Incomplete Mucosal Layer Excision during Endoscopic Mucosal Resection: a potential source of recurrent adenoma.

BACKGROUND AND AIMS: Residual or recurrent adenoma detected during surveillance (RRA) is the major limitation of endoscopic mucosal resection (EMR). The pathogenesis of RRA is unknown although thermal ablation of the post-EMR defect (PED) margin reduces RRA. We aimed to identify a feature within the PED which could be associated with RRA. METHODS: Between 1/2017 and 7/2020 detailed prospective procedural data on all EMR procedures performed at a single centre were retrospectively analysed. At the completion of EMR the PED was systematically examined for features of incomplete mucosal layer excision (IME). This was defined as a demarcated area within the PED bordered by a white electrocautery ring, containing endoscopically identifiable features suggesting incomplete resection of the mucosa including lacy capillaries and/or visible fibres of the muscularis mucosae. Areas of IME were re-injected and re-excised by snare and submitted separately for blinded specialist gastrointestinal pathologist review. RESULTS: EMR was performed for 508 large non-pedunculated colorectal polyps (LNPCPs) (median size 35mm). In 10 PED (2.0%) an area of IME was identified and excised. Histopathological examination of areas of suspected IME demonstrated muscularis mucosae in 9/10 (90%), residual lamina propria in 9/10 (90.0%) and residual adenoma in 5/10 (50.0%). No RRA was detected during follow-up after re-excision of IME. CONCLUSION: We report the novel finding of IME within the PED after EMR of LNPCPs. IME may contain microscopic residual adenoma and therefore is a risk for RRA during follow-up. After completion of EMR the PED should be carefully evaluated and if IME is found it should be excised.

Long-term outcomes after endoscopic submucosal dissection for relative indication early gastric cancer in nonsurgical candidates.

BACKGROUND AND AIMS: Endoscopic submucosal dissection (ESD) is effective in treating early gastric cancer (EGC). Its role in patients with comorbidities along with more advanced disease is unknown. We sought to evaluate this in a large Western cohort. METHODS: Consecutive patients who underwent ESD for EGC in a single tertiary Western endoscopy center over 10 years were prospectively analyzed. The primary outcomes were long-term overall survival (OS) and disease-free survival (DFS) up to 5 years. Secondary outcomes were efficacy and serious adverse events (SAEs). RESULTS: ESD for 157 cases of EGC in 149 patients was performed in an elderly and comorbid cohort with a mean age of 73.7 years and age-adjusted Charlson Comorbidity Index of 4.2. Over a median follow-up of 51.6 months, no significant differences were found in 5-year OS (88.9% vs 77.9%, P = .290) and DFS (83.2% vs 75.1%, P = .593) between absolute indication (AI) EGC and relative indication (RI) EGC. The AI EGC cohort achieved higher en-bloc (96.3% vs 87.5%, P = .069) and R0 resection rates (93.6% vs 62.5%, P < .001) when compared with RI EGC. No significant differences were found in SAEs (7.3% vs 12.5%, P = .363). No mortality or surgical resection ensued from adverse events from ESD. CONCLUSIONS: ESD safely confers DFS in poor surgical candidates with RI EGC in a large Western cohort. Patients who are elderly and/or with comorbidities or decline surgical resection may benefit from ESD and avoid the risks of surgery and its long-term sequelae. (Clinical trial registration number: NCT02306707.).

When less is more: lower esophageal sphincter-preserving peroral endoscopic myotomy is effective for non-achalasia esophageal motility disorders.

