Underwater colorectal EMR: remodeling endoscopic mucosal resection

Outcomes of underwater endoscopic mucosal resection for colorectal polyps-Insights from western India

INTRODUCTION

Underwater endoscopic mucosal resection (uEMR) represents an alternative to conventional EMR for resection of sessile colorectal polyps. We aimed at assessing the efficacy and safety of uEMR for sessile colorectal polyps.

METHODS

A retrospective analysis of endoscopy database was done for patients who underwent uEMR for sessile colorectal polyps more than 10 mm in size without any features of sub-mucosal invasion from two tertiary care centres in western India between January 2021 and June 2023. Exclusion criteria were other modes of endoscopic resection. Primary outcome was rate of en bloc resection. Secondary outcomes were complete resection rate, adverse events and recurrence rate.

RESULTS

During the study period, 159 patients with 261 lesions met the study inclusion. Mean lesion size was 1.935 ± 0.71 cm with most lesion located in the rectum (75, 28.73%) followed by sigmoid colon (69, 26.43%). Most lesions had a Paris 0-Is morphology (192, 73.56%). Japan NBI Expert Team (JNET) IIa pattern was seen on narrow band imaging (NBI) in 221 (84.67%) lesions. Complete resection was achieved in 98.46% lesions (257/261). En bloc resection was achieved in 91.82% (236/257) lesions. Complications were seen in 6.8%, all of which were managed endoscopically. Recurrence was seen in 3.1% of polyps on follow-up.

CONCLUSION

uEMR is a safe and efficacious technique for endoscopic resection for sessile colorectal polyps with high rates of en bloc resection for polyps more than 10 mm size.

Endoscopic diagnosis and treatment of superficial non-ampullary duodenal epithelial tumors: A review

The surface of the small bowel mucosa is covered more than any other section of the digestive canal; however, the overall prevalence of small bowel tumors of the whole gastrointestinal tract is evidently low. Owing to the improvement in endoscopic techniques, the prevalence of small bowel tumors has increased across multiple countries, which is mainly due to an increase in duodenal tumors. Superficial non-ampullary duodenal epithelial tumors (SNADETs) are defined as tumors originating from the non-ampullary region in the duodenum that share similarities and discrepancies with their gastric and colorectal counterparts in the pathogenesis and clinicopathologic characteristics. To date, white light endoscopy (WLE) remains the cornerstone of endoscopic diagnosis for SNADETs. Besides, narrow-band imaging (NBI) techniques and magnifying endoscopy (ME) have been widely used in the clinic and endorsed by multiple guidelines and consensuses for SNADETs' evaluation. Confocal laser endomicroscopy (CLE), endocytoscopy (ECS), and artificial intelligence (AI) are also up-and-coming methods, showing an exceptional value in the diagnosis of SNADETs. Similar to the endoscopic treatment for colorectal polyps, the choices for SNADETs mainly include cold snare polypectomy (CSP), endoscopic mucosal resection (EMR), endoscopic submucosal dissection (ESD), and laparoscopic endoscopic cooperative surgery (LECS). However, owing to the narrow lumen, rich vascularity, weak muscle layer, abundant Brunner's gland, and the hardship of endoscope control, the duodenum ranks as one of the most dangerous operating areas in the digestive tract. Therefore, endoscopists must anticipate the difficulties in endoscopic maneuverability, remain aware of the increased risk of complications, and then select the appropriate treatment according to the advantages and disadvantages of each method.

Underwater versus conventional EMR for nonpedunculated colorectal lesions: a randomized clinical trial

BACKGROUND AND AIMS

Conventional endoscopic mucosal resection (CEMR) is the standard modality for removing nonpedunculated colorectal lesions. Underwater endoscopic mucosal resection (UEMR) has emerged as an alternative method. There are few comparative studies between these techniques, especially evaluating recurrence. Therefore, the purpose of this trial was to compare CEMR and UEMR for the resection of colorectal lesions with respect to efficacy, safety, and recurrence rate.

METHODS

This was a randomized controlled trial of UEMR versus CEMR for naïve and nonpedunculated lesions measuring between 10 and 40 mm. The primary outcome was adenoma recurrence at 6 months after the resection. Secondary outcomes were rates of technical success, en bloc resection, and adverse events. Block randomization was used to assign patients. Tattooing was performed to facilitate localization of the scars and eventual recurrences. Endoscopic follow-up was scheduled at 6 months after the procedure. The sites of resections were examined with white-light imaging, narrow-band imaging (NBI), and conventional chromoscopy with indigo carmine followed by biopsies.

RESULTS

One hundred five patients with 120 lesions were included, with a mean size of 17.5 ± 7.1 (SD) mm. Sixty-one lesions were resected by UEMR and 59 by CEMR. The groups were similar at baseline regarding age, sex, average size, and histologic type. Lesions in the proximal colon in the CEMR group corresponded to 83% and in the UEMR group to 67.8% (P = .073). There was no difference between groups regarding success rate (1 failure in each group) and en bloc resection rate (60.6% UEMR vs 54.2% CEMR, P = .48). Intraprocedural bleeding was observed in 5 CEMRs (8.5%) and 2 UEMRs (3.3%) (P = .27). There was no perforation or delayed hemorrhage in either groups. Recurrence rate was higher in the CEMR arm (15%) than in the UEMR arm (2%) (P = .031). Therefore, the relative risk of 6-month recurrence rate in the CEMR group was 7.5-fold higher (95% CI, 0.98-58.20), with a number needed to treat of 7.7 (95% CI, 40.33-4.22). The higher recurrence rate in the CEMR group persisted only for lesions measuring 21 to 40 mm (35.7% vs 0%; P = .04).

CONCLUSION

This study demonstrated that UEMR was associated with a lower adenoma recurrence rate than was CEMR. Both endoscopic techniques were effective and had similar rates of adverse events for the treatment of nonpedunculated colorectal lesions.

Cap-assisted EMR versus standard inject and cut EMR for treatment of large colonic laterally spreading tumors: a randomized multicenter study (with videos)

BACKGROUND AND AIMS

Piecemeal EMR of colorectal laterally spreading tumors (LSTs) >20 mm is effective. Experience is limited in the use of cap-assisted EMR (EMR-C) for resection of colonic lesions. We compared the efficacy and the safety of EMR-C for the removal of colonic LSTs ≥30 mm with "inject-and-cut" standard EMR (EMR-S).

METHODS

In this randomized trial from 4 Italian centers, 138 patients were treated with EMR-C and 102 with EMR-S. The rates of residual lesions, percentage of recurrence after 12 months, and adverse events were evaluated.

RESULTS

One hundred forty-three lesions were resected with EMR-C and 102 with EMR-S. Argon plasma coagulation (APC) was used as adjunctive treatment in 2.9% of EMR-Cs and in 22.5% of EMR-Ss (P < .001). The median time required was 20 minutes for EMR-C and 30 minutes for EMR-S (P < .001). Adverse events (AEs) occurred in 14 EMR-Cs (10.1%; 2 perforations, 11 bleeding events, and 1 stenosis) and in 22 EMR-Ss (21.6%; 1 perforation and 21 bleeding events) (P = .017). Intraprocedural AEs occurred in 3.6% of EMR-Cs and 16.7% of EMR-Ss (P = .001). Overall, residual lesions within 12 months were found to be significantly higher with EMR-S (32 patients, 31.4%) than with EMR-C (8 patients, 5.8%) (P < .001). Recurrence at follow-up colonoscopy in 12 months occurred in 7 EMR-Cs (5.1%) and 17 EMR-Ss (16.7%; P < .001).

