Use Of Endoscopic Mucosal Resection Research Articles

A158 FINDINGS FROM A MULTIDISCIPLINARY DATABASE FOR PATIENTS WITH BARRETT'S ESOPHAGUS AND EARLY ESOPHAGEAL ADENOCARCINOMA

Abstract Background Previously, Barrett’s esophagus (BE) with high grade dysplasia (HGD) or neoplasia was treated with esophagectomy; however, recent guidelines support the use of endoscopic mucosal resection (EMR) for T1a esophageal adenocarcinoma (EAC) and potentially T1b EAC. Long term data for outcomes from EMR are lacking and these treatments are often provided with minimal collaboration between gastroenterologists and thoracic surgeons. Purpose Our primary aim was to describe the findings from our multidisciplinary database of patients with Barrett’s esophagus and EAC undergoing endoscopic treatment. Secondary aims were to compare the overall survival and recurrence-free survival of patients undergoing endoscopic resection to those undergoing esophagectomy. Method For the endoscopic resection cohort, a combined retrospective and prospective database was created containing demographic, clinical, and oncologic variables for patients undergoing endoscopic resection for early stage EAC from 2009 to 2021. For the esophagectomy cohort, a pre-existing retrospective database including patients undergoing esophagectomy for esophageal cancer from 2012 to 2018 at a single institution was used. A multivariate cox proportional hazards model was developed for recurrence-free survival and overall survival using a hypothesis driven approach. A kaplan-meier (KM) curve with associated log-rank test was created to evaluate recurrence-free survival and overall survival stratified by treatment modality. Result(s) A total of 108 patients were included in the analysis (73 EMR, 35 esophagectomy). Baseline characteristics including age, sex, and co-morbidities were similar among the two groups. KM curves stratified by treatment modality are provided in Figure 1. Esophagectomy was associated with greater DFS on univariate log-rank test (p = 0.0127), but no difference in OS (p = 0.9306). There was no significant difference between esophagectomy and endoscopic resection in the cox-model for OS (HR 1.03, 95% CI 0.45-2.32, p = 0.914). Endoscopic resection was associated with increased hazards of disease recurrence in the cox model for DFS (HR 2.56, 95% CI 1.1-6.0, p = 0.032). In the logistic regression model, high grade disease (OR 5.43, 95% CI 1.1 – 26.1, p = 0.035) and submucosal involvement (OR 7.8, 1.9-31.4, p = 0.004) were identified as significant predictors of positive margin necessitating esophagectomy after initial endoscopic resection. All patients who experienced a positive margin after endoscopic therapy were evaluated by a thoracic surgeon and proceeded to esophagectomy. Conclusion(s) In this largely retrospective analysis, our multidisciplinary approach was shown to be highly efficacious in the treatment of BE with EAC. Through optimizing collaboration between thoracic surgeons and gastroenterologists, patients receive the best therapeutic approach for their unique condition, taking into account oncologic factors and clinical comorbidities. Please acknowledge all funding agencies by checking the applicable boxes below None Disclosure of Interest None Declared

214: THE ADDITION OF ENDOSCOPIC ULTRASOUND AND PET IMAGING HAVE MINIMAL IMPACT ON DECISION-MAKING IN EARLY OESOPHAGEAL CANCER