BACKGROUND: Non-achalasia esophageal motility disorders (NAEMDs), encompassing distal esophageal spasm (DES) and hypercontractile esophagus (HCE), are rare conditions. Peroral endoscopic myotomy (POEM) is a promising treatment option. In NAEMDs, unlike with achalasia, the lower esophageal sphincter (LES) functions normally, suggesting the potential of LES preservation during POEM. METHODS: This retrospective two-center observational study focused on patients undergoing LES-preserving POEM (LES-POEM) for NAEMD. Eckardt scores were assessed pre-POEM and at 6, 12, and 24 months post-POEM, with follow-up endoscopy at 6 months to evaluate for reflux esophagitis. Clinical success, defined as an Eckardt score ≤3, served as the primary outcome. RESULTS: 227 patients were recruited over 84 months until May 2021. Of these, 16 underwent LES-POEM for an NAEMD (9 with HCE and 7 with DES). The median pre-POEM Eckardt score was 6.0 (interquartile range [IQR] 5.0-7.0), which decreased to 1.0 (IQR 0.0-1.8; P<0.001) 6 months post-POEM. This was sustained at 24 months, with an Eckardt score of 1.0 (IQR 0.0-1.8; P<0.001). Two patients (12.5%) developed Los Angeles grade A or B esophagitis. CONCLUSIONS: LES-POEM for NAEMD demonstrates favorable clinical outcomes, with infrequent esophagitis and reintervention for LES dysfunction rarely required.

Treatment of adenoma recurrence after endoscopic mucosal resection.

OBJECTIVE: Residual or recurrent adenoma (RRA) after endoscopic mucosal resection (EMR) of large non-pedunculated colorectal polyps (LNPCPs) of ≥20 mm is a major limitation. Data on outcomes of the endoscopic treatment of recurrence are scarce, and no evidence-based standard exists. We investigated the efficacy of endoscopic retreatment over time in a large prospective cohort. DESIGN: Over 139 months, detailed morphological and histological data on consecutive RRA detected after EMR for single LNPCPs at one tertiary endoscopy centre were prospectively recorded during structured surveillance colonoscopy. Endoscopic retreatment was performed on cases with evidence of RRA and was performed predominantly using hot snare resection, cold avulsion forceps with adjuvant snare tip soft coagulation or a combination of the two. RESULTS: 213 (14.6%) patients had RRA (168 (78.9%) at first surveillance and 45 (21.1%) thereafter). RRA was commonly 2.5-5.0 mm (48.0%) and unifocal (78.7%). Of 202 (94.8%) cases which had macroscopic evidence of RRA, 194 (96.0%) underwent successful endoscopic therapy and 161 (83.4%) had a subsequent follow-up colonoscopy. Of the latter, endoscopic therapy of recurrence was successful in 149 (92.5%) of 161 in the per-protocol analysis, and 149 (73.8%) of 202 in the intention-to-treat analysis, with a mean of 1.15 (SD 0.36) retreatment sessions. No adverse events were directly attributable to endoscopic therapy. Further RRA after endoscopic therapy was endoscopically treatable in most cases. Overall, only 9 (4.2%, 95% CI 2.2% to 7.8%) of 213 patients with RRA required surgery.Thus 159 (98.8%, 95% CI 95.1% to 99.8%) of 161 cases with initially successful endoscopic treatment of RRA and follow-up remained surgery-free for a median of 13 months (IQR 25.0) of follow-up. CONCLUSIONS: RRA after EMR of LNPCPs can be effectively treated using simple endoscopic techniques with long-term adenoma remission of >90%; only 16% required retreatment. Therefore, more technically complex, morbid and resource-intensive endoscopic or surgical techniques are required only in selected cases. TRIAL REGISTRATION NUMBERS: NCT01368289 and NCT02000141.

A Rectum-Specific Selective Resection Algorithm Optimizes Oncologic Outcomes for Large Nonpedunculated Rectal Polyps.