CONCLUSIONS

The study demonstrated the feasibility and safety of EMR-C for removing large colorectal LSTs, with higher eradication rates, shorter resection time, and less use of APC when compared with EMR-S. (Clinical trial registration number: NCT03498664.).

Underwater versus conventional cold snare polypectomy of colorectal polyps 4-9 mm in diameter: a prospective randomized controlled trial

BACKGROUND AND AIMS

Cold snare polypectomy (CSP) has been reported as safe and effective method for the removal of small colorectal polyps. However, some studies showed low R0 resection rate. Underwater endoscopic mucosal resection is an effective technique to increase the proportions of complete resection. Therefore, the aim was to compare the rate of R0 resection of colorectal polyps 4-9 mm in diameter between conventional CSP (C-CSP) and underwater CSP (U-CSP).

METHODS

This study was a prospective randomized controlled trial. A total of 198 polyps (4-9 mm) in 110 patients were enrolled between December 2019 and June 2020. The polyps were randomized to be treated with either C-CSP (100 polyps) or U-CSP (98 polyps).

RESULTS

The R0 resection rate was significantly higher in U-CSP group than in C-CSP groups (84.7% vs. 59.0%; p < 0.001). The polyp retrieval rate of C-CSP and U-CSP was 94.5% and 100% (p = 0.030). The rate of polyp fragmentation of C-CSP and U-CSP group was 5.3% and 0% (p = 0.027). The resection time and retrieval time were longer in C-CSP than U-CSP (45.0 ± 37.7 s vs. 34.1 ± 21.2 s, p = 0.032 and 51.9 ± 67.7 s vs. 12.7 ± 12.4 s, p < 0.001). No clinically significant bleeding or perforation occurred in either group.

CONCLUSIONS

The results of this study were excellent with U-CSP of 4-9 mm colorectal polyps in terms of R0 resection, polyp retrieval and fragmentation rate, and procedure/retrieval time. Therefore, U-CSP is a safe and effective technique for removing colorectal polyps 4-9 mm in diameter. KCT (0004530).

From advanced diagnosis to advanced resection in early neoplastic colorectal lesions: Never-ending and trending topics in the 2020s

Colonoscopy represents the most widespread and effective tool for the prevention and treatment of early stage preneoplastic and neoplastic lesions in the panorama of cancer screening. In the world there are different approaches to the topic of colorectal cancer prevention and screening: different starting ages (45-50 years); different initial screening tools such as fecal occult blood with immunohistochemical or immune-enzymatic tests; recto-sigmoidoscopy; and colonoscopy. The key aspects of this scenario are composed of a proper bowel preparation that ensures a valid diagnostic examination, experienced endoscopist in detection of preneoplastic and early neoplastic lesions and open-minded to upcoming artificial intelligence-aided examination, knowledge in the field of resection of these lesions (from cold-snaring, through endoscopic mucosal resection and endoscopic submucosal dissection, up to advanced tools), and management of complications.

Depth of the cutting plane with underwater and conventional endoscopic mucosal resection: Post-hoc analysis of a randomized study

BACKGROUND AND AIM

A multicenter randomized controlled trial reported a better R0 resection rate for intermediate-sized (10-20 mm) colorectal polyps with underwater endoscopic mucosal resection (UEMR) than conventional endoscopic mucosal resection (CEMR). To clarify whether UEMR removes enough submucosal tissue in the removal of unpredictable invasive cancers, we investigated the cutting plane depth with UEMR versus CEMR.

METHODS

This was a post-hoc analysis of a randomized controlled trial in which 210 intermediate-sized colorectal polyps were removed in five Japanese hospitals. One pathologist and two gastroenterologists independently reviewed all resected specimens and measured the cutting plane depth. The cutting plane depth was evaluated as (i) maximum depth of submucosal layer and (ii) mean depth of submucosal layer, calculated using a virtual pathology system.

RESULTS

We identified 168 appropriate specimens for the evaluation of the cutting plane depth, resected by UEMR (n = 88) and CEMR (n = 80). The median resection depth was not significantly different between UEMR and CEMR specimens, regardless of the measurement method ([i] 1317 vs 1290 μm, P = 0.52; [ii] 619 vs 545 μm, P = 0.32). All specimens in the UEMR and CEMR groups contained substantial submucosa and no muscularis propria.

CONCLUSIONS

The cutting plane depth with UEMR was comparable with that with CEMR. UEMR can be a viable alternative method that adequately resects the submucosal layer for the histopathological assessment of unpredictable submucosal invasive cancers.

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.

Underwater vs Conventional Endoscopic Mucosal Resection of Large Sessile or Flat Colorectal Polyps: A Prospective Randomized Controlled Trial

BACKGROUND & AIMS

Conventional endoscopic mucosal resection (CEMR) with submucosal injection is the current standard for the resection of large, nonmalignant colorectal polyps. We investigated whether underwater endoscopic mucosal resection (UEMR) is superior to CEMR for large (20-40mm) sessile or flat colorectal polyps.

METHODS

In this prospective randomized controlled study, patients with sessile or flat colorectal polyps between 20 and 40 mm in size were randomly assigned to UEMR or CEMR. The primary outcome was the recurrence rate after 6 months. Secondary outcomes included en bloc and R0 resection rates, number of resected pieces, procedure time, and adverse events.

RESULTS

En bloc resection rates were 33.3% in the UEMR group and 18.4% in the CEMR group (P = .045); R0 resection rates were 32.1% and 15.8% for UEMR vs CEMR, respectively (P = .025). UEMR was performed with significantly fewer pieces compared to CEMR (2 pieces: 45.5% UEMR vs 17.7% CEMR; P = .001). The overall recurrence rate did not differ between both groups (P = .253); however, subgroup analysis showed a significant difference in favor of UEMR for lesions of >30 mm to ≤40 mm in size (P = .031). The resection time was significantly shorter in the UEMR group (8 vs 14 minutes; P < .001). Adverse events did not differ between both groups (P = .611).

CONCLUSIONS

UEMR is superior to CEMR regarding en bloc resection, R0 resection, and procedure time for large colorectal lesions and shows significantly lower recurrence rates for lesions >30 mm to ≤40 mm in size. UEMR should be considered for the endoscopic resection of large colorectal polyps.

Curative value of underwater endoscopic mucosal resection for submucosally invasive colorectal cancer

BACKGROUND AND AIM

Occasionally, colorectal tumors without characteristics of deep submucosal invasion are found to be invasive upon pathological evaluation after endoscopic resection (ER). Because the resection depth for underwater endoscopic mucosal resection (UEMR) has not been clarified, we evaluated the feasibility of UEMR for pathologically invasive colorectal cancer (pT1-CRC).

METHODS

We retrospectively investigated data on the backgrounds and outcomes of patients with pT1-CRC who underwent UEMR between January 2014 and June 2019 at our institute. As a reference standard, the backgrounds and outcomes of pT1-CRCs that had undergone conventional EMR (CEMR) were also investigated.

RESULTS

Thirty-one patients (median age, 68 years [range, 32-88 years]; 22 men [71%]) were treated with UEMR. Median lesion size was 17 mm (range, 6-50 mm). The endoscopic complete resection rate was 100%. The overall en bloc resection rate was 77%, and the VM0, HM0, and R0 resection rates were 81%, 58%, and 55%, respectively. In cases of pT1a (invasion <1000 μm)-CRC (n = 14), the en bloc, VM0, and R0 resection rates were 92%, 100%, and 71%, respectively. Seventeen patients (five with risk factors for lymph node metastasis and 12 without) were followed up, and no local recurrence and distant metastasis were observed during the follow-up period (median follow-up period, 18 months [range, 6-62 months]) after UEMR. The outcomes of UEMR seemed to be comparable with those of CEMR (n = 32).