Abstract Background and aim With the increasing use of endoscopic mucosal resection (EMR) for the staging and management of early oesophageal cancer (EOC), the value of multiple staging investigations remains clear. Methods A single centre, ethically approved, prospective database of patients treated for EOC between 2000 and 2018 was analysed. This incorporated a transition period from oesophagectomy to endoscopic therapy as the treatment of choice for early cancers. Patients were staged with endoscopic ultrasound (EUS), Positron Emission Tomography (PET) and Computed Tomography (CT) with the accuracy and decision-making utility of these investigations assessed. Results In total 306 patients with glandular dysplasia or early adenocarcinoma were included (EMR n = 184; Surgery n = 113; EMR and Surgery n = 23). In patients treated by EMR staging patterns were similar for all modalities with low overall accuracy (Correct staging CT 40.1%, EUS 29.6%, PET 11%; Understaging CT 54.2%, EUS 51.9%, PET 82.9%; Overstaging CT 5.6%, EUS 18.5%, PET 6.1%). Incorrect overstaging that might have changed management occurred in 10 patients (3.6%) for T staging (T2) and 14 patients (5%) for N+. Similar staging inaccuracies persisted in both the surgery alone group and in those patients treated by oesophagectomy following EMR. Lymph node disease identified following surgery was rare (n = 8) and staging accuracy for these patients was low (CT 12.5%, EUS 12.5%, PET 0%). Conclusion In EOC, staging accuracy is low and the addition of EUS and PET change decision making in very few patients over and above standard CT. Factors predicting the need for surgery are predominantly obtained from the EMR histology rather than staging investigations. EUS and PET should only be used selectively in patients being assessed for EOC.

EMR and ESD: Indications, techniques and results

Endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) are two well-known endoscopic resection procedures used for advance gastrointestinal lesions. As compared to standard polypectomy techniques, EMR and ESD provide wider and deeper resection margins and allow en bloc removal of lesions for more detailed pathology with curative intent for early neoplastic gastrointestinal lesions. Both procedures have their advantages and disadvantages which will be discussed in detail in this review article. Recently there have been advancements in the techniques of EMR and ESD with addition in new equipment. We will also discuss current guidelines recommending use of EMR and/or ESD in various clinical scenarios.

A127 ENDOSCOPIC MUCOSAL RESECTION FOR DYSPLASTIC AND NEOPLASTIC BARRETT’S ESOPHAGUS: FINDINGS FROM A FOREGUT NEOPLASIA MULTIDISCIPLINARY DATABASE

Abstract Background Previously, Barrett’s esophagus with high grade dysplasia (HGD) or neoplasia was treated with esophagectomy, which is associated with a high postoperative morbidity and mortality rate. Recent guidelines support the use of endoscopic mucosal resection (EMR) for T1a esophageal adenocarcinoma (EAC) and potentially T1b EAC; however, data on long term outcomes of endoscopic treatment is lacking. We created a combined prospective and retrospective multidisciplinary database to monitor outcomes of patients with Barrett’s esophagus undergoing endoscopic treatment. Aims Our primary aim was to compare outcomes of EMR and esophagectomy in patients presenting with BE and HGD, and/or early EAC. Methods A collaboration of gastroenterologists, general surgeons and thoracic surgeons from the University of Alberta, Edmonton, Alberta, provided input on the development of the database. All patients referred to the Northern Alberta Endoscopic Ablation Program from 2009–2021 who received at least one endoscopic treatment were included. A sub-analysis of all patients with pathologic confirmation of HGD, and/or early EAC was conducted to compare outcomes of EMR and esophagectomy. Results A total of 212 patients have been entered into the database. The most common findings were HGD, low grade dysplasia (LGD), and adenocarcinoma, respectively. All patients (n=48) who had at least LGD reached complete eradication of dysplasia (CE-D) and 95.8% reached complete eradication of intestinal metaplasia (CE-IM). Of those patients that reached CE-D, 8.3% developed recurrence of dysplasia (n=4). In the sub-analysis, 74 patients (76.3%) received endoscopic therapy while 23 patients (23.7%) received endoscopic therapy then ultimately an esophagectomy. There were significantly more T1b lesions in the esophagectomy group compared to the EMR group ( p<0.0001). Of all the patients in the EMR group, only 5.4% (n=4) had treatment related complications. Of patients receiving an esophagectomy, 60.9% (n=14) experienced treatment related complications. The mean length of stay for patients in the EMR group was 1.03 +/- 0.2 days, compared to 16.5 +/- 11.8 days for esophagectomy ( p<0.0001). Conclusions EMR provides definitive and durable treatment for BE lesions classified as T1b or less severe, with fewer complications and a shorter length of hospital stay than esophagectomy. Funding Agencies Alberta Innovates Health Solutions