BACKGROUND AND AIMS: Endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) are complementary techniques for large (≥20 mm) nonpedunculated rectal polyps (LNPRPs). A mechanism for appropriate technique selection has not been described. METHODS: We evaluated the performance of a selective resection algorithm (SRA) (August 2017 to April 2021) compared with a universal EMR algorithm (UEA) (July 2008 to July 2017) for LNPRPs within a prospective observational study. In the SRA, LNPRPs with features of superficial submucosal invasive cancer (SMIC) (<1000 µm; Kudo pit pattern Vi), or with an increased risk of SMIC (Paris 0-Is or 0-IIa+Is nongranular, 0-IIa+Is granular with a dominant nodule ≥10 mm) underwent ESD. The remaining LNPRPs underwent EMR. Algorithm performance was evaluated by SMIC identified after EMR, curative oncologic resection (R0 resection, superficial SMIC, absence of negative histologic features), technical success, adverse events, and recurrence at first surveillance colonoscopy. RESULTS: A total of 480 LNPRPs were evaluated (290 UEA, 190 SRA). Median lesion size was 40 (interquartile range, 30-60) mm. SMIC was identified in 56 (11.7%) LNPRPs. Significant differences in SMIC after EMR (SRA 1 [1.0%] vs UEA 35 [12.1%]; P = .001) and curative oncologic resection (SRA n = 7 [33.3%] vs UEA n = 2 [5.7%]; P = .010) were identified. No significant differences in technical success or adverse events were identified (all P > .137). Among LNPRPs with SMIC amenable to curative oncologic resection and which underwent ESD, 100% (n = 7 of 7) were cured. CONCLUSIONS: A rectum-specific SRA optimizes oncologic outcomes for LNPRPs and mitigates the risk of piecemeal resection of cancers.

The Surface Morphology of Large Nonpedunculated Colonic Polyps Predicts Synchronous Large Lesions.

BACKGROUND & AIMS: Large (≥20 mm) nonpedunculated colorectal polyps (LNPCPs) may have synchronous LNPCPs in up to 18% of cases. The nature of this relationship has not been investigated. We aimed to examine the relationship between individual LNPCP characteristics and synchronous colonic LNPCPs. METHODS: Consecutive patients referred for resection of LNPCPs over 130 months until March 2022 were enrolled. Serrated lesions and mixed granularity LNPCPs were excluded from analysis. Patients with multiple LNPCPs resected were identified, and the largest was labelled as dominant. The primary outcome was the identification of individual lesion characteristics associated with the presence of synchronous LNPCPs. RESULTS: There were 3149 of 3381 patients (93.1%) who had a single LNPCP. In 232 (6.9%) a synchronous lesion was detected. Solitary lesions had a median size of 35 mm with a predominant Paris 0-IIa morphology (42.9%) and right colon location (59.5%). In patients with ≥2 LNPCPs, the dominant lesion had a median size of 40 mm, Paris 0-IIa (47.6%) morphology, and right colon location (65.9%). In this group, 35.8% of dominant LNPCPs were non-granular compared with 18.7% in the solitary LNPCP cohort. Non-granular (NG)-LNPCPs were more likely to demonstrate synchronous disease, with left colon NG-LNPCPs demonstrating greater risk (odds ratio, 4.78; 95% confidence interval, 2.95-7.73) than right colon NG-LNPCPs (odds ratio, 1.99; 95% confidence interval, 1.39-2.86). CONCLUSIONS: We found that 6.9% of LNPCPs have synchronous disease, with NG-LNPCPs demonstrating a greater than 4-fold increased risk. With post-colonoscopy interval cancers exceeding 5%, endoscopists must be cognizant of an individual's LNPCP phenotype when examining the colon at both index procedure and surveillance. CLINICALTRIALS: gov, NCT01368289; NCT02000141; NCT02198729.

Cold snare EMR for the removal of large duodenal adenomas.