CONCLUSIONS

The VM0 rate of UEMR for pT1-CRC, especially for pT1a-CRC, without characteristics of deep submucosal invasion seems feasible.

Propensity score-matched analysis of endoscopic resection for recurrent colorectal neoplasms: A pilot study

BACKGROUND AND AIM

Local residual/recurrent colorectal lesions after endoscopic resection (ER) are difficult to treat with conventional ER. Underwater endoscopic mucosal resection (UEMR) and endoscopic submucosal dissection (ESD) are reportedly effective. We investigated the appropriate indications of ESD and UEMR for recurrent colorectal lesions.

METHODS

This single-center, retrospective, observational study was conducted at a tertiary cancer institute. Patients who underwent UEMR or ESD for residual/recurrent colorectal lesions after ER from October 2013 to February 2019 were enrolled. Propensity score matching was performed between the UEMR and ESD groups to compare the clinical characteristics, treatment, and outcomes.

RESULTS

In total, 30 UEMRs and 21 ESDs were performed. Median (range) diameter of the lesions was 8 mm (2-22 mm) in UEMR and 15 mm (2-58 mm) in ESD. Median procedure time in UEMR was significantly shorter than that of ESD (4 min [2-15 min] vs 70 min [17-193 min], P < 0.001). En bloc and complete resection rates of ESD were significantly higher than that of UEMR (73% vs 100%, 41% vs 81%, respectively). No adverse events occurred with UEMR, but there were two cases (10%) of delayed perforation with ESD. Neither group reported recurrence after treatment. Propensity score-matched cases showed significantly shorter procedure time and hospitalization period in UEMR than in ESD.

CONCLUSIONS

The outcomes of UEMR and ESD were comparable. UEMR could be a useful salvage therapy for small local residual/recurrent colorectal lesions after ER with shorter procedure time and hospitalization period.

Higher rate of en bloc resection with underwater than conventional endoscopic mucosal resection: A meta-analysis

OBJECTIVES

Previous meta-analysis including nonrandomized studies showed marginal benefit of underwater endoscopic mucosal resection(U-EMR) compared to conventional EMR(C-EMR) in terms of polypectomy outcomes. We evaluated U-EMR compared to C-EMR in the treatment of colorectal polyps with respect to effectiveness and safety by analyzing only randomized controlled trials(RCTs).

MATERIAL AND METHODS

PubMed and Cochrane Library databases were searched for RCTs published until 11/2020, evaluating U-EMR vs. C-EMR regarding en bloc resection, post-endoscopic resection adenoma recurrence, complete resection, adverse events rates and difference in resection time. Abstracts from Digestive Disease Week, United European Gastroenterology Week and ESGE Days meetings were also searched. Effect size on outcomes is presented as risk ratio(RR; 95% confidence interval[CI]) or mean difference(MD; 95%CI). The I2 test was used for quantifying heterogeneity, while Grading of Recommendations Assessment, Development and Evaluation(GRADE) was used to assess strength of evidence.

RESULTS

Six RCTs analyzing outcomes from 1157 colorectal polypectomies(U-EMR589;C-EMR,568) were included. U-EMR associated with significant higher rate of en bloc resection compared to C-EMR [RR(95%CI):1.26(1.01-1.58); Chi² for heterogeneity=30.43, P<0.0001; I²=84%, GRADE: Very low]. This effect was more prominent regarding resection of polyps sized ≥20 mm compared to polyps <20 mm [RR(95%CI):1.64(1.22-2.20) vs. 1.10(0.98-1.23)]. Post-resection recurrence [RR(95%CI):0.52(0.28-0.94);GRADE:Low] was lower significantly in U-EMR group. In contrast, no significant difference was detected between U-EMR and C-EMR regarding complete resection [RR(95%CI): 1.06(0.91-1.24) GRADE:Very low] and adverse events occurrence[RR(95%CI):1.00 (0.72-1.39); GRADE:Low].

CONCLUSION

Meta-analysis of RCTs supports that U-EMR resection achieves higher rate of en bloc resection compared to conventional EMR. This effect is driven when resecting large(≥20 mm) polyps.

Water-assisted colonoscopy: an international modified Delphi review on definitions and practice recommendations

BACKGROUND AND AIMS

Since 2008, a plethora of research studies has compared the efficacy of water-assisted (aided) colonoscopy (WAC) and underwater resection (UWR) of colorectal lesions with standard colonoscopy. We reviewed and graded the research evidence with potential clinical application. We conducted a modified Delphi consensus among experienced colonoscopists on definitions and practice of water immersion (WI), water exchange (WE), and UWR.

METHODS

Major databases were searched to obtain research reports that could potentially shape clinical practice related to WAC and UWR. Pertinent references were graded (Grading of Recommendations, Assessment, Development and Evaluation). Extracted data supporting evidence-based statements were tabulated and provided to respondents. We received responses from 55 (85% surveyed) experienced colonoscopists (37 experts and 18 nonexperts in WAC) from 16 countries in 3 rounds. Voting was conducted anonymously in the second and third round, with ≥80% agreement defined as consensus. We aimed to obtain consensus in all statements.

RESULTS

In the first and the second modified Delphi rounds, 20 proposed statements were decreased to 14 and then 11 statements. After the third round, the combined responses from all respondents depicted the consensus in 11 statements (S): definitions of WI (S1) and WE (S2), procedural features (S3-S5), impact on bowel cleanliness (S6), adenoma detection (S7), pain score (S8), and UWR (S9-S11).

CONCLUSIONS

The most important consensus statements are that WI and WE are not the same in implementation and outcomes. Because studies that could potentially shape clinical practice of WAC and UWR were chosen for review, this modified Delphi consensus supports recommendations for the use of WAC in clinical practice.

The efficacy and safety of underwater endoscopic mucosal resection for ≥10-mm colorectal polyps: systematic review and meta-analysis

BACKGROUND

Underwater endoscopic mucosal resection (UEMR) is a promising strategy for nonpedunculated colorectal polyp removal. However, the efficacy and safety of the technique for the treatment of ≥ 10-mm colorectal polyps remain unclear. We aimed to comprehensively assess the efficacy and safety of UEMR for polyps sized 10-19 mm and ≥ 20 mm.

METHODS

PubMed, EMBASE, and the Cochrane Library databases were searched for relevant articles from January 2012 to November 2019. Primary outcomes were the rates of adverse events and residual polyps. Secondary outcomes were the complete resection, en bloc resection, and R0 resection rates.

RESULTS

18 articles including 1142 polyps from 1093 patients met our inclusion criteria. The overall adverse event and residual polyp rates were slightly lower for UEMR when removing colorectal polyps of 10-19 mm vs. ≥ 20 mm (3.5 % vs. 4.3 % and 1.2 % vs. 2.6 %, respectively). The UEMR-related complete resection rate was slightly higher for colorectal polyps of 10-19 mm vs. ≥ 20 mm (97.9 % vs. 92.0 %). However, the en bloc and R0 resection rates were dramatically higher for UEMR removal of polyps of 10-19 mm vs. ≥ 20 mm (83.4 % vs. 36.1 % and 73.0 % vs. 40.0 %, respectively). In addition, univariate meta-regression revealed that polyp size was an independent predictor for complete resection rate (P = 0.03) and en bloc resection (P = 0.01).

CONCLUSIONS

UEMR was an effective and safe technique for the removal of ≥ 10-mm nonpedunculated colorectal polyps. However, UEMR exhibited low en bloc and R0 resection rates for the treatment of ≥ 20-mm polyps.

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.

