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.

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.

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.

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

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

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.

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.

Impact of en bloc resection on long-term outcomes after endoscopic mucosal resection: a matched cohort study.

BACKGROUND AND AIMS: Residual or recurrent adenoma (RRA) is the major limitation of piecemeal EMR (p-EMR) for large colonic laterally spreading lesions (LSLs) ≥20 mm. En bloc EMR (e-EMR) has been shown to achieve low rates of RRA but specific procedural and long-term outcomes are unknown. Our aim was to compare long-term outcomes of size-matched LSLs stratified by whether they were resected e-EMR or p-EMR. METHODS: Data from a prospective tertiary referral multicenter cohort of large LSLs referred for EMR over a 10-year period were analyzed. Outcomes were compared between sized-matched LSLs (20-25 mm) resected by p-EMR or e-EMR. RESULTS: Five hundred seventy LSLs met the inclusion criteria of which 259 (45.4%) were resected by e-EMR. The risk of major deep mural injury (DMI) was significantly higher in the e-EMR group (3.5% vs 1.0%, P = .05), whereas rates of other intraprocedural adverse events did not differ significantly. Five of 9 (56%) LSLs, with endoscopic features of submucosal invasion (SMI), resected by e-EMR were saved from surgery. RRA at first surveillance was lower in the e-EMR group (2.0% vs 5.7%, P = .04), but this difference was negated at subsequent surveillance. Rates of surgical referral were not significantly different between the groups at either surveillance interval. CONCLUSION: When comparing e-EMR against p-EMR for lesions ≤25 mm in size of similar morphology in a large prospective multicenter cohort, e-EMR offered no additional advantage for predicted-benign LSLs. However, it was associated with an increased risk of major DMI. Thus, en bloc resection techniques should be reserved for lesions suspicious for invasive disease. (Clinical trial registration number: NCT01368289.).

A systematic description of the post-EMR defect to identify risk factors for clinically significant post-EMR bleeding in the colon.

BACKGROUND AND AIMS: Clinically significant post-EMR bleeding (CSPEB) is the most-frequent serious adverse event after EMR of large laterally spreading colonic lesions (LSLs). There is no proven prophylactic therapy, and it remains a significant drawback of EMR. We aimed to systematically describe and evaluate the features of the post-EMR mucosal defect (PED) and their relationship to CSPEB. METHODS: A prospective study of LSLs referred for EMR at a tertiary center was performed. PEDs without visible features were recorded as bland blue. Nonbland blue (NBB) PED features included size, number, and herniation of submucosal vessels and presence of submucosal hemorrhage, fibrosis, fat, and exposed muscle. NBB PEDs were analyzed for association with CSPEB, defined as bleeding occurring after completion of the procedure necessitating readmission or reintervention. RESULTS: From April 2012 to May 2017, 501 lesions in 501 patients were eligible for analysis. The frequency of CSPEB was 30 of 501 (6.0%). More than or equal to 3 visible vessels was a significant predictor of CSPEB (P = .016). None of the following showed a significant correlation with CSPEB: presence of visible vessels, their diameter, herniation, or other nonvascular PED features. Submucosal vessels were more common in the left-sided colon segment (88.6% vs 78.3%, P = .004) and were significantly larger (20.8% vs 12.1% ≥1 mm, P = .037), more numerous (median 4 vessels [interquartile range, 2-7] vs 2 vessels [interquartile range, 1-4], P < .001), and more often herniated (32% vs 22.2%, P = .022). CONCLUSIONS: More than or equal to 3 visible vessels within the PED may be predictive for CSPEB and may define a target group for real-time prophylactic intervention. No other endoscopically visible features of the PEDs were predictive of CSPEB. (Clinical trial registration number: NCT03117400.).

Endoscopic submucosal dissection for suspected early gastric cancer: absolute versus expanded criteria in a large Western cohort (with video).

