Large Non-pedunculated Colorectal Polyps Research Articles

Cold versus Hot Snare Endoscopic Resection of Large Non-Pedunculated Colorectal Polyps (Randomized-controlled German CHRONICLE-trial)

Endoscopic mucosal resection (EMR) is standard therapy for non-pedunculated colorectal polyps ≥20mm. Recently, it has been suggested that polyp resection without current (cold resection) may be superior to the standard technique using cutting/coagulation current (hot resection) by reducing adverse events (AE), but evidence from a randomized trial is missing. In this randomized-controlled multicentric trial involving 19 centers, non-pedunculated colorectal polyps ≥20mm were randomly assigned to cold or hot EMR. Primary outcome was major AE (perforation or post-endoscopic bleeding). Among secondary outcomes major AE subcategories, postpolypectomy-syndrome and residual adenoma were most relevant. Between 2021 and 2023, 396 polyps in 363 patients (48.2% female) were enrolled for the intention-to-treat analysis. Major AE occurred in 1.0 % in the cold and in 7.9% in the hot group (p=0.001; Odds ratio [OR] 0.12 [95%-CI: 0.03-0.54]). Rates for perforation and post-endoscopic bleeding were significantly lower in the cold group with 0% vs. 3.9% (p=0.007) and 1.0% vs. 4.4% (p=0.040). Postpolypectomy-syndrome occurred with similar frequency (3.1% vs. 4.4%, p=0.490). After cold resection, residual adenoma was found more frequently, with 23.7% vs. 13.8% (p=0.020; OR 1.94 [95%-CI: 1.12-3.38]). In multivariable analysis, lesion diameter of ≥4cm was an independent predictor both for major AE (OR 3.37) and residual adenoma (OR 2.47), and high-grade dysplasia/cancer for residual adenoma (OR 2.92). Cold resection of large non-pedunculated colorectal polyps appears considerably safer than hot EMR, however at the cost of a higher residual adenoma rate. Further studies have to confirm to which extent polyp size and histology can determine an individualized approach (Trial number: DRKS00025170).

Standardised training for endoscopic mucosal resection of large non-pedunculated colorectal polyps to reduce recurrence (*STAR-LNPCP study): a multicentre cluster randomised trial

ObjectiveEndoscopic mucosal resection (EMR) is the preferred treatment for non-invasive large (≥20 mm) non-pedunculated colorectal polyps (LNPCPs) but is associated with an early recurrence rate of up to 30%. We...

A94 PRE-RESECTION OPTICAL EVALUATION RELIABLY DIFFERENTIATES BETWEEN SERRATED AND ADENOMATOUS LARGE NON-PEDUNCULATED COLORECTAL POLYPS

Abstract Background Modality selection between cold snare resection (CSR) and endoscopic mucosal resection (EMR) or endoscopic submucosal dissection (ESD) is largely predicated on the ability to differentiate between serrated and adenomatous histopathology. While optical evaluation has modest accuracy for diminutive polyps, performance has not been evaluated for large non-pedunculated colorectal polyps (LNPCPs). Aims To evaluate the performance of pre-resection optical evaluation to differentiate between serrated and adenomatous LNPCPs. Methods Consecutive patients ampersand:003E 18 years of age who underwent endoscopic resection for a LNPCP were enrolled in a prospective single center observation cohort study (clinicaltrials.gov ID: NCT05402696). Pre-resection optical evaluation was performed using high-definition white-light and narrow-band imaging (NBI) with or without near-focus. The Japanese NBI Expert Team (JNET) classification was used to differentiate between serrated (JNET I) vs. adenomatous (JNET IIA, IIB) LNPCPs. Traditional serrated adenomas (TSAs) and cancers were excluded from analysis. Sensitivity, specificity, and accuracy were used to evaluate optical evaluation performance. Results From 06/2022-09/2023, 266 patients underwent 282 procedures for a total of 335 LNPCPs. Median size was 30mm (IQR 20-40mm). Histopathology identified 215 (64.2%) adenomatous, 91 (27.2%) serrated, 16 (4.8%) cancerous, and 13 (3.9%) other LNPCPs; including 5 TSAs. Of the 91 serrated lesions, 90 (98.9%) were predicted as serrated; sensitivity, specificity, and accuracy were 98.90% (95% CI 94.03-99.97), 99.53% (95% CI 97.44-99.99), 99.35% (95% CI 97.66-99.92), respectively. Of the 215 adenomatous lesions, 213 (99.1%) were predicted as adenomatous; sensitivity, specificity, and accuracy were 99.07% (95% CI 96.68-99.89), 98.90% (95% CI 94.03-99.97), 99.02% (95% CI 97.16-99.80), respectively. Conclusions Optical evaluation demonstrates excellent performance characteristics to differentiate between serrated and adenomatous LNPCPs; therefore, empowering endoscopists to reliably apply a selective resection algorithm between CSR, EMR and ESD. Funding Agencies None