BACKGROUND AND AIMS: Large (≥15 mm) duodenal adenomas (DAs) are premalignant and require removal. Existing endoscopic resection techniques are compromised by serious adverse events (SAEs), most notably postprocedural bleeding (PPB) and perforation. To ameliorate these problems, we sought to evaluate the novel technique of cold snare EMR (CS-EMR) against the emerging standard of conventional EMR with thermal ablation of the postresection margin (EMR-T) for the safe and effective removal of DAs. METHODS: Consecutive patients were enrolled in a single tertiary center for CS-EMR and prospectively analyzed against a previously reported cohort of EMR-T from the same center. The primary outcome was rate of SAEs. Secondary outcomes were residual or recurrent adenoma at first surveillance endoscopy (SE1) at 6 months and technical success per lesion. RESULTS: Between October 2019 and July 2022, a total of 50 DAs ≥15 mm were removed via CS-EMR (median size, 30 mm [interquartile range (IQR), 19-40 mm]; mean ± standard deviation [SD] patient age, 70 ± 9.2 years) compared with 54 DAs via EMR-T (median size, 30 mm [IQR, 19-40 mm]; mean patient age, 68 ± 12.2 years). CS-EMR had a significantly lower rate of intraprocedural bleeding (2.0% vs 37%, P < .001) and PPB (4.0% vs 16.7%, P = .036). Two cases (4.0%) of immediate perforation occurred in CS-EMR; these were recognized immediately and closed with clips without sequelae. Total SAEs (16.0% vs 16.7%, P = 1) and technical success (100% vs 100%, P = 1) were identical. Recurrence at SE1 was significantly higher with CS-EMR (24.4% vs 2.3%, P = .002). CONCLUSIONS: CS-EMR reduces intraprocedural bleeding and PPB. However, it may increase the risk of immediate perforation and is associated with a significantly higher rate of recurrence at SE1. Further technical refinements are required to optimize endoscopic resection techniques for DAs. (Clinical trial registration number: NCT02306603.).

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.

Intravenous paracetamol for persistent pain after endoscopic mucosal resection discriminates patients at risk of adverse events and those who can be safely discharged.

INTRODUCTION: The frequency and severity of abdominal pain after endoscopic mucosal resection (EMR) of colonic laterally spreading lesions (LSLs) of ≥ 20 mm is unknown, as are the risk factors to predict its occurrence. We aimed to prospectively characterize pain after colonic EMR , determine the rapidity and frequency of its resolution after analgesia, and estimate the frequency of needing further intervention. METHODS: Procedural and lesion data on consecutive patients with LSLs who underwent EMR at a single tertiary referral center were prospectively collected. If pain after colonic EMR, graded using a visual analogue scale (VAS), lasted > 5 minutes, 1 g of paracetamol was administered. Pain lasting > 30 minutes lead to clinical review and upgrade to opiate analgesics. Investigations and interventions for pain were recorded. RESULTS: 67/336 patients (19.9 %, 95 %CI 16.0 %-24.5 %) experienced pain after colonic EMR (median VAS 5, interquartile range 3-7). Multivariable predictors of pain were: lesion size ≥ 40 mm, odds ratio [OR] 2.15 (95 %CI 1.22-3.80); female sex, OR 1.99 (95 %CI 1.14-3.48); and intraprocedural bleeding requiring endoscopic control, OR 1.77 (95 %CI 0.99-3.16). Of 67 patients with pain, 51 (76.1 %, 95 %CI 64.7 %-84.7 %) had resolution of their "mild pain" after paracetamol and were discharged without sequelae. The remaining 16 (23.9 %) required opiate analgesia (fentanyl), after which 11/16 patients (68.8 %; "moderate pain") could be discharged. The 5/67 patients (7.5 %) with "severe pain" had no resolution despite fentanyl; all settled during hospital admission (median duration 2 days), intravenous analgesia, and antibiotics. CONCLUSION: Pain after colonic EMR occurs in approximately 20 % of patients and resolves rapidly and completely in the majority with administration of intravenous paracetamol. Pain despite opiates heralds a more serious scenario and further investigation should be considered.

Endoscopic resection-related colorectal strictures: risk factors, management, and long-term outcomes.