BACKGROUND AND AIMS: Endoscopic submucosal dissection (ESD) is an effective, minimally invasive, surgery-sparing technique for the treatment of early gastric cancer (EGC). It is not well established whether EGC within the Japanese expanded criteria can be safely and effectively treated using ESD in the West. We describe the outcomes of ESD for endoscopically suspected, biopsy specimen-confirmed EGC and its adenomatous precursor lesions (pEGC) using the Vienna classification of dysplasia in a Western cohort. METHODS: Prospective data were collected on all pEGCs undergoing ESD at a single expert endoscopy center. Outcomes were compared among pEGC, satisfying the Japanese absolute and expanded criteria, those outside criteria, and those specimens that contained low-grade dysplasia (LGD) only. Specialist GI pathologists reviewed and classified all ESD specimens. Patients were followed up at 6 and 12 months. RESULTS: Over 71 months, 135 pEGCs in 121 patients (mean age, 72.0 years; 61.2% men) underwent ESD. Median pEGC size was 20 mm (interquartile range, 15-30), and 62 (45.9%) satisfied the expanded clinical criteria. Perforation occurred in 1.5% and postprocedural bleeding in 5.2%. Forty-two pEGCs (31.1%) contained LGD only. Rates of en bloc and R0 resection were 94.8% and 86.7%, respectively. One hundred seven pEGCs (79.2%) met the absolute or expanded criteria for endoscopic cure. Two pEGCs recurred during follow-up. Ten of 26 patients with pEGC (38.5%) outside criteria for cure underwent surgery after ESD with residual tumor detected in 3 specimens. Fifteen patients with outside criteria for pEGCs did not undergo surgery because of frailty or their expressed wish. Eleven of 15 patients have so far undergone first surveillance with 1 of 11 experiencing endoscopic and histologic recurrence. CONCLUSIONS: ESD is a safe and effective treatment for pEGCs in a Western context. Patients who either decline or are too frail for surgery, with outside criteria resections, may benefit from ESD for local disease control. Large Western studies of ESD for pEGCs are required to define long-term patient outcomes and surveillance guidelines, particularly where pathology shows LGD or high-grade dysplasia only. (Clinical trial registration number: NCT02306707.).

EMR of laterally spreading lesions around or involving the appendiceal orifice: technique, risk factors for failure, and outcomes of a tertiary referral cohort (with video).

BACKGROUND AND AIMS: EMR of sessile periappendiceal laterally spreading lesions (PA-LSLs) is technically demanding because of poor endoscopic access to the appendiceal lumen and the thin colonic wall at the base of the cecum. We aimed to assess the feasibility and safety of EMR for PA-LSLs. METHODS: Consecutive LSLs ≥20 mm and PA-LSLs ≥10 mm detected at 3 academic endoscopy centers from September 2008 until January 2017 were eligible. Prospective patient, procedural, and lesion data were collected. PA-LSLs were compared with LSLs in other colonic locations. RESULTS: Thirty-eight PA-LSLs were compared with 1721 LSLs. Referral for surgery without an attempt at EMR was more likely with PA-LSLs (28.9% vs 5.1%, P < .001), and those that involved a greater percentage of the appendiceal orifice (AO) were less likely to be attempted (P = .038). Most PA-LSLs (10/11) were not attempted because of deep extension into the appendiceal lumen; 2 of 11 of these surgical specimens contained invasive cancer. Once attempted, complete clearance of visible adenoma (92.6% PA-LSLs vs 97.6% LSLs, P = .14), adverse events, and rates of adenoma recurrence did not vary significantly between PA-LSLs and LSLs. All 7 patients with prior appendicectomy achieved complete adenoma clearance. There were no cases of post-EMR appendicitis. Twenty of 22 PA-LSLs (91%) eligible for surveillance avoided surgery to longest follow-up. CONCLUSIONS: EMR is a safe, effective, and durable treatment for PA-LSLs when specific criteria are fulfilled. If the distal margin of the PA-LSL within the AO cannot be visualized or if more than 50% of the circumference of the orifice is involved, surgery should be considered. (Clinical trial registration number: NTC01368289.).

A standardized imaging protocol for the endoscopic prediction of dysplasia within sessile serrated polyps (with video).