Underwater endoscopic mucosal resection of adenomas and colorectal serrated lesions: a prospective clinical study

Background

Underwater endoscopic mucosal resection (UEMR) without submucosal injection has been described as an alternative technique to the endoscopic resection of adenomas and colorectal serrated lesions. We aimed to assess the feasibility, safety, and efficacy of UEMR in a Brazilian setting.

Methods

This was a prospective observational study of consecutive patients who underwent UEMR between January and July 2019, in a single tertiary care center. Inclusion criteria were lesions without endoscopic stigmata of deep submucosal invasion in patients referred for endoscopic resection of colorectal adenomas, and serrated lesions detected in a previous colonoscopy. The following features were assessed: complete resection rate, en bloc resection rate, resection time, adverse events, and resection infeasibility.

Results

A total of 36 patients underwent UEMR for 51 colorectal lesions. The mean/median lesion size was 16.24/13 mm and the mean/median resection time was 16.97/9.19 min. Histopathology revealed the following: tubular adenoma (43.1%), tubulovillous adenoma (13.7%), serrated lesions (41.2%), and intramucosal adenocarcinoma (2%). Complete resection was achieved in 86.3% of cases; 52.9% of the lesions were removed en bloc, while 47.1% were resected in a piecemeal fashion. UEMR was feasible in 96.1% of cases and failed on 2 occasions, requiring conversion to standard endoscopic mucosal resection. Minor intraoperative bleeding occurred in 5 patients (9.8%) and only 1 presented with delayed bleeding (2%), all controlled endoscopically.

Conclusion

UEMR for removal of adenomas and colorectal serrated lesions was demonstrated to be feasible, safe and effective.

[Endoscopic diagnosis, treatment, and follow-up of polyps of the lower gastrointestinal tract]

BACKGROUND

The endoscopic management of polyps of the lower gastrointestinal tract (l-GIT) has emerged in recent years as a result of numerous technological innovations. However, proven expertise and experience are essential.

OBJECTIVES

Presentation of novel and standard techniques and best-practice recommendations for the characterization and resection of l‑GIT polyps.

METHODS

Recent specialist literature and current guidelines.

RESULTS

High-definition endoscopy should be the standard when performing colonoscopy. The (virtual) chromoendoscopy can improve detection and characterization of polyps, but always requires special expertise and experience of the endoscopist in advanced endoscopic imaging. In this regard, computer-aided-diagnosis (CAD) systems have the potential to support endoscopists in the future. Pedunculated polyps should be removed with a hot snare. Small flat polyps can be resected by cold snare or large forceps. Large, non-pedunculated polyps should be treated in an interdisciplinary approach at a referral center with long-standing experience depending on its malignancy potential. After complete resection of small adenoma without high grade dysplasia, surveillance endoscopy is recommended after 5-10 years. Patients with large adenoma or high grade dysplasia should undergo endoscopy after 3 years and patients with multiple adenoma earlier than 3 years. After incomplete or piecemeal resection or insufficient bowel preparation, near-term endoscopy is recommended.

CONCLUSIONS

Adequate characterization and treatment are essential for the appropriate management of l‑GIT polyps.

Feasibility and safety of modified underwater endoscopic mucosal resection for colorectal polyps

BACKGROUND

Conventional endoscopic mucosal resection (EMR) with submucosal injection has been widely performed to remove colorectal polyps, although it often makes sessile lesions flattened and enlarged, resulting in the failure of lesion snaring. Air deflation and water immersion during underwater EMR (UEMR) sometimes interfere with the exposure of colorectal polyps. Modified UEMR may facilitate the resection of colorectal polyps due to integrating the advantages of EMR and UEMR.

AIM

To investigate the feasibility and safety of the modified UEMR in the treatment of colorectal polyps.

METHODS

Fifty-nine patients with 76 colorectal polyps treated by modified UEMR were enrolled in the study from July 2015 to June 2019, and compared with 43 patients with 65 colorectal polyps treated by UEMR during the same period. All lesions were classified as Paris Is or IIa, and the size of the polyp ranged from 1 cm to 3 cm in diameter. Endoscopic procedure was as follows: Once observed, the polyp was completely immersed by warm water infusion. The polyp was placed in the 6 o'clock direction. Following submucosal injection with normal saline plus methylene blue, an appropriate snare was used for en bloc resection. The mucosal defect was closed with clips. The excised specimen was sent for pathological evaluation after crystal violet staining.

RESULTS

All the 76 lesions in the study group were successfully resected by modified UEMR. Among them, 64 polyps less than 2 cm in size received en bloc resection. In 12 polyps ranging 2-3 cm in size, 5 received en bloc resection and 7 received piecemeal UEMR. The overall en bloc resection rate was 91%; the rate for those polyps < 2 cm was 100%, and the rate for polyps ranging from 2 cm to 3 cm was 42%. All the 65 lesions in the control group were successfully treated by conventional UEMR. Of 58 lesions less than 2 cm in size, 49 underwent en bloc resection and the other 9 underwent additional argon plasma coagulation (APC) due to residual lesion. Of 7 lesions ranging from 2 cm to 3 cm in size, 2 underwent en bloc resection, 1 undewent additional APC due to residual lesion, and the other 5 underwent piecemeal UEMR or were converted to modified endoscopic submucosal dissection. The overall en bloc resection rate in the control group was 76%; the rate for the lesions < 2 cm was 84%, and that for lesions 2-3 cm was 14%. During operation, minor bleeding occurred in 9 patients of the study group and 13 patients of the control group. There were no complications such as delayed bleeding and perforation in either group. During the follow-up period, local recurrence was found in 2 patients of the study group, and 9 patients of the control group.

CONCLUSION

Compared with conventional UEMR, modified UEMR can provide more excellent exposure for polyps, and achieve higher en bloc resection rate by discontinuous suction during tightening of the snare, resulting in a high complete resection rate and low recurrence rate.

Effectiveness and safety of underwater techniques in gastrointestinal endoscopy: a comprehensive review of the literature

BACKGROUND

Conventional endoscopic resection techniques such as endoscopic mucosal resection (EMR) or endoscopic submucosal dissection (ESD), represent the standard of care for treatment of superficial gastrointestinal lesions. In 2012 a novel technique called underwater endoscopic mucosal resection (U-EMR) was described by Binmoeller and colleagues. This substantial variation from the standard procedure was afterwards applied at endoscopic submucosal dissection (U-ESD) and recently proposed also for peroral endoscopic myotomy (U-POEM) and endoscopic full-thickness resection (U-EFTR).

METHODS

This paper aims to perform a comprehensive review of the current literature related to supporting the underwater resection techniques with the aim to evaluate their safety and efficacy.

RESULTS

Based on the current literature U-EMR appears to be feasible and safe. Comparison studies showed that U-EMR is associated with higher "en-bloc" and R0 resection rates for colonic lesions, but lower "en-bloc" and R0 resection rates for duodenal non-ampullary lesions, compared to standard EMR. In contrast to U-EMR, little evidence supporting U-ESD are currently available. A single comparison study on gastric lesions showed that U-ESD had shorter procedural times and allowed a similar "en-bloc" resection rates compared to standard ESD. No comparison studies between U-ESD and ESD are available for colonic lesions. Finally, only some anecdotal experiences have been reported for U-POEM or U-EFTR, and the feasibility and effectiveness of these techniques need to be further investigated.

CONCLUSIONS

Further prospective studies are necessary to better explore the advantages of underwater techniques compared to the respective standards of care, especially in the setting of U-ESD where consistent data are lacking and where standardization of the technique is needed.

Short and long-term outcomes of underwater EMR compared to the traditional procedure in the real clinical practice

BACKGROUND AND AIMS

underwater endoscopic mucosal resection (U-EMR) has been recently described as an alternative to endoscopic mucosal resection (EMR) for flat colorectal polyps. However, the real applications remain unclear due to the lack of comparative studies.