INTRODUCTION: Colorectal strictures related to endoscopic resection (ER) of large nonpedunculated colorectal polyps (LNPCPs) may be problematic. Data on prevalence, risk factors, and management are limited. We report a prospective study of colorectal strictures following ER and describe our approach to management. METHODS: We analyzed prospectively collected data over 150 months, until June 2021, for patients who underwent ER for LNPCPs ≥ 40 mm. The ER defect size was graded as < 60 %, 60 %-89 %, or ≥ 90 % of the luminal circumference. Strictures were considered "severe" if patients experienced obstructive symptoms, "moderate" if an adult colonoscope could not pass the stenosis, or "mild" if there was resistance on successful passage. Primary outcomes included stricture prevalence, risk factors, and management. RESULTS: 916 LNPCPs ≥ 40 mm in 916 patients were included (median age 69 years, interquartile range 61-76 years, male sex 484 [52.8 %]). The primary resection modality was endoscopic mucosal resection in 859 (93.8 %). Risk of stricture formation with an ER defect ≥ 90 %, 60 %-89 %, and < 60 % was 74.2 % (23/31), 25.0 % (22/88), and 0.8 % (6 /797), respectively. Severe strictures only occurred with ER defects ≥ 90 % (22.6 %, 7/31). Defects < 60 % conferred low risk of only mild strictures (0.8 %, 6/797). Severe strictures required earlier (median 0.9 vs. 4.9 months; P = 0.01) and more frequent (median 3 vs. 2; P = 0.02) balloon dilations than moderate strictures. CONCLUSION: Most patients with ER defects ≥ 90 % of luminal circumference developed strictures, many of which were severe and required early balloon dilation. There was minimal risk with ER defects < 60 %.

A novel tool for case selection in endoscopic mucosal resection training.

BACKGROUND: As endoscopic mucosal resection (EMR) of large (≥ 20 mm) adenomatous nonpedunculated colonic polyps (LNPCPs) becomes widely practiced outside expert centers, appropriate training is necessary to avoid failed resection and inappropriate surgical referral. No EMR-specific tool guides case selection for endoscopists learning EMR. This study aimed to develop an EMR case selection score (EMR-CSS) to identify potentially challenging lesions for "EMR-naïve" endoscopists developing competency. METHODS: Consecutive EMRs were recruited from a single center over 130 months. Lesion characteristics, intraprocedural data, and adverse events were recorded. Challenging lesions with intraprocedural bleeding (IPB), intraprocedural perforation (IPP), or unsuccessful resection were identified and predictive variables identified. Significant variables were used to form a numerical score and receiver operating characteristic curves were used to generate cutoff values. RESULTS: Of 1993 LNPCPs, 286 (14.4 %) were in challenging locations (anorectal junction, ileocecal valve, or appendiceal orifice), 368 (18.5 %) procedures were complicated by IPB and 77 (3.9 %) by IPP; 110 (5.5 %) procedures were unsuccessful. The composite end point of IPB, IPP, or unsuccessful EMR was present in 526 cases (26.4 %). Lesion size, challenging location, and sessile morphology were predictive of the composite outcome. A six-point score was generated with a cutoff value of 2 demonstrating 81 % sensitivity across the training and validation cohorts. CONCLUSIONS: The EMR-CSS is a novel case selection tool for conventional EMR training, which identifies a subset of adenomatous LNPCPs that can be successfully and safely attempted in early EMR training.

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

OBJECTIVE: Management 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. We sought to evaluate this in a large tertiary referral cohort. DESIGN: Cases of covert SMIC following pEMR were identified and followed. Oncological outcomes after surgery were divided based on residual intramural cancer, lymph node metastases (LNM) or both. Risk factors for residual intramural cancer and LNM were analysed based on the original pEMR histological variables. Risk parameters were analysed with respect to low and high-risk variables for residual intramural cancer and LNM. RESULTS: Among 3372 cases of large non-pedunculated colorectal polyps, 143 cases of covert SMIC (4.2%) were identified. 109 underwent surgical resection. Histological analysis of pEMR histology was available in 98 of 109 (90%) cases. 62 cases (63%) had no residual malignancy. 36 cases had residual malignancy (residual intramural cancer n=24; LNM n=5; both n=7). All cases of residual intramural cancer could be identified by a R1 histological deep margin. Cases with poor differentiation (PD) and/or lymphovascular invasion (LVI) had a high risk of LNM (12/33), with a very low risk without these criteria (<1%; 0/65). Cases at low risk for LNM with R0 deep margin have a low risk of residual intramural cancer (<1%; 0/35). CONCLUSION: The majority of cases of large non-pedunculated colorectal polyps with covert SMIC following pEMR will have no residual malignancy. The risk of residual malignancy can be ascertained from three key variables: PD, LVI and R1 deep margin.