A119 ACUTE COLONOC PSEUDO-OBSTRUCTION AFTER ENDOSCOPIC RESECTION OF A FULLY CIRCUMFERENTIAL LARGE NON-PEDUNCULATED COLORECTAL POLYP

Abstract Background Complex large non-pedunculated colorectal polyps (LNPCPs), including those involving the full circumference of the bowel, are now readily managed by minimally invasive endoscopic resection techniques. Established procedure-related adverse events include sedation related adverse events, deep mural injury, clinically significant post-resection bleeding, delayed perforation and serositis. An appreciation for potential procedure-related adverse events is critical to the effective implementation of these techniques. Aims To describe a case of acute colonic pseudo-obstruction after endoscopic resection of a fully circumferential LNPCP. Methods Case report and review of the literature Results A 91-year-old male with a history of atrial fibrillation, chronic kidney disease and suspected McKittrick-Wheelock syndrome underwent successful endoscopic mucosal resection (EMR) of a 100mm fully circumferential LNPCP in the sigmoid colon. Histopathology diagnosed a tubulovillous adenoma with high-grade dysplasia. After elective admission, he suffered from clinically significant post-EMR bleeding requiring 2 units of packed red blood cells. On post-operative day 1 he began to suffer from nausea, abdominal pain and obstipation. On examination, he was visibly distended. Abdominal X-ray revealed extensive gas-filled loops of small and large bowel with the absence of gas in the rectum. He was managed conservatively with nasogastric tube decompression. Total duration of hospital stay was 9 days. Conclusions Critical to the continued expansion of minimally invasive endoscopic resection techniques is an awareness for potential procedure-related adverse events. To our knowledge this is the first description of acute colonic pseudo-obstruction after endoscopic resection Funding Agencies None

Establishment of Standards for the Referral of Large Non-Pedunculated Colorectal Polyps: An International Expert Consensus Using a Modified Delphi Process

Establishment of Standards for the Referral of Large Non-Pedunculated Colorectal Polyps: An International Expert Consensus Using a Modified Delphi Process

Safety and efficacy of physician-administered balanced-sedation for the endoscopic mucosal resection of large non-pedunculated colorectal polyps.

Background and study aims Because of concerns about peri-procedural adverse events (AEs), guidelines recommend anesthetist-managed sedation (AMS) for long and complex endoscopic procedures. The safety and efficacy of physician-administered balanced sedation (PA-BS) for endoscopic mucosal resection (EMR) of large non-pedunculated colorectal polyps (LNPCPs) ≥20 mm is unknown. Patients and methods We compared PA-BS with AMS in a retrospective study of prospectively collected data from consecutive patients referred for management of LNPCPs (NCT01368289; NCT02000141). A per-patient propensity analysis was performed following a 1:2 nearest-neighbor (Greedy-type) match, based on age, gender, Charlson comorbidity index, and lesion size. The primary outcome was any peri-procedural AE, which included hypotension, hypertension, tachycardia, bradycardia, hypoxia, and new arrhythmia. Secondary outcomes were unplanned admissions, 28-day re-presentation, technical success, and recurrence. Results Between January 2016 and June 2020, 700 patients underwent EMR for LNPCPs, of whom 638 received PA-BS. Among them, the median age was 70 years (interquartile range [IQR] 62-76 years), size 35 mm (IQR 25-45 mm), and duration 35 minutes (IQR 25-60 minutes). Peri-procedural AEs occurred in 149 (23.4%), most commonly bradycardia (116; 18.2%). Only five (0.8%) required an unplanned sedation-related admission due to AEs (2 hypotension, 1 arrhythmia, 1 bradycardia, 1 hypoxia), with a median inpatient stay of 1 day (IQR 1-3 days). After propensity-score matching, there were no differences between PA-BS and AMS in peri-procedural AEs, unplanned admissions, 28-day re-presentation rates, technical success or recurrence. Conclusions Physician-administered balanced sedation for the EMR of LNPCPs is safe. Peri-procedural AEs are infrequent, transient, rarely require admission (<1%), and are experienced in similar frequencies to those receiving anesthetist-managed sedation.