BACKGROUND AND AIMS: Dysplasia within sessile serrated polyps (SSPs) is difficult to detect and may be mistaken for an adenoma, risking incomplete resection of the background serrated tissue, and is strongly implicated in interval cancer after colonoscopy. The use of endoscopic imaging to detect dysplasia within SSPs has not been systematically studied. METHODS: Consecutively detected SSPs ≥8 mm in size were evaluated by using a standardized imaging protocol at a tertiary-care endoscopy center over 3 years. Lesions suspected as SSPs were analyzed with high-definition white light then narrow-band imaging. A demarcated area with a neoplastic pit pattern (Kudo type III/IV, NICE type II) was sought among the serrated tissue. If this was detected, the lesion was labeled dysplastic (sessile serrated polyp with dysplasia); if not, it was labeled non-dysplastic (sessile serrated polyp without dysplasia). Histopathology was reviewed by 2 blinded specialist GI pathologists. RESULTS: A total of 141 SSPs were assessed in 83 patients. Median lesion size was 15.0 mm (interquartile range 10-20), and 54.6% were in the right side of the colon. Endoscopic evidence of dysplasia was detected in 36 of 141 (25.5%) SSPs; of these, 5 of 36 (13.9%) lacked dysplasia at histopathology. Two of 105 (1.9%) endoscopically designated non-dysplastic SSPs had dysplasia at histopathology. Endoscopic imaging, therefore, had an accuracy of 95.0% (95% confidence interval [CI], 90.1%-97.6%) and a negative predictive value of 98.1% (95% CI, 92.6%-99.7%) for detection of dysplasia within SSPs. CONCLUSIONS: Dysplasia within SSPs can be detected accurately by using a simple, broadly applicable endoscopic imaging protocol that allows complete resection. Independent validation of this protocol and its dissemination to the wider endoscopic community may have a significant impact on rates of interval cancer. (Clinical trial registration number: NCT03100552.).

Cold-forceps avulsion with adjuvant snare-tip soft coagulation (CAST) is an effective and safe strategy for the management of non-lifting large laterally spreading colonic lesions.

BACKGROUND AND AIMS: Non-lifting large laterally spreading colorectal lesions (LSLs) are challenging to resect endoscopically and often necessitate surgery. A safe, simple technique to treat non-lifting LSLs endoscopically with robust long-term outcomes has not been described. METHODS: In this single-center prospective observational study of consecutive patients referred for endoscopic mucosal resection (EMR) of LSLs ≥ 20 mm, LSLs not completely resectable by snare because of non-lifting underwent standardized completion of resection with cold-forceps avulsion and adjuvant snare-tip soft coagulation (CAST). Scheduled surveillance colonoscopies were performed at 4 - 6 months (SC1) and 18 months (SC2). Primary outcomes were endoscopic evidence of adenoma clearance and avoidance of surgery. The secondary outcome was safety. RESULTS: From January 2012 to October 2016, 540 lifting LSLs (82.2 %) underwent complete snare excision at EMR. CAST was required for complete removal in 101 non-lifting LSLs (17.8 %): 63 naïve non-lifting lesions (NNLs; 62.7 %) and 38 previously attempted non-lifting lesions (PANLs; 37.3 %). PANLs were smaller (P < 0.001) and more likely to be non-granular (P = 0.001) than the lifting LSLs. NNLs were of similar size (P = 0.77) and morphology (P = 0.10) to the lifting LSLs. CAST was successful in all cases and adverse events were comparable to lifting LSLs resected by complete snare excision. Recurrence at SC1 was comparable for PANLs (15.2 %) and lifting LSLs (15.3 %; P = 0.99), whereas NNLs recurred more frequently (27.5 %; P = 0.049); however, surgery was no more common for either type of non-lifting LSL than for lifting LSLs. CONCLUSION: CAST is a safe, effective, and surgery-sparing therapy for the majority of non-lifting LSLs. It is easy to use, inexpensive, and does not require additional equipment.

Wide-field piecemeal cold snare polypectomy of large sessile serrated polyps without a submucosal injection is safe.