Outcomes of Thermal Ablation of the Mucosal Defect Margin After Endoscopic Mucosal Resection: A Prospective, International, Multicenter Trial of 1000 Large Nonpedunculated Colorectal Polyps.

BACKGROUND & AIMS: Thermal ablation of the defect margin after endoscopic mucosal resection (EMR-T) for treating large (≥20 mm) nonpedunculated colorectal polyps (LNPCPs) has shown efficacy in a randomized trial, with a 4-fold reduction, in residual or recurrent adenoma (RRA) at first surveillance colonoscopy (SC1). The clinical effectiveness of this treatment, in the real world, remains unknown. METHODS: We sought to evaluate the effectiveness of EMR-T in an international multicenter prospective trial (NCT02957058). The primary endpoint was the frequency of RRA at SC1. Detailed demographic, procedural, and outcome data were recorded. Exclusion criteria were LNPCPs involving the ileo-caecal valve, the appendiceal orifice, and circumferential LNPCPs. RESULTS: During 51 months (May 2016-August 2020) 1049 LNPCPs in 1049 patients (median size, 35 mm; interquartile range, 25-45 mm; right colon location, 53.5%) were enrolled. Uniform completeness of EMR-T was achieved in 989 LNPCPs (95.4%). In this study, 755/803 (94.0%) eligible LNPCPs underwent SC1 (median time to SC1, 6 months; interquartile range, 5-7 months). For LNPCPs that underwent complete EMR-T, the frequency of RRA at SC1 was 1.4% (10/707). CONCLUSIONS: In clinical practice, EMR-T is a simple, inexpensive, and highly effective auxiliary technique that is likely to significantly reduce RRA at first surveillance. It should be universally used for the management of LNPCPs after EMR. https://clinicaltrials.gov; Clinical Trial Number, NCT02957058.

Outcomes of Deep Mural Injury After Endoscopic Resection: An International Cohort of 3717 Large Non-Pedunculated Colorectal Polyps.

BACKGROUND & AIMS: Although perforation is the most feared adverse event associated with endoscopic mucosal resection (EMR), limited data exists concerning its management. Therefore, we sought to evaluate the short- and long-term outcomes of intra-procedural deep mural injury (DMI) in an international multi-center observational cohort of large (≥20 mm) non-pedunculated colorectal polyps (LNPCPs). METHODS: Consecutive patients who underwent EMR for a LNPCP ≥20 mm were evaluated. Significant DMI (S-DMI) was defined as Sydney DMI Classification type III (muscularis propria injury, target sign) or type IV/V (perforation without or with contamination, respectively). The primary outcome was successful S-DMI defect closure. Secondary outcomes included technical success (removal of all visible polypoid tissue during index EMR), surgical referral and recurrence at first surveillance colonscopy (SC1). RESULTS: Between July 2008 to May 2020, 3717 LNPCPs underwent EMR. Median lesion size was 35mm (interquartile range (IQR) 25 to 45mm). Significant DMI was identified in 101 cases (2.7%), with successful defect closure in 98 (97.0%) using a median of 4 through-the-scope clips (TTSCs; IQR 3 to 6 TTSCs). Three (3.0%) patients underwent S-DMI-related urgent surgery. Technical success was achieved in 94 (93.1%) patients, with 46 (45.5%) admitted to hospital (median duration 1 day; IQR 1 to 2 days). Comparing LNPCPs with and without S-DMI, no differences in technical success (94 (93.1%) vs 3316 (91.7%); P = .62) or SC1 recurrence (12 (20.0%) vs 363 (13.6%); P = .15) were identified. CONCLUSIONS: Significant DMI is readily managed endoscopically and does not appear to affect technical success or recurrence.

A Randomized Controlled Trial of Cold Snare Polypectomy Technique: Technique Matters More Than Snare Wire Diameter.