Endoscopic resection of large anastomotic polyps is safe and effective.

Large (≥20mm) adenomatous anastomotic polyps (LAAPs) are uncommon. Data pertaining to their prevalence, characteristics, and the efficacy of endoscopic resection (ER) are absent. A safe and effective strategy for ER would reduce morbidity and healthcare costs. Large nonpedunculated colorectal polyps of ≥20mm (LNPCPs) referred for ER were prospectively studied. Multiple data points were recorded including anastomotic location, polyp morphology, resection modality, complications, and technical success. Over 7 years until November 2022, 2629 lesions were referred. Of these, 10 (0.4%) were LAAPs (median size 35 mm [interquartile range (IQR) 30-40mm]). All LAAPs were removed by piecemeal endoscopic mucosal resection (EMR), most (n=9; 90%) in combination with cold-forceps avulsion with adjuvant snare-tip soft coagulation (CAST). On comparison of the LAAP group with the conventional LNPCP group, CAST was more commonly used (90% vs. 9%; P<0.001) and deep mural injury (DMI) type II was more frequent (40% vs. 11%, P=0.003); however, significant DMI (III-V) did not occur. At 6 month (IQR 5.25-6 months) surveillance, there was no recurrence in any of the 10 cases. There were no serious adverse events. LAAPs present unique challenges owing to their location overlying an anastomosis. Despite these challenges they can be safely and effectively managed endoscopically without recurrence at endoscopic follow-up.

Comments on: "Effect of pre-resection biopsy on detection of advanced dysplasia in large nonpedunculated colorectal polyps undergoing endoscopic mucosal resection".

Comments on: "Effect of pre-resection biopsy on detection of advanced dysplasia in large nonpedunculated colorectal polyps undergoing endoscopic mucosal resection".

Endoscopic Management of Large Non-Pedunculated Colorectal Polyps.

Large non-pedunculated colorectal polyps ≥20 mm (LNPCPs) comprise approximately 1% of all colorectal polyps. LNPCPs more commonly contain high-grade dysplasia, covert and overt cancer. These lesions can be resected using several means, including conventional endoscopic mucosal resection (EMR), cold-snare EMR (C-EMR) and endoscopic submucosal dissection (ESD). This review aimed to provide a comprehensive, critical and objective analysis of ER techniques. Evidence-based, selective resection algorithms should be used when choosing the most appropriate technique to ensure the safe and effective removal of LNPCPs. Due to its enhanced safety and comparable efficacy, there has been a paradigm shift towards cold-snare polypectomy (CSP) for the removal of small polyps (<10 mm). This technique is now being applied to the management of LNPCPs; however, further research is required to define the optimal LNPCP subtypes to target and the viable upper size limit. Adjuvant techniques, such as thermal ablation of the resection margin, significantly reduce recurrence risk. Bleeding risk can be mitigated using through-the-scope clips to close defects in the right colon. Endoscopic surveillance is important to detect recurrence and synchronous lesions. Recurrence can be readily managed using an endoscopic approach.

Can we stop routine biopsy of post-endoscopic mucosal resection scars?