Variation in Diagnosis, Treatment, and Outcome of Esophageal Cancer in a Regionalized Care System in Ontario, Canada

Esophageal cancer remains one of the most deadly cancers, ranking sixth highest among cancers leading to the greatest years of life lost. To determine how patients with esophageal cancer are diagnosed and treated in Ontario's regionalized thoracic surgery centers. This cohort study included patients diagnosed with esophageal cancer between January 1, 2010, and December 31, 2018, identified from the Ontario Cancer Registry, in a single-payer health care system with regionalization of thoracic surgery in the province of Ontario, Canada. Exposures included incidence of esophageal cancer and stage at diagnosis; time from the first health care visit until treatment; and the use of specialist consultations, endoscopic ultrasonography, positron emission tomography and computed tomography, endomucosal resection, esophagectomy, neoadjuvant therapy, adjuvant therapy, radiation alone, and chemotherapy alone or in combination with other treatment. Outcome measures included wait times, health care use, treatment, and overall survival. Data were analyzed from March 2020 to February 2021. There were 10 364 patients (mean [SD] age, 68.3 [11.9] years; 7876 men [76%]) identified during the study period. The incidence of esophageal cancer increased over the study period from 1041 in 2010 to 1309 in 2018, which was driven by a 30% increase in the number of adenocarcinomas. The time from first health care encounter to start of treatment was a median 93 days (interquartile range, 56-159 days). Endoscopic ultrasonography was observed for 12% of patients, and positron emission tomography and computed tomography (CT) in 45%. Use of endoscopic mucosal resection was observed for 8% of patients with stage 0 to I disease. A total of 114 of 547 patients (21%) receiving endoscopic resection had a subsequent esophagectomy. Only 2778 patients (27%) had consultations with a thoracic surgeon, a medical oncologist, and a radiation oncologist, whereas 1514 patients (15%) did not see any of these specialists. Of 3047 patients who had an esophagectomy, those receiving neoadjuvant therapy had better overall survival (median survival, 36 months; 95% CI, 32-39 months) than patients who received esophagectomy alone (median survival, 27 months; 95% CI, 24-30 months) or those who received esophagectomy with adjuvant therapy (median survival, 36 months; 95% CI, 32-44 months) despite significant early mortality (log-rank P < .001). There was significant variation in treatment modality across hospitals: esophagectomy ranged from 5% to 39%; esophagectomy after neoadjuvant therapy ranged from 33% to 93%; and esophagectomy followed by adjuvant therapy ranged from 0 to 34% (P < .001). Perioperative mortality was higher at 30 days for patients receiving esophagectomy at low-volume centers (odds ratio [OR], 3.66; 95% CI, 2.01-6.66) and medium-volume centers (OR, 2.07; 95% CI, 1.33-3.23) compared with high-volume centers (P < .001). A longer wait time until treatment was associated with better overall survival (median overall survival was 15 to 17 days vs 5 to 8 days for patients who received treatment earlier than 30 days vs 30 days or longer after diagnosis; P < .001). The results of this cohort study suggest that despite regionalization, there was significant regional variability in volumes at designated centers and in the evaluation and treatment course for patients with esophageal cancer across Ontario.