INTRODUCTION: Cold snare polypectomy (CSP) is safe and effective for the removal of small adenomas (≤10 mm); however, reported incomplete resection rates (IRRs) vary. The optimal CSP technique, where a wide margin of normal tissue is resected around the target lesion, and snare design have both been hypothesized to reduce the IRR after CSP. We sought to investigate the efficacy of a thin-wire versus thick-wire diameter snare on IRR, using the standardized CSP technique. METHODS: This was an international multicenter parallel design randomized trial with 17 endoscopists of varying experience (NCT02581254). Patients were randomized in a 1:1 ratio to the use of a thin-wire (0.30 mm) or thick-wire (0.47 mm) snare for CSP of small (≤10 mm) colorectal polyps. The primary end point was the IRR as determined by the histologic assessment of the defect margin after polypectomy. RESULTS: Over 52 months to January 2020, 1,393 patients were eligible. A total of 660 patients with polyps (57.4% male) were randomized to a thin-wire (n = 339) or thick-wire (n = 321) snare. The overall IRR of the cohort was 1.5%. There was no significant difference in the IRR between the thin- and thick-wire arms; relative risk-0.41, 95% CI (0.11-1.56), P = 0.21. No significant differences were observed in the rate of adverse events. DISCUSSION: In this multicenter randomized trial, CSP is safe and effective with very low rates of incomplete resection independent of the diameter of the snare wire used. This suggests that the optimal operator technique is more important than the snare design alone in minimizing residual adenoma after CSP.

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

BACKGROUND AND AIMS: Detailed lesion assessment of large nonpedunculated colorectal polyps (LNPCPs; ≥20 mm) 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. METHODS: 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. RESULTS: Over 39 months to March 2021, 400 consecutive LNPCPs (median lesion size, 35 mm; 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. CONCLUSIONS: 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.).

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

BACKGROUND AND AIMS: The risk of cancer in large nonpedunculated colorectal polyps ≥20 mm (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. METHODS: 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. RESULTS: Patients with LNPCPs referred for endoscopic resection between July 2008 and July 2021 were included. Rectal LNPCPs (n = 618) were larger (median size, 40 mm vs 30 mm; 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). CONCLUSIONS: 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.).

Piecemeal cold snare polypectomy versus conventional endoscopic mucosal resection for large sessile serrated lesions: a retrospective comparison across two successive periods.

OBJECTIVE: Large (≥20 mm) sessile serrated lesions (L-SSL) are premalignant lesions that require endoscopic removal. Endoscopic mucosal resection (EMR) is the existing standard of care but carries some risk of adverse events including clinically significant post-EMR bleeding and deep mural injury (DMI). The respective risk-effectiveness ratio of piecemeal cold snare polypectomy (p-CSP) in L-SSL management is not fully known. DESIGN: Consecutive patients referred for L-SSL management were treated by p-CSP from April 2016 to January 2020 or by conventional EMR in the preceding period between July 2008 and March 2016 at four Australian tertiary centres. Surveillance colonoscopies were conducted at 6 months (SC1) and 18 months (SC2). Outcomes on technical success, adverse events and recurrence were documented prospectively and then compared retrospectively between the subsequent time periods. RESULTS: A total of 562 L-SSL in 474 patients were evaluated of which 156 L-SSL in 121 patients were treated by p-CSP and 406 L-SSL in 353 patients by EMR. Technical success was equal in both periods (100.0% (n=156) vs 99.0% (n=402)). No adverse events occurred in p-CSP, whereas delayed bleeding and DMI were encountered in 5.1% (n=18) and 3.4% (n=12) of L-SSL treated by EMR, respectively. Recurrence rates following p-CSP were similar to EMR at 4.3% (n=4) versus 4.6% (n=14) and 2.0% (n=1) versus 1.2% (n=3) for surveillance colonoscopy (SC)1 and SC2, respectively. CONCLUSIONS: In a historical comparison on the endoscopic management of L-SSL, p-CSP is technically equally efficacious to EMR but virtually eliminates the risk of delayed bleeding and perforation. p-CSP should therefore be considered as the new standard of care for L-SSL treatment.

Optical Evaluation for Predicting Cancer in Large Nonpedunculated Colorectal Polyps Is Accurate for Flat Lesions.