METHODS

a multi-centric prospective study was performed from November 2016 to December 2017. All lesions larger than 15 mm that were resected with both techniques were included in the study. The samples were matched using the size, morphology, site and access (SMSA) score as a reference. The efficacy, efficiency and adverse events rates were compared.

RESULTS

a total of 162 resections were collected (112 EMR and 50 U-EMR) with an average size of 25 mm. U-EMR achieved better results for the en bloc resection rate (49 vs 62%; p = 0.08) and there were no cases of an incomplete resection (10.7 vs 0%; p = 0.01). U-EMR was faster than EMR and there were no differences in the adverse events rate. Furthermore, U-EMR tended to achieve better results in terms of recurrence. Performing the resection in emersion appeared to prevent the cautery artefact, especially in sessile serrated adenomas.

CONCLUSION

in the real clinical practice, U-EMR and EMR are equivalent in terms of efficacy and safety. Furthermore, U-EMR may be a feasible approach to prevent cautery artefact, allowing an accurate pathologic assessment.

[Interventional endoscopy in the gastrointestinal tract : Indications and limitations]

The spectrum of endoscopic techniques has been greatly enlarged in recent years. Lesions and also (iatrogenic) complications that required surgical procedures in the past can now often be treated endoscopically. Advances in endoscopic mucosal resection and submucosal dissection also enable the resection of large or laterally spreading polyps in the gastrointestinal tract. Full-thickness resection is also possible by means of specially designed clips. By the creation of a submucosal tunnel submucosal lesions can be completely excised and the muscle fibers of the lower esophageal sphincter can be endoscopically severed in achalasia patients. Endosonography-guided interventions have developed into the standard procedure for complicated pancreatitis and the use of cholangioscopy offers new therapeutic procedures for the bile and pancreatic ducts. In this continuing medical education article interventional endoscopic techniques are presented and critically evaluated.

UNDERWATER ENDOSCOPIC MUCOSAL RESECTION FOR NON-PEDUNCULATED COLORECTAL LESIONS. A PROSPECTIVE SINGLE-ARM STUDY

BACKGROUND

Underwater endoscopic mucosal resection (UEMR) has emerged as a revolutionary method allowing resection of colorectal lesions without submucosal injection. Brazilian literature about this technique is sparse.

OBJECTIVE

The aim of this study was evaluate the efficacy and safety of UEMR technique for removing non-pedunculated colorectal lesions in two Brazilian tertiary centers.

METHODS

This prospective study was conducted between June 2016 and May 2017. Naïve and non-pedunculated lesions without signs of submucosal invasion were resected using UEMR technique.

RESULTS

A total of 55 patients with 65 lesions were included. All lesions, except one, were successfully and completely removed by UEMR (success rate 98.5%). During UEMR, two cases of bleeding were observed (3.0%). One patient had abdominal pain on the day after resection without pneumoperitoneum. There was no perforation or delayed bleeding.

CONCLUSION

This study supports the existing data indicating acceptable rates of technical success, and low incidence of adverse events with UEMR. The results of this Brazilian study were consistent with previous abroad studies.

Future of Endoscopy: Brief review of current and future endoscopic resection techniques for colorectal lesions

Endoscopic treatment of colorectal lesions has seen major developments in the last decade. It is now considered curative for intramucosal and superficial submucosal cancers. Endoscopic Mucosal Resection in expert hands has very good outcomes with low complication rates but recurrence and inadequate treatment of early cancers remain an issue. This has led to a technical evolution that can lead to one piece resection of neoplasia. This includes a range of techniques from knife assisted snare resection (KAR), endoscopic submucosal dissection (ESD) to full thickness resections. This article reviews all the resection techniques and the evidence base behind them.

Comparison of underwater endoscopic mucosal resection and endoscopic submucosal dissection of rectal neuroendocrine tumors (with videos)

BACKGROUND AND AIMS

The first choice of treatment for rectal neuroendocrine tumors (NETs) ≤10 mm in size is endoscopic resection. However, because rectal NETs usually invade the submucosal layer, achieving R0 resection is difficult. Endoscopic submucosal dissection (ESD) has a high R0 resection rate, and underwater endoscopic mucosal resection (UEMR) was recently introduced to ensure a negative resection margin easily and safely. The aim of this study was to evaluate the efficacy and safety of UEMR versus ESD for rectal NETs ≤10 mm in size.

METHODS

This retrospective observational study enrolled 115 patients with rectal NETs ≤10 mm in size who underwent ESD or UEMR between January 2015 and July 2019 at the National Cancer Center, Korea. The differences in R0 resection rate, adverse event rate, and procedure time between the ESD and UEMR groups were evaluated.

RESULTS

Of the 115 patients, 36 underwent UEMR and 79 underwent ESD. The R0 resection rate was not different between the UEMR and ESD groups (UEMR vs ESD, 86.1% vs 86.1%, P = .996). The procedure time was significantly shorter with UEMR (UEMR vs ESD, 5.8 ± 2.9 vs 26.6 ±13.4 minutes, P < .001). Two patients (2.5%, 2/79) experienced adverse events in the ESD group and but there were no adverse events in the UEMR group; however, this difference was not statistically significant.

CONCLUSION

UEMR is a safe and effective technique that should be considered when removing small rectal NETs. Further studies are warranted to define its role compared with ESD.

Underwater versus conventional endoscopic resection of nondiminutive nonpedunculated colorectal lesions: a prospective randomized controlled trial (with video)

BACKGROUND AND AIMS

Incomplete resection of colorectal neoplasia decreases the efficacy of colonoscopy. Conventional resection (CR) of polyps, performed in a gas-distended colon, is the current standard, but incomplete resection rates of approximately 2% to 30% for nondiminutive (>5 mm), nonpedunculated lesions are reported. Underwater resection (UR) is a novel technique. The aim of this study was to determine the incomplete resection rates of colorectal lesions removed by UR versus CR.

METHODS

In a randomized controlled trial, patients with small (6-9 mm) and large (≥10 mm) nonpedunculated lesions were assigned to CR (gas-distended lumen) or UR (water-filled, gas-excluded lumen). Small lesions in both arms were removed with a dedicated cold snare. For CR, large lesions were removed with a hot snare after submucosal injection. For UR, large lesions were removed with a hot snare without submucosal injection. Four-quadrant biopsy samples around the resection sites were used to evaluate for incomplete resection.

RESULTS

Four hundred sixty-two eligible polyps (248 UR vs 214 CR) from 255 patients were removed. Incomplete resection rates for UR and CR were low and did not differ (2% vs 1.9%, P = .91). UR was performed significantly faster for lesions ≥10 mm in size (10-19 mm, 2.9 minutes vs 5.6 minutes, P < .0001); ≥20 mm, 7.3 minutes vs 9.5 minutes, P = .015).

CONCLUSIONS

Low incomplete resection rates are achievable with UR and CR. UR is effective and safe with the advantage of faster resection and potential cost savings for removal of larger (≥10 mm) lesions by avoiding submucosal injection. As an added approach, UR has potential to improve the cost-effectiveness of colonoscopy by increasing efficiency and reducing cost while maintaining quality. (Clinical trial registration number: NCT02889679.).

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

BACKGROUND

Underwater endoscopic mucosal resection without submucosal injection (UEMR) is an appealing therapy for large colorectal polyps. However, this technique is not practiced widely and there are limited data evaluating UEMR in community settings.

METHODS

The study comprised patients undergoing UEMR of large (≥20 mm) sessile colorectal lesions at a community-based center. Residual neoplasia was assessed via follow-up colonoscopy.