Endoscopic mucosal resection (EMR) is internationally accepted as the gold standard, first-line intervention for large nonpedunculated colorectal polyps. The technique has been incrementally refined over the past decade to allow safe and effective removal of large nonpedunculated colorectal polyps in all areas of the colon, including challenging locations such as the anorectal junction or ileocecal valve. Safety issues have been addressed with techniques to reduce the risks of clinically significant post-EMR bleeding and deep mural injury. Outcomes have also been improved with strategies to detect and predict submucosal invasion so that the optimum resection approach can be chosen [1].

Need for adjunctive removal techniques for endoscopic mucosal resection of large non-pedunculated colonic polyps is predictive of recurrence

Abstract Background and study aims Endoscopic mucosal resection (EMR) allows for safe and effective removal of large non-pedunculated colon polyps, but recurrence remains a significant concern. Risk factors for recurrence have previously been reported, however, the significance of these factors have varied and has uncertain applicability with recent advances in EMR techniques. We aimed to evaluate rates and risk factors for recurrence in recent years from a major Canadian referral center. Patients and methods Consecutive patients between April 1, 2017 and March 1, 2019 who underwent piecemeal EMR were retrospectively identified. Patients with non-pedunculated colorectal polyps ≥ 2 cm removed by piecemeal EMR with available follow-up data were included. Results Five hundred and seventeen patients were reviewed, with 265 patients satisfying inclusion criteria. The median age was 67 years (IQR 14); 48 % were female. 15 % had a recurrence on follow-up endoscopy. Adjunctive removal techniques were utilized in 31 % of patients, 95 % of which was hot avulsion. The use of adjunctive removal techniques (OR 2.87, P = 0.004) and male gender (OR 3.31, P = 0.003) was significantly predictive of recurrence on multivariate analysis. Receiver operating curve characteristics demonstrated good performance of these factors in predicting recurrence (area under the curve = 0.70). Conclusions The use of adjunctive removal techniques, particularly hot avulsion and male gender are predictive of recurrence after piecemeal EMR of large non-pedunculated colorectal polyps. Male patients and those who require hot avulsion may be considered high risk for recurrence and warrant closer follow-up.

Effect of pre-resection biopsy on detection of advanced dysplasia in large nonpedunculated colorectal polyps undergoing endoscopic mucosal resection.

BACKGROUND : Pre-resection biopsy (PRB) of large nonpedunculated colorectal polyps (LNPCPs, ≥ 20 mm) is often performed before referral for endoscopic mucosal resection (EMR). How this affects the EMR procedure is unknown. METHODS : This was a retrospective analysis of a prospectively collected cohort of patients with LNPCPs referred for EMR between 2013 to 2016 at an Australian tertiary center. Outcomes were differences between PRB and EMR histology, and effects of PRB on the EMR procedure. RESULTS: Among 586 LNPCPs, lesions that underwent PRB were larger (median 35 vs. 30 mm; P < 0.007), and more commonly morphologically flat or slightly elevated (P = 0.01) compared with lesions without PRB. PRB histology was upstaged in 26.1 %, downstaged in 13.8 %, and unchanged in 60.1 % after EMR. Sensitivity of PRB was 77.2 % (95 %CI 71.1-82.4) for low grade dysplasia (LGD) and 21.2 % (95 %CI 11.5-35.1) for high grade dysplasia (HGD). Where EMR specimen showed HGD, PRB had detected LGD in 76.9 %. Where EMR specimen showed cancer, PRB had detected dysplasia only. PRB was associated with more submucosal fibrosis (P = 0.001) and intraprocedural bleeding (P = 0.03). EMR success or recurrence was not affected. CONCLUSIONS: Routine PRB of LNPCP did not reliably detect advanced histology and may have affected EMR complexity. PRB should be utilized with caution in guiding endoscopic management of LNPCPs.

Thermal ablation of mucosal defect margins to prevent local recurrence of large colorectal polyps: a systematic review and meta-analysis.