BACKGROUND AND STUDY AIMS : Large series suggest endoscopic mucosal resection is safe and effective for the removal of large (≥ 10 mm) sessile serrated polyps (SSPs), but it exposes the patient to the risks of electrocautery, including delayed bleeding. We examined the feasibility and safety of piecemeal cold snare polypectomy (pCSP) for the resection of large SSPs. METHODS: Sequential large SSPs (10 - 35 mm) without endoscopic evidence of dysplasia referred over 12 months to a tertiary endoscopy center were considered for pCSP. A thin-wire snare was used in all cases. Submucosal injection was not performed. High definition imaging of the defect margin was used to ensure the absence of residual serrated tissue. Adverse events were assessed at 2 weeks and surveillance was planned for between 6 and 12 months. RESULTS: 41 SSPs were completely removed by pCSP in 34 patients. The median SSP size was 15 mm (interquartile range [IQR] 14.5 - 20 mm; range 10 - 35 mm). The median procedure duration was 4.5 minutes (IQR 1.4 - 6.3 minutes). There was no evidence of perforation or significant intraprocedural bleeding. At 2-week follow-up, there were no significant adverse events, including delayed bleeding and post polypectomy syndrome. First follow-up has been undertaken for 15 /41 lesions at a median of 6 months with no evidence of recurrence. CONCLUSIONS: There is potential for pCSP to become the standard of care for non-dysplastic large SSPs. This could reduce the burden of removing SSPs on patients and healthcare systems, particularly by avoidance of delayed bleeding.

The clinical significance and synchronous polyp burden of large (≥ 20 mm) sessile serrated polyps in patients without serrated polyposis syndrome.

BACKGROUND: Sessile serrated polyps (SSPs) are important precursors of colorectal carcinoma and interval cancer. Large SSPs (≥ 20 mm) outside the definition of serrated polyposis syndrome (SPS) have not been studied in comparison with SPS. We aimed to describe the characteristics of patients with large SSPs in this context. METHODS: Patients with at least one SSP (≥ 20 mm) were eligible. Data from three consecutive colonoscopies were used to compare clinical and endoscopic characteristics in three patient groups: SPS, a solitary large SSP, and patients with at least two SSPs without fulfilling the criteria for SPS (oligo-SSP). Data on the diagnostic colonoscopy were collected retrospectively, whereas the remaining data was collected prospectively. RESULTS: 67/146 patients (45.9 %) had SPS, 53/146 (36.3 %) had a solitary SSP, and 26/146 (17.8 %) were categorized as oligo-SSP. Personal (16.4 %, 9.4 %, and 11.5 %, respectively) and family (17.9 %, 17.0 %, and 23.1 %, respectively) history of colorectal carcinoma did not differ significantly between groups. Polyp burden was greater in SPS compared with solitary SSP but was not different from oligo-SSP (advanced adenomas: SPS 32.8 % vs. solitary SSP 9.4 % [P = 0.002] vs. oligo-SSP 34.6 % [P = 0.87]; ≥ 10 conventional adenomas: 11.9 % vs. 0 % [P = 0.01] vs. 3.8 % [P = 0.44], respectively). Dysplasia in large SSPs was frequent in all groups (41.1 % overall). SPS was recognized by referring endoscopists in only 9.0 % of cases. CONCLUSION: Patients with oligo-SSPs have similar synchronous polyp burden and clinical characteristics as patients with SPS and may require similar surveillance. Modification of the criteria for the diagnosis of SPS to include this group seems warranted. Patients with a solitary SSP have a lower risk of synchronous polyps, including advanced adenomas. Larger studies are warranted to determine whether these patients may return to standard surveillance following complete examination and clearance of the colon.

The size, morphology, site, and access score predicts critical outcomes of endoscopic mucosal resection in the colon.

BACKGROUND: The SMSA (size, morphology, site, access) polyp scoring system is a method of stratifying the difficulty of polypectomy through assessment of four domains. The aim of this study was to evaluate the ability of SMSA to predict critical outcomes of endoscopic mucosal resection (EMR). METHODS: We retrospectively applied SMSA to a prospectively collected multicenter database of large colonic laterally spreading lesions (LSLs) ≥ 20 mm referred for EMR. Standard inject-and-resect EMR procedures were performed. The primary end points were correlation of SMSA level with technical success, adverse events, and endoscopic recurrence. RESULTS: 2675 lesions in 2675 patients (52.6 % male) underwent EMR. Failed single-session EMR occurred in 124 LSLs (4.6 %) and was predicted by the SMSA score (P < 0.001). Intraprocedural and clinically significant postendoscopic bleeding was significantly less common for SMSA 2 LSLs (odds ratio [OR] 0.36, P < 0.001 and OR 0.23, P < 0.01) and SMSA 3 LSLs (OR 0.41, P  < 0.001 and OR 0.60, P = 0.05) compared with SMSA 4 lesions. Similarly, endoscopic recurrence at first surveillance was less likely among SMSA 2 (OR 0.19, P < 0.001) and SMSA 3 (OR 0.33, P < 0.001) lesions compared with SMSA 4 lesions. This also extended to second surveillance among SMSA 4 LSLs. CONCLUSION: SMSA is a simple, readily applicable, clinical score that identifies a subgroup of patients who are at increased risk of failed EMR, adverse events, and adenoma recurrence at surveillance colonoscopy. This information may be useful for improving informed consent, planning endoscopy lists, and developing quality control measures for practitioners of EMR, with potential implications for EMR benchmarking and training.

