥10 mm, the en bloc resection, R0 resection, and incomplete resection rates were 57.7% (95% CI, 42.4–71.6), 58.9% (95% CI, 42.4–73.6), and 1.5% (95% CI, 0.8–2.6), respectively. The rates of pooled adverse events, intraprocedural bleeding, and delayed bleeding were 7.0%, 5.4%, and 2.9%, respectively. The rate of perforation and postpolypectomy syndrome was 0.8%.

Conclusions

Our systematic review and meta-analysis demonstrates that UEMR for nonpedunculated colorectal polyps ≥10 mm is safe and effective with a low rate of recurrence.