Background and study aims Endoscopic mucosal resection of large non-pedunculated colorectal polyps is characterized by a high risk of recurrence. Thermal ablation of the mucosal defect margins may reduce recurrence in these lesions, but a systematic overview of the current evidence is lacking. Methods We searched PubMed, Embase and Cochrane until July 2021, for studies on thermal ablation of mucosal defect margins of large non-pedunculated colorectal polyps. Main goal of this meta-analysis was to identify pooled risk difference of recurrence between thermal ablation vs. no adjuvant treatment. Secondary goal was to identify pooled recurrence rate after snare tip soft coagulation (STSC) and argon plasma coagulation (APC). Results Ten studies on thermal ablation of mucosal defect margins were included, with three studies on argon plasma coagulation, six studies on snare tip soft coagulation and one study comparing both treatment modalities, representing a total of 316 APC cases and 1598 STSC cases. Overall pooled risk difference of recurrence was –0.17 (95 % confidence interval [CI] –0.22 to –0.12) as compared to no adjuvant treatment. Pooled risk difference was –0.16 (95 % CI –0.19 to –0.14) for STSC and –0.26 (95 % CI –0.80 to 0.28) for APC. Pooled recurrence rate was 4 % (95 % CI 2 % to 8 %) for STSC and 9 % (95 % CI 4 % to 19 %) for APC. Conclusions Thermal ablation of mucosal defect margins significantly reduces recurrence rate in large non-pedunculated colorectal lesions compared to no adjuvant treatment. While no evidence for superiority exists, STSC may be preferred over APC, because this method is the most evidence-based, and cost-effective modality.

EMR combined with hybrid argon plasma coagulation to prevent recurrence of large nonpedunculated colorectal polyps (with videos)

EMR is the mainstay of therapy for large colorectal polyps. Local recurrence after EMR is common and can be reduced using margin ablation. Our aim was to evaluate recurrence rates when using hybrid argon plasma coagulation (h-APC) ablation after EMR. Adult patients (aged 18-89 years) undergoing EMR of nonpedunculated colorectal polyps≥20mm were enrolled in a prospective multicenter study. h-APC was used to ablate all defect margins and also the resection surface in selected cases. The primary study outcome was recurrence rates found during the first follow-up colonoscopy. Secondary outcomes were technical success and adverse event rates. EMR with h-APC ablation was used in 101 polyps (84 patients, 46.4% women). EMR with h-APC ablation was technically successful in all cases (median EMR time, 15 minutes; median h-APC ablation time, 4 minutes). Median polyp size was 30mm (range, 20-60). Resected polyps were either adenomas (68/101 [67.3%]), sessile serrated lesions (27/101 [27%]), or adenocarcinomas (6/101 [6%]). The post-EMR recurrence rate was 2.2% (2/91) (95% confidence interval, .27-7.71). All 6 patients with cancer (intramucosal cancer, 4; T1sm cancer, 2) were found to have complete eradication of the primary tumor after EMR with h-APC, and none had lymph node metastasis. Four serious adverse events occurred in 3 patients (2 delayed bleeding [2.4%], 1 abdominal pain [1.2%], and 1 microperforation [1.2%]. All serious adverse events resolved with either endoscopic or antibiotic treatment only. EMR with h-APC showed a high technical success rate, low adverse event rate, and very low post-EMR recurrence rates. (Clinical trial registration number: NCT04015765.).

Oncological outcomes after piecemeal endoscopic mucosal resection of large non-pedunculated colorectal polyps with covert submucosal invasive cancer

ObjectiveManagement of covert submucosal invasive cancer (SMIC) discovered after piecemeal endoscopic mucosal resection (pEMR) of large (>20 mm) non-pedunculated colorectal polyps is challenging. The residual cancer risk is largely unknown....

Comparison of the morphology and histopathology of large nonpedunculated colorectal polyps in the rectum and colon: implications for endoscopic treatment