RESULTS

Among 264 lesions (diameter 38 ± 18 mm; range 20-110 mm) 99% were successfully resected with UEMR. Two lesions involving the cecum/IC valve required multiple sessions. There were no cases of perforation or post-polypectomy syndrome. Delayed bleeding occurred in 1.6%, all managed conservatively. Residual neoplasia was present in 5.7% and was amenable to UEMR.

CONCLUSION

This large community-based series demonstrated high efficacy and safety of UEMR for large sessile colorectal lesions. The results support UEMR as first-line therapy for these lesions.

SUMMARY

Underwater endoscopic mucosal resection without submucosal injection (UEMR) is a recently developed method that has advantages over conventional EMR for treatment of large colorectal lesions. However, UEMR is not practiced widely and there are limited data evaluating this technique in everyday practice. This large community-based series demonstrated high efficacy and safety of UEMR for large sessile colorectal lesions.

Underwater cold snare polypectomy for colorectal adenomas

BACKGROUND AND AIM

Cold snare polypectomy (CSP) is a safe treatment for colorectal adenomas. However, the R0 resection rate is not sufficiently high because of inadequate resection of muscularis mucosa. We hypothesized that CSP in an underwater environment could improve this procedure by helping to safely achieve resection containing the muscularis mucosa. We have named this procedure underwater cold snare polypectomy (UCSP). We aimed to investigate the efficacy and safety of UCSP for colorectal adenomas.

METHODS

Between May 2017 and April 2018, patients diagnosed with colorectal adenomas <9 mm underwent UCSP. After follow-up colonoscopy 3 weeks later, the patients post-UCSP scars were biopsied. Outcomes were compared with those of a historical control group who underwent conventional CSP in our previous study using propensity score-matching methods.

RESULTS

Overall, 224 lesions in 65 patients were prospectively resected by UCSP. Pathologically, 209 lesions were adenomas (4.5 ± 1.5 mm) including one intramucosal carcinoma. Only one pathological residual adenoma was identified, but there was no significant difference in the residual rate between the UCSP and CSP groups (both 1.0%). No complications were observed. R0 resection rate and rate of area containing the muscularis mucosa in the UCSP group were significantly higher than those in the CSP group (80.2% vs 32.7%, P < 0.001; 50.0% vs 35.3%, P = 0.015).

CONCLUSION

Underwater cold snare polypectomy for diminutive and small colorectal adenomas was safe and effective from the perspective of pathological complete resection, which is likely facilitated by achieving an adequate depth of resection.

Comparison of underwater and conventional endoscopic mucosal resection for removing sessile colorectal polyps: a propensity-score matched cohort study

Background and study aims  Endoscopic mucosal resection (EMR) is a standard method for removing sessile colorectal polyps ≥ 10 mm. Recently, underwater EMR (UEMR) has been introduced as a potential alternative. However, the effectiveness and safety of UEMR compared with conventional EMR is un clear. Patients and methods  In this 1:1 propensity score (PS) matched retrospective cohort study, we compared the en bloc resection rates, procedure time, intraprocedural and delayed bleeding rates, and incidence of muscle layer injury. We also performed subgroup analyses by sizes of polyps (< 20 mm and ≥ 20 mm). Results  Among 350 polyps in 315 patients from August 2012 to November 2017, we identified 121 PS-matched pairs. Mean polyp size was 16.8 mm. With similar en bloc resection rates (EMR: 82.6 % vs. UEMR: 87.6 %, rate difference: 5.0, 95 % confidence interval [95 % CI]: - 4 to 13.9 %), UEMR demonstrated a shorter resection time (10.8 min vs. 8.6 min, difference: - 2.2 min, 95 % CI: - 4.1 to - 0.3 min) and a lower intraprocedural bleeding rate (15.7 % vs. 5.8 %, rate difference: - 9.9 %, 95 % CI: - 17.6 to - 2.2 %). Incidence of delayed bleeding and muscle layer injury were low in both groups. For polyps < 20 mm, effectiveness and safety outcomes were similar in both groups. For polyps ≥ 20 mm (42 PS-matched pairs), the UEMR group has a comparable en bloc resection rate with shorter procedure time and superior safety outcomes Conclusions  UEMR achieved an en bloc resection rate comparable to conventional EMR with less intraprocedural bleeding and a shorter procedure time.

Underwater Endoscopic Mucosal Resection

Although an established standard, conventional endoscopic mucosal resection (EMR) has disseminated despite an absence of studies demonstrating the value of submucosal injection. Several consequences of poorly executed submucosal injection may increase the difficulty and risk of EMR. Underwater EMR (UEMR), an alternative resection method for colonic neoplasms, avoids the need for submucosal injections. In comparison with reported outcomes of EMR, UEMR achieves similar rates of complete resection with comparable safety, with lower rates of recurrence and fewer repeat procedures. UEMR also compares favorably with endoscopic submucosal dissection in terms of procedure time and rates of complete resection, recurrence, and complications.

Saline-pocket endoscopic submucosal dissection for superficial colorectal neoplasms: a randomized controlled trial (with video)

BACKGROUND AND AIMS

Colorectal endoscopic submucosal dissection (ESD) is a time-consuming procedure because of the technical difficulty. The newly developed saline-pocket ESD (SP-ESD) provides a clearer view and better traction of the submucosal layer compared with the standard ESD with gas insufflation (S-ESD). This study aimed to prospectively compare the efficacy and safety between S-ESD and SP-ESD in patients with superficial colorectal neoplasms (SCNs).

METHODS

From April 2017 to November 2018, 95 patients with SCNs ≥20 mm in diameter were prospectively and randomly enrolled. Four patients were excluded because of an incomplete ESD procedure. Patients were finally allocated to 2 groups, S-ESD with 45 patients and SP-ESD with 46 patients. The primary outcome was dissection speed. Secondary outcomes were ESD procedure time, en bloc and complete resection rates, perforation rate, and adverse effects.

RESULTS

Median dissection speed was significantly faster in the SP-ESD than the S-ESD group (20.1 mm²/min [range, 17.3-28.1] vs 16.3 mm²/min [range, 11.4-19.8]; P < .001). Median procedure time was significantly shorter in the SP-ESD than the S-ESD group (29.5 minutes [range, 22.3-44] vs 41 minutes [range, 31-55]; P < .001). The en bloc and complete resection rates were 100% in both groups. No perforations occurred among patients. The volume of saline solution used in the SP-ESD group was significantly greater than that in the S-ESD group (200 mL [range, 120-250] vs 150 mL [range, 100-200]; P = .016).

CONCLUSIONS

SP-ESD improved dissection speed and procedure time compared with S-ESD. SP-ESD may be an alternative method for resection of SCNs. (Clinical trial registration number: UMIN 000026317.).

Underwater polypectomy without submucosal injection for colorectal lesions ≤ 20 mm in size-a multicenter retrospective observational study

BACKGROUND

Underwater polypectomy (UWP) of large (≥ 20 mm) colorectal lesions is well described, but reports of UWP for lesions ≤ 20 mm in size, which account for > 95% of polyps encountered in routine clinical practice, are limited. We assessed the feasibility of UWP in routine practice across various sites for colorectal lesions ≤ 20 mm in size.

METHODS

A multicenter retrospective study was performed on pooled data from nine colonoscopists at 3 U.S., 1 Taiwanese and 2 Italian sites. Outcomes related to UWP on lesions ≤ 20 mm in size were analyzed.

RESULTS

In 117 patients, UWP netted 169 lesions. Polypectomy by hot (HSP, 54%) or cold (CSP, 41%) snare, and cold forceps (CFP, 5%) were performed successfully without endoscopic evidence of residual neoplasia or immediate clinically significant adverse events. The majority (74.6%) were tubular adenomas; 60.9% were from the proximal colon. Histopathologic margins were positive in 4 and unavailable in 26 CSP and 24 HSP specimens. The remainder had negative resection margins on pathologic reports.