A standardized imaging protocol is accurate in detecting recurrence after EMR.

BACKGROUND AND AIMS: EMR of large laterally spreading lesions (LSL) in the colon is a safe and effective alternative to surgery. Post-EMR scar assessment currently involves taking biopsy specimens of the scar to detect residual or recurrent adenoma (RRA). The accuracy of endoscopic imaging of the post-EMR scar is unknown. We aimed to determine the accuracy of a standardized imaging protocol in post-EMR scar assessment. METHODS: Prospective, single-center data from the Australian Colonic EMR study were analyzed. Consecutive patients undergoing first surveillance colonoscopy (SC1) after EMR of a large LSL were eligible. All scars were sequentially examined with high-definition white light (HD-WL) and narrow-band imaging (NBI) in a standardized fashion and then biopsies were performed. Endoscopic recurrence (recurrence at the post-EMR scar detected by systematic endoscopic assessment) was compared with the histologic findings. RESULTS: One hundred eighty-three post-EMR scars were included. Thirty of 183 (16.4%) were confirmed to have RRA histologically at SC1. Thirty-seven of 183 (20.2%) post-EMR scars demonstrated RRA endoscopically. The sensitivity and specificity of endoscopic RRA detection were 93.3% (95% confidence interval [CI], 77.9%-99.2%) and 94.1% (95% CI, 89.1%-97.3%), respectively. The positive predictive value was 75.7% (95% CI, 58.8%-88.2%) and the negative predictive value was 98.6% (95% CI, 95.1%-99.8%). The diagnostic accuracy was 94.0%. Sensitivity was higher for the combination of HD-WL and NBI as opposed to HD-WL alone (93.3% vs 66.7%). The specificity was high for both HD-WL and HD-WL + NBI (96.1% and 94.1%, respectively). Flat morphology of RRA was better seen with NBI (P = .002). CONCLUSIONS: Endoscopic detection of RRA in the post-EMR scar is highly accurate using a standardized imaging protocol with HD-WL and NBI. This allows real-time, accurate detection of recurrence and its concurrent treatment, and raises the possibility that routine biopsy of the post-EMR scar may not be necessary.

Adenoma recurrence after piecemeal colonic EMR is predictable: the Sydney EMR recurrence tool.

BACKGROUND AND AIMS: EMR is the primary treatment of large laterally spreading lesions (LSLs) in the colon. Residual or recurrent adenoma (RRA) is a major limitation. We aimed to identify a robust method to stratify the risk of RRA. METHODS: Prospective multicenter data on consecutive LSLs ≥20 mm removed by piecemeal EMR from 8 Australian tertiary-care centers were included (September 2008 until May 2016). A logistic regression model for endoscopically determined recurrence (EDR) was created on a randomly selected half of the cohort to yield the Sydney EMR recurrence tool (SERT), a 4-point score to stratify the incidence of RRA based on characteristics of the index EMR. SERT was validated on the remainder of the cohort. RESULTS: Analysis was performed on 1178 lesions that underwent first surveillance colonoscopy (SC1) (median 4.9 months, interquartile range [IQR] 4.9-6.2). EDR was detected in 228 of 1178 (19.4%) patients. LSL size ≥40 mm (odds ratio [OR] 2.47; P < .001), bleeding during the procedure (OR 1.78; P = .024), and high-grade dysplasia (OR 1.72; P = .029) were identified as independent predictors of EDR and allocated scores of 2, 1, and 1, respectively to create SERT. Lesions with SERT scores of 0 (SERT = 0) had a negative predictive value of 91.3% for RRA at SC1, and SERT was shown to stratify RRA to specific follow-up intervals by using Kaplan Meier curves (log-rank P < .001). CONCLUSIONS: Guidelines recommend SC1 within 6 months of EMR. SERT accurately stratifies the incidence of RRA after EMR. SERT = 0 lesions could safely undergo first surveillance at 18 months, whereas lesions with SERT scores between 1 and 4 (SERT 1-4) require surveillance at 6 and 18 months. (Clinical trial registration number: NCT01368289.).