The risk of cancer in large nonpedunculated colorectal polyps≥20mm (LNPCPs) in the rectum relative to the remainder of the colon is unknown. We aimed to describe differences between rectal and colonic LNPCPs to better inform treatment decisions. Patients with LNPCPs referred to tertiary centers for endoscopic resection within a prospective, multicenter, observational cohort were evaluated. Data recorded were participant demographics, LNPCP location, morphology, resection modality, and histopathologic data. Multiple logistic regression analysis was used to identify those variables independently associated with rectal versus nonrectal location in the colon. Patients with LNPCPs referred for endoscopic resection between July 2008 and July 2021 were included. Rectal LNPCPs (n= 618) were larger (median size, 40mm vs 30mm; P< .001) and more likely to be granular (79% vs 50%, P< .001) with a nodular component (53% vs 17%, P< .001) compared with nonrectal LNPCPs (n= 2787). Rectal LNPCPs were more likely to have tubulovillous histopathology (72% vs 47%, P< .001) and contain cancer (15% vs 6%, P< .001). After adjusting for the other features independently associated with location, cancer was more common in the rectum compared with the colon (odds ratio, 1.77; 95% confidence interval, 1.25-2.53). This study suggests that compared with LNPCPs in the rest of the colon, rectal LNPCPs are more likely to be larger and contain more advanced pathology. These findings have implications for curative endoscopic resection techniques particularly where early cancer is present. (Clinical trial registration numbers: NCT01368289 and NCT02000141.).

A126 ONCE IS BY CHANCE, TWO IS A TREND: A RECURRING FINDING WITHIN THE POST-RESECTION DEFECT

Abstract Background A 74-year-old male was referred for the management of a large non-pedunculated colorectal polyp in the transverse colon. On optical evaluation, including high-definition white-light and narrow-band imaging (NBI), a 30mm 0-IIA non-granular large non-pedunculated colorectal polyps (LNPCP) was identified with optical features in keeping with adenomatous histopathology (NBI International Colorectal Endoscopic II, Japan NBI Expert Team IIA, Kudo Pit Pattern III/IV). Endoscopic mucosal resection (EMR) was performed. During sequential tissue transection and evaluation of the expanding submucosal defect a hole with a surrounding white-cautery ring was identified in keeping with significant deep mural injury. However, on careful evaluation a cystic structure was identified with a viscous amorphous substance emanating from it. Endoscopic resection of the lesion was completed with subsequent through-the-scope mechanical clip closure of the area of concern. Aims case report showing unique finding of intra-cellular mucin emanating from the post-resection defect has been identified as a potential intra-procedural finding of a mucinous adenocarcinoma Methods Endoscopic mucosal resection of a mid transverse colon polyp Results Histopathology identified a villous adenoma with high-grade dysplasia with submucosal mucin and an indeterminate focus of carcinoma; highly suspicious for a mucinous adenocarcinoma. No muscularis propria was identified. After multi-disciplinary review, the patient underwent laparoscopic right hemicolectomy with no evidence of invasive disease. Conclusions Recently coined as the “fish-eye” polypectomy defect, intra-cellular mucin emanating from the post-resection defect has been identified as a potential intra-procedural finding of a mucinous adenocarcinoma; specifically, in an otherwise benign appearing LNPCP based on real-time optical evaluation. Herein we describe the second case in the literature. This reinforces the importance of meticulous evaluation of the post-resection defect to stratify this finding from deep mural injury. Moreover, further understanding of the clinical ramifications of this unique intra-procedural finding is needed. Funding Agencies None

Incremental benefit of dye-based chromoendoscopy to predict the risk of submucosal invasive cancer in large nonpedunculated colorectal polyps

Detailed lesion assessment of large nonpedunculated colorectal polyps (LNPCPs;≥20mm) can help predict the risk of submucosal invasive cancer (SMIC). Traditionally this has required the use of dye-based chromoendoscopy (DBC). We sought to assess the accuracy and incremental benefit of DBC in addition to high-definition white-light imaging (HDWLI) and virtual chromoendoscopy (VCE) for the prediction of SMIC within LNPCPs. A prospective observational study of consecutive LNPCPs at a single tertiary referral center was performed. Before resection all lesions were assessed for the presence of a demarcated area (DA), defined as an area of disordered pit or microvascular pattern, by 2 trained endoscopists before and after DBC. Diagnostic performance characteristics were calculated with histology as the reference criterion standard, and overall agreement was calculated using the κ statistic. Over 39 months to March 2021, 400 consecutive LNPCPs (median lesion size, 35mm; interquartile range, 25-45) were analyzed. The overall rate of SMIC was 6.5%. Presence of a DA had an accuracy of 91% (95% confidence interval, 87.7-93.5) for SMIC, independent of the use of DBC. The rate of interobserver agreement for presence of a DA using HDWLI+ VCE was very high (κ= .96) with no benefit gained by the addition of DBC. The use of HDWLI and VCE is likely to be adequate for lesion assessment for the prediction of SMIC among LNPCPs. Further, the absence of a DA is strongly predictive for the absence of SMIC, independent to the use of DBC. (Clinical trial registration number: NCT03506321.).