CONCLUSION

UWP for colorectal lesions ≤ 20 mm in routine practice across multiple sites confirms the feasibility and acceptability of this technique. Improvement of resection outcomes by UWP in routine practice deserves further evaluation in a randomized controlled trial.

Underwater EMR for colorectal lesions: a systematic review with meta-analysis (with video)

BACKGROUND AND AIMS

Underwater EMR is an alternative way to have nonpedunculated colorectal lesions lifted before being resected. The endoscopist takes advantage of the behavior of mucosal lesions floating away from the muscular layer, once immersed in liquid. We performed a systematic review with meta-analysis to evaluate the efficacy and safety of this technique.

METHODS

Electronic databases (Medline, Scopus, EMBASE) were searched up to May 2018. Full articles including patients with colorectal lesions resected by the underwater EMR technique were eligible. The complete resection (primary outcome), en bloc resection, recurrence, and adverse event rates were pooled by means of a random or fixed-effect model.

RESULTS

Ten studies were eligible, providing data on 508 lesions removed from 433 patients (male/female = 239/194; mean age range 62.2-75.0 years). Six studies were performed in the United States and the other in Europe; 7 studies were prospective. The specific indications for performing underwater EMR varied widely across studies. The complete resection rate was 96.36% (95% confidence interval [CI], 91.77-98.44), with a rate of en bloc resection of 57.07% (95% CI, 43.20%-69.91%). The recurrence rate was 8.82% (95% CI, 5.78-13.25) in a mean endoscopy surveillance period of 7.7 months (range 4-15 months). The postprocedural bleeding rate was 2.85% (95% CI, 1.64-4.90). Bleeding during the procedure was always mild and was considered as part of the procedure in all series. The overall adverse event rate was 3.31% (95% CI, 1.97%-5.52%). No cases of perforation were reported.

CONCLUSION

According to the results of this systematic review, underwater EMR appears to be an effective and extremely safe technique for resecting nonpolypoid colorectal lesions.

Serrated Lesions of the Colon-Rectum: A Focus on New Diagnostic Tools and Current Management

Prompt diagnosis and correct management of the so called "serrated lesions" (SLs) of the colon-rectum are generally considered of crucial importance in the past years, mainly due to their histological heterogeneity and peculiar clinical and molecular patterns; sometimes, they are missed at conventional endoscopy and are possibly implicated in the genesis of interval cancers. The aim of this review is to focus on the diagnostic challenges of serrated lesions, underlying the role of both conventional endoscopy and novel technologies. We will show how an accurate and precise diagnosis should immediately prompt the most appropriate therapy other than defining a proper follow-up program. It will be emphasized how novel endoscopic techniques may provide better visualization of mucosal microsurface structures other than enhancing the microvascular architecture, in order to better define and characterize specific patterns of mucosal lesions of the gastrointestinal tract. Standard therapy of SLs of the colon-rectum is still very debated, also due to the relatively lack of studies focusing on treatment issues. The high risk of incomplete resection, together with the high rate of postcolonoscopy interval cancers, suggests the need of an extra care when facing this kind of lesions. Given this background, we will outline useful technical tips and tricks in the resection of SLs, taking aspects such as the size and location of the lesions, as well as novel available techniques and technologies, other than future perspectives, including confocal laser endomicroscopy into consideration. Follow-up of SLs is another hot topic, also considering that their clinical impact has been misunderstood for a long time. The incidence of the so called interval colorectal cancer underlines how some weaknesses exist in current screening and follow-up programs. Considering the lack of wide consensus for the management of some SLs, we will try to summarize and clarify the best strategies for their optimal management.

Water-pocket endoscopic submucosal dissection for superficial gastric neoplasms (with video)

BACKGROUND AND AIMS

During endoscopic submucosal dissection (ESD), a clear view is essential for precise dissection of the appropriate submucosal layer. Some advantages have been reported for underwater techniques of endoscopic resection in comparison with the gas insufflation method. We have developed a new ESD method with the creation of a local water pocket (WP) that provides a clear view in the dissection field. Therefore, we aimed to investigate the feasibility and safety of WP-ESD for superficial gastric neoplasms.

METHODS

We prospectively recruited 50 patients with gastric neoplasms (early gastric cancer or gastric adenomas) between April 2017 and December 2017. Among them, 48 patients were treated with the WP-ESD technique. The patients undergoing WP-ESD were compared with 48 patients treated with standard ESD (S-ESD) who were selected by propensity score matching. The primary outcome was the ESD procedure time.

RESULTS

Total procedure time was significantly shorter in the WP-ESD group than in the S-ESD group (median [interquartile range], 27.5 [19-45] minutes vs 41 [29.8-69] minutes; P < .001). Similarly, the dissection speed was significantly greater in the WP-ESD group than in the S-ESD group (median [interquartile range], 22.5 [16.8-35.3] mm²/min vs 17.3 [12.7-22.1] mm²/min; P < .001). The rates of complete en bloc resection in the WP-ESD group and the S-ESD group were 97.9% and 95.8%, respectively (P > .99). There were no perforations in either group.

CONCLUSION

WP-ESD was associated with a shorter procedure time than S-ESD. WP-ESD may provide an alternative method for resection of superficial gastric neoplasms. (Clinical trial registration number: UMIN 000030266.).

Underwater endoscopic colorectal polyp resection: Feasibility in everyday clinical practice

BACKGROUND

Endoscopic mucosal resection is well-established for resecting flat or sessile benign colon polyps. The novel underwater endoscopic mucosal resection eschews submucosal injection prior to endoscopic mucosal resection. Reports about underwater endoscopic mucosal resection were limited to small series of single and/or tertiary-care referral centers, with single or supervised operators.

OBJECTIVE

The purpose of this study was to determine feasibility and efficacy of underwater resection of polyps of any morphology (underwater polypectomy, here includes underwater endoscopic mucosal resection) in routine clinical practice.

METHODS

This study involved a comparison of colonoscopy records of two community hospitals (January 2015-December 2016) for underwater polypectomy (n = 195) and gas insufflation polypectomy (n = 186).

RESULTS

Comparable demographics, procedural data, overall distribution, morphology and size of resected lesions, number of en bloc and R0 resections (any polyp morphology and size); exception: overall, underwater polypectomy pedunculated polyps were significantly larger than those in the gas insufflation polypectomy group, p = 0.030. Underwater polypectomy (median, min) resection time was significantly shorter than gas insufflation polypectomy: sessile and flat polyps 6-9 mm, 0.8 vs 2.7 (p = 0.040); 10-19 mm, 2.0 vs 3.3 (p = 0.025), respectively; pedunculated polyps 6-19 mm, 0.8 vs 3.3 (p < 0.001). Underwater polypectomy resection of pedunculated polyps 6-19 mm showed significantly less immediate bleeding: 11.1% vs 1.5%, respectively (p = 0.031).

CONCLUSIONS

Underwater polypectomy can be efficaciously used in routine clinical practice for the complete resection of colon polyps, with several advantages over gas insufflation polypectomy.

Management of Serrated Polyps of the Colon

PURPOSE OF REVIEW

The purpose of this review is to summarize the management of serrated colorectal polyps (SPs), with a particular focus on the most common premalignant SP, sessile serrated adenoma or polyp (SSA/P). These lesions present a challenge for endoscopists with respect to detection and resection, and are also susceptible to pathologic misdiagnosis.