Two-stage endoscopic mucosal resection is a safe and effective salvage therapy after a failed single-session approach.

Background and study aims Endoscopic mucosal resection (EMR) of laterally spreading colonic lesions ≥ 20 mm (LSLs) is ideally performed in a single session (ssEMR) and avoids surgery in > 90 % of patients. We investigated whether a second attempt is safe or useful when ssEMR fails at a tertiary center. Patients and methods In a multicenter prospective observational study of patients with LSL treated by EMR at four tertiary centers over 8 years, incompletely resected LSLs were referred for surgery or underwent two-stage EMR (tsEMR). At tsEMR, the scar was located and all visible residual tissue removed by snare, with thermal treatment permitted thereafter. Scheduled surveillance was performed at 5 months (SC1) and 18 months (SC2). The primary outcome was avoidance of surgery. Results A total of 1944 LSLs (median size 35 mm) underwent EMR. ssEMR was unsuccessful in 127 lesions, 43 of which underwent tsEMR, with success in 36 (83.7 %). Compared with ssEMR, tsEMR lesions were larger (median size 50 mm vs. 30 mm; P < 0.001), exhibited more submucosal fibrosis (P < 0.001), and histology was more often tubular adenoma and less often serrated (P = 0.005). Lesions mainly required tsEMR for nonlifting (41.9 %) or poor endoscopic access (37.2 %). Failure of tsEMR was predicted by larger LSL (P = 0.03). Safety was comparable to ssEMR. Of the 33 LSLs that underwent tsEMR for benign disease and completed first surveillance, 27 (81.8 %) avoided surgery to long term follow-up. Conclusions tsEMR shows promise as a salvage therapy for LSLs that cannot be resected in a single session for patients in whom other options such as surgery are not preferred or not possible.Trial registered at ClinicalTrials.gov (NCT01368289).

The influence of clips on scars after EMR: clip artifact.

BACKGROUND AND AIMS: Laterally spreading lesions ≥20 mm are conventionally removed by EMR. Endoscopic clips are increasingly used to mitigate the risk of delayed bleeding. Clips may alter the endoscopic appearance of the scar after EMR, interfering with the assessment of adenoma recurrence. We aimed to evaluate this. METHODS: Prospective, single-center data from the Australian Colonic Endoscopic resection study (January 2011-May 2015) were analyzed. Patients undergoing EMR of laterally spreading lesions with endoscopic clips used at the EMR defect were eligible. Data included patient and lesion characteristics and procedural, clinical, and histologic outcomes. RESULTS: Clips were used in 111 of 885 lesions (12.5%). A total of 62 of 111 clipped lesions had standardized, high-definition, white light, and narrow-band images of the scars after EMR at first surveillance colonoscopy, and the patients were enrolled. Analysis of the images showed 4 situations: a bland scar (N = 27), residual adenoma (N = 6), mucosal elevation with normal pit pattern (N = 14), or granulation tissue related to the presence of residual clips (N = 15). The latter 2 entities were termed post-EMR scar clip artifact (ESCA). Overall, 29 of 62 previously clipped EMR sites (46.8%) had ESCA at a median follow-up of 5.2 months. Twenty scars had residual clips, and 15 of 20 (75.0%) showed ESCA (P = .002). Lesions clipped for prophylaxis of bleeding were more likely to show ESCA than those clipped for deep mural injury or intraprocedural bleeding (65.5% vs 41.7%; P = .006). ESCA was associated with female sex (P = .010) and greater age (P = .011). CONCLUSIONS: ESCA is characterized by a nodular elevation of the mucosa with a normal pit pattern and can occur with or without residual clips. Prophylactic clip closure and the presence of residual clips are associated with ESCA. ( CLINICAL TRIAL REGISTRATION NUMBER: NCT01368289.).