Margin marking before colorectal endoscopic mucosal resection and its impact on neoplasia recurrence (with video)

Ablation of resection margins after EMR of large nonpedunculated colorectal polyps decreases recurrence. Margin marking before EMR (EMR-MM) may represent an alternative method to achieve a healthy resection margin. We aimed to determine the efficacy of EMR-MM in reducing neoplasia recurrence. We conducted a single-center historical control study of EMR cases (EMR-MM vs conventional EMR) for nonpedunculated polyps≥20mm between 2016 and 2021. For EMR-MM, cautery marks were placed along the lateral margins of the polyp with the snare tip. EMR was then performed to include resection of the healthy mucosa containing the marks. We compared recurrence at surveillance colonoscopy after EMR-MM versus historical control subjects. Multivariable logistic regression was performed to identify factors associated with recurrence. Two hundred ten patients with 210 polyps (median size, 30mm; interquartile range: 25-40) underwent EMR-MM (n= 74) or conventional EMR (n= 136). Patient and lesion characteristics were similar between the groups. At a median follow-up of 6 months, the recurrence rate was lower with EMR-MM (6/74; 8%) compared with historical control subjects (39/136; 29%) (P< .001). EMR-MM was not associated with an increased rate of adverse events. On multivariable analysis, EMR-MM remained the strongest predictor of recurrence (odds ratio, .20; 95% confidence interval, .13-.64; P= .003) aside from polyp size (odds ratio, 2.81; 95% confidence interval, 1.35-6.01; P= .008). In this single-center historical control study, EMR-MM of large nonpedunculated colorectal polyps reduced the recurrence risk by 80% when compared with conventional EMR. This simple technique may provide an alternative to margin ablation.

Effect of prophylactic endoscopic clip placement on clinically significant post-endoscopic mucosal resection bleeding in the right colon: a single-centre, randomised controlled trial

Endoscopic mucosal resection (EMR) is a cornerstone in the management of large (≥20 mm) non-pedunculated colorectal polyps. Clinically significant post-EMR bleeding occurs in 7% of cases and is most frequently encountered in the right colon. We aimed to assess the use of prophylactic clip closure in preventing clinically significant post-EMR bleeding within the right colon. We conducted a randomised controlled trial at a tertiary centre in Australia. Patients referred for the EMR of large non-pedunculated colorectal polyps in the right colon were eligible. Patients were randomly assigned (1:1) into the clip or control (no clip) group, using a computerised random-number generator. The primary endpoint was clinically significant post-EMR bleeding, defined as haematochezia necessitating emergency department presentation, hospitalisation, or re-intervention within 14 days post-EMR, which was analysed on the basis of intention-to-treat principles. The trial is registered with ClinicalTrials.gov, NCT02196649, and has been completed. Between Feb 4, 2016, and Dec 15, 2020, 231 patients were randomly assigned: 118 to the clip group and 113 to the control group. In the intention-to-treat analysis, clinically significant post-EMR bleeding was less frequent in the clip group than in the control group (four [3·4%] of 118 patients vs 12 [10·6%] of 113; p=0·031; absolute risk reduction 7·2% [95% CI 0·7-13·8]; number needed to treat 13·9). There were no differences between groups in adverse events, including delayed perforation (one [<1%] in the clip group vs one [<1%] in the control group) and post-EMR pain (four [3%] vs six [5%]). No deaths were reported. Prophylactic clip closure can be performed following the EMR of large non-pedunculated colorectal polyps of 20 mm or larger in the right colon to reduce the risk of clinically significant post-EMR bleeding. None.