RECENT FINDINGS

Patients with SSA/Ps are at an increased risk of future colorectal neoplasia, including advanced polyps and cancer. Reasonable benchmarks for SP detection rates are 5-7% for SSA/Ps and 10-12% for proximal SPs. Certain endoscopic techniques such as chromoendoscopy, narrow band imaging, water immersion, and wide-angle viewing may improve SSA/P detection. Emerging endoscopic techniques such as underwater polypectomy, suction pseudopolyp technique, and piecemeal cold snare polypectomy are helpful tools for the endoscopist's armamentarium for removing SSA/Ps. Proper orientation of SSA/P specimens can improve the accuracy of pathology readings. Patients with confirmed SSA/Ps and proximal HPs should undergo surveillance at intervals similar to what is recommended for patients with conventional adenomas. Patients with SSA/Ps may also be able to lower their risk of future polyps by targeting modifiable risk factors including tobacco and alcohol use and high-fat diets. NSAIDs and aspirin appear to be protective agents. SPs and SSA/Ps in particular are important colorectal cancer precursors that merit special attention to ensure adequate detection, resection, and surveillance.

Feasibility of Underwater Endoscopic Mucosal Resection for Colorectal Lesions: A Single Center Study in Japan

Background

Underwater endoscopic mucosal resection (U-EMR) has emerged as an alternative technique for the resection of colorectal lesions. This study aimed to evaluate our initial experience using U-EMR.

Methods

This is a single-center, retrospective case series study. We analyzed the clinical outcomes of consecutive patients who underwent U-EMR in our endoscopy center, from December 2015 to February 2017.

Results

Our analysis included 64 lesions, contributed by 38 patients, with a mean age of 68.6 years (range, 25 to 90 years). The study sample included 33 right-sided and 25 left-sided colon lesions, and seven rectal lesions, with an average size of 16.2 mm (6 - 40 mm). Of these, 46 lesions were polypoid and 18 ones non-polypoid. Histologically, 31 lesions were low-grade adenomas, eight ones were high-grade adenomas, 11 were mucosal cancers, four were submucosal cancers, and 10 were classified as “others”. En bloc resection was achieved in 52 (81%) lesions, with an en bloc resection rate of 95% for lesions < 20 mm and 55% for lesions ≥ 20 mm. Complete resection of neoplastic epithelial lesions, defined by a negative pathological margin, was achieved in 32 of 59 neoplastic epithelial lesions (54%). We identified three cases (5%) of post-procedural bleeding and one case of perforation (2%).

Conclusions

U-EMR can be feasibly used for resection of colonic lesions, including lesions ≥ 20 mm, although the en bloc resection rate for these lesions was lower than for lesions < 20 mm.

Feasibility and outcomes of underwater endoscopic mucosal resection for ≥ 10 mm colorectal polyps

BACKGROUND

Underwater endoscopic mucosal resection (UEMR) is an emerging strategy for the management of colorectal polyps. We aimed to evaluate the efficacy and safety of UEMR for clinically significant (≥ 10 mm) colorectal polyps.

METHODS

We performed a prospective dual-centre study of polyps ≥ 10 mm undergoing UEMR between June 2014 and March 2017. Outcomes measured comprised: (1) completeness of resection at index UEMR, (2) intraprocedural and 30-day complications, (3) rates and predictors of submucosal lift, en bloc resection, polyp/adenoma recurrence and (4) pain score. Endoscopy records were correlated with histology.

RESULTS

85 patients underwent UEMR of 97 polyps. Resection was endoscopically complete at index UEMR in 97.9%. The median pain score was 0 (no pain). Submucosal lift was required in 29.9% and correlated with polyp size ≥ 30 mm (p = 0.03) and clip placement (p = 0.004). En bloc resection was achieved in 45.4%, and inversely correlated with polyp size ≥ 20 mm (p < 0.001). 30-day complications (4.1%) were minor and consisted of intraprocedural bleeding (n = 2) and delayed bleeding (n = 2). 60.8% attended endoscopy post-UEMR after a median interval of 6 months, with 20.3% polyp and 13.6% adenoma recurrence. Polyp recurrence was associated with piecemeal resection (p = 0.04), recurrent polyp (p = 0.02), female sex (p = 0.01) and poor access (p = 0.005). Predictors for adenoma recurrence included female gender (p = 0.01) and difficult access (p < 0.001). Recurrence rates did not differ with polyp size, site, morphology, dysplasia status, submucosal injection, patient age, or study centre.

CONCLUSIONS

UEMR is an effective, safe and well tolerated option for significant colorectal polyps. Piecemeal resection, recurrent polyp, female gender, and difficult access are predictors of post-UEMR polyp recurrence.

Colorectal endoscopic mucosal resection (EMR)

Colonoscopy has the benefit of detecting and treating precancerous adenomatous polyps and thus reduces mortality associated with CRC. Screening colonoscopy is the keystone for prevention of colorectal cancer. Over the last 20 years there has been increased in the management of large colorectal polyps from surgery to endoscopic removal techniques which is less invasive. Traditionally surgical resection was the treatment of choice for many years for larger polyps but colectomy poses significant morbidity of 14-46% and mortality of up to 7%. There are several advantages of endoscopic resection technique over surgery; it is less invasive, less expensive, has rapid recovery, and preserves the normal gut functions. In addition patient satisfaction and efficacy of EMR is higher with minor complications. Thus, this has facilitated the development of advanced resection technique for the treatment of large colorectal polyps called as endoscopic mucosal resection (EMR).

Underwater endoscopic mucosal resection is associated with fewer recurrences and earlier curative resections compared to conventional endoscopic mucosal resection for large colorectal polyps

BACKGROUND

Studies comparing the efficacy and safety of conventional saline-assisted piecemeal endoscopic mucosal resection (EMR) to underwater EMR (UEMR) without submucosal lifting of colorectal polyps are lacking. The objective of this study was to compare the efficacy and safety of EMR to UEMR of large colorectal polyps.

METHODS

Two hundred eighty-nine colorectal polyps were removed by a single endoscopist from 7/2007 to 2/2015 using EMR or UEMR. 135 polyps (EMR: 62, UEMR: 73) that measured ≥15 mm and had not undergone prior attempted polypectomy were evaluated for rates of complete macroscopic resection and adverse events. 101 of these polyps (EMR: 46, UEMR: 55) had at least 1 follow-up colonoscopy and were studied for rates of recurrence and the number of procedures required to achieve curative resection.

RESULTS

The rate of complete macroscopic resection was higher following UEMR compared to EMR (98.6 vs. 87.1%, p = 0.012). UEMR had a lower recurrence rate at the first follow-up colonoscopy compared to EMR (7.3 vs. 28.3%, OR 5.0 for post-EMR recurrence, 95% CI: [1.5, 16.5], p = 0.008). UEMR required fewer procedures to reach curative resection than EMR (mean of 1.0 vs. 1.3, p = 0.002). There was no significant difference in rates of adverse events.

CONCLUSIONS

UEMR appears superior to EMR for the removal of large colorectal polyps in terms of rates of complete macroscopic resection and recurrent (or residual) abnormal tissue. Compared to conventional EMR, UEMR may offer increased procedural effectiveness without compromising safety in the removal of large colorectal polyps without prior attempted resection.

Evaluation and long-term outcomes of the different modalities used in colonic endoscopic mucosal resection

Endoscopic mucosal resection (EMR) has been used in western countries to remove colonic polyps for at least the last two decades. Significant experience has been accumulated and the efficacy of the method has recently been evaluated in a large meta-analysis. A number of variations to modify the technique, including knife-assisted, cap-assisted, ligation devices, and underwater EMR, have been developed in an attempt to improve outcomes. However, to date there are only limited data comparing these techniques or demonstrating the superiority of any one of them. This article reviews the current evidence on the efficacy of each of these modified techniques.