BACKGROUND AND AIMS: The ability of optical evaluation to diagnose submucosal invasive cancer (SMIC) prior to endoscopic resection of large (≥20 mm) nonpedunculated colorectal polyps (LNPCPs) is critical to inform therapeutic decisions. Prior studies suggest that it is insufficiently accurate to detect SMIC. It is unknown whether lesion morphology influences optical evaluation performance. METHODS: LNPCPs ≥20 mm referred for endoscopic resection within a prospective, multicenter, observational cohort were evaluated. Optical evaluation was performed prior to endoscopic resection with the optical prediction of SMIC based on established features (Kudo V pit pattern, depressed morphology, rigidity/fixation, ulceration). Optical evaluation performance outcomes were calculated. Outcomes were reported by dominant morphology: nodular (Paris 0-Is/0-IIa+Is) vs flat (Paris 0-IIa/0-IIb) morphology. RESULTS: From July 2013 to July 2019, 1583 LNPCPs (median size 35 [interquartile range, 25-50] mm; 855 flat, 728 nodular) were assessed. SMIC was identified in 146 (9.2%; 95% confidence interval [CI], 7.9%-10.8%). Overall sensitivity and specificity were 67.1% (95% CI, 59.2%-74.2%) and 95.1% (95% CI, 93.9%-96.1%), respectively. The overall SMIC miss rate was 3.0% (95% CI, 2.3%-4.0%). Significant differences in sensitivity (90.9% vs 52.7%), specificity (96.3% vs 93.7%), and SMIC miss rate (0.6% vs 5.9%) between flat and nodular LNPCPs were identified (all P < .027). Multiple logistic regression identified size ≥40 mm (odds ratio [OR], 2.0; 95% CI, 1.0-3.8), rectosigmoid location (OR, 2.0; 95% CI, 1.1-3.7), and nodular morphology (OR, 7.2; 95% CI, 2.8-18.9) as predictors of missed SMIC (all P < .039). CONCLUSIONS: Optical evaluation performance is dependent on lesion morphology. In the absence of features suggestive of SMIC, flat lesions can be presumed benign and be managed accordingly.

Previously Attempted Large Nonpedunculated Colorectal Polyps Are Effectively Managed by Endoscopic Mucosal Resection.

INTRODUCTION: Endoscopic mucosal resection (EMR) is an effective therapy for naive large nonpedunculated colorectal polyps (N-LNPCPs). The best approach for the treatment of previously attempted LNPCPs (PA-LNPCPs) is undetermined. METHODS: EMR performance for PA-LNPCPs was evaluated in a prospective observational cohort of LNPCPs ≥20 mm. Efficacy was measured by technical success (removal of all visible polypoid tissue during index EMR) and recurrence at first surveillance colonoscopy (SC1). Safety was assessed by clinically significant intraprocedural bleeding, deep mural injury types III-V, clinically significant post-EMR bleeding, and delayed perforation. RESULTS: From January 2012 to October 2019, 158 PA-LNPCPs and 1,134 N-LNPCPs underwent EMR. Median PA-LNPCP size was 30 mm (interquartile range 25-46 mm). Technical success was 93.0% and increased to 95.6% after adjusting for 2-stage EMR. Cold-forceps avulsion with adjuvant snare-tip soft coagulation (CAST) was required for nonlifting polypoid tissue in 73 (46.2%). Median time to SC1 was 6 months (interquartile range 5-7 months). Recurrence occurred in 9 (7.8%). No recurrence was identified among 65 PA-LNPCPs which underwent margin thermal ablation at SC1 vs 9 (18.0%; P < 0.001) which did not. There were significant differences in resection duration (35 vs 25 minutes; P < 0.001), technical success (93.0% vs 96.6%; P = 0.026), and use of CAST (46.2% vs 7.6%; P < 0.001), between PA-LNPCPs and N-LNPCPs. When adjusting for 2-stage EMR, no difference in technical success was identified (95.6% vs 97.8%; P = 0.100). No differences in adverse events or recurrence were identified. DISCUSSION: EMR, using auxillary techniques where necessary, can achieve high technical success and low recurrence frequencies for PA-LNPCPs.