S1849 Intraluminal Duodenal Diverticulum: Double Barrel Lumen Treated With Water Immersion Septotomy and Endoscopic Mucosal Resection

INTRODUCTION: Intraluminal duodenal diverticulum (IDD) is a rare congenital condition caused by incomplete recanalization of the foregut. Surgical diverticulotomy was historically used to treat patients with symptomatic IDD. Underwater septotomy and endoscopic mucosal resection (EMR) present a minimally invasive approach to relieve an obstructing IDD lesion. Our case report demonstrates effective management of IDD with underwater septotomy and EMR. CASE DESCRIPTION/METHODS: A 78-year-old male presented with progressive chronic post-prandial nausea and bloating associated with early satiety and substernal heartburn that was only moderately relieved with proton pump inhibitor therapy. Initial esophagogastroduodenoscopy (EGD) revealed post-bulbar duodenal stricture and symptoms persisted following balloon dilation. Repeat EGD showed IDD with double barrel lumen of the duodenal mucosa. Due to persistent symptoms, the decision was made to intervene on the obstructive IDD. The IDD was visualized in the second part of the duodenum. The obstructing lesion was tented back to visualize the septum, which was injected with saline-methylene blue lifting agent. Initial limited EMR was performed via snare excision to debulk diverticular tissue. Next, underwater septotomy was performed with a 20-mm snare tip. EMR of the lesion was then completed and the lesion was removed by snare. The mucosal defect closed with six endoscopic clips to achieve hemostasis. The next day, the patient developed gastrointestinal bleeding due to a visible vessel and hemostasis was again achieved with 7 French gold probe cautery and one additional endoscopic clip. DISCUSSION: Underwater septotomy and EMR successfully relieved obstruction due to IDD. Snare tip for septotomy was an effective alternative to needle knife and preserved resources by employing tools already being used for EMR. Underwater approach allowed for clear visualization due to minimal electrosurgical smoke production and potentially reduced risk of perforation compared to insufflation. This case highlights the use of underwater septotomy and EMR as minimally invasive management for obstructing IDD lesions.

Su1305 A SAFE AND COST EFFECTIVE STRATEGY FOR THE MANAGEMENT OF SMALL ASYMPTOMATIC GASTRIC SUBEPITHELIAL TUMORS: A CASE SERIES

Gastric subepithelial tumors (SETs) are relatively common incidental findings encountered on endoscopy. Current ASGE guidelines for small SETs (<2cm) arising from the second and third echolayers recommend tissue acquisition for diagnosis or endoscopic mucosal resection (EMR) for lesions that are symptomatic or increase in size over time. If tissue acquisition is non-diagnostic, it is recommended that these patients have endoscopic ultrasound (EUS) surveillance at poorly defined intervals. In addition to the cumulative risk of anesthesia and significant cost of repeated endoscopy, diagnosis may be challenging because of the low diagnostic yield of tissue acquisition methods currently available for these SETs and the limited accuracy of EUS with endosonographic imaging alone. We propose that routine EMR of asymptomatic gastric SETs <2cm arising from the second and third echolayers is a safe and more cost effective strategy for management than current surveillance recommendations. Provation was queried to identify patients undergoing EUS with a coded diagnosis of “gastric nodule” or “intramural lesion” from September 2017 through September 2019 at our institution. Inclusion criteria for analysis were gastric SETs <2cm arising from the second and third echolayers and removed with EMR. These cases were reviewed for EMR-related complications and pathology of removed specimens. Of the 96 cases identified, 13 patients with 14 distinct lesions met inclusion criteria. All lesions were removed via endoscopic cap band mucosectomy. The mean age of patients was 58.6 years with a female predominance (69.2%). The mean size of these gastric SETs was 7.4 mm. Lesions were most commonly located in the gastric antrum (64%). Pancreatic heterotopia (29%), gastric mucosa (29%), and inflammatory fibroid polyps (23%) were most the most commonly reported pathologic findings. Notably, no carcinoid or other neoplastic lesions were identified. Hemostatic clips were used in 50% of removed lesions. No procedural complications such as perforation were identified. Currently available tissue acquisition methods for small gastric SETs are not always diagnostic, obligating many patients to the EUS surveillance pathway. This results in repeated procedures with a cumulative risk of adverse events. Our results are consistent with published literature showing that asymptomatic SETs <2 cm originating from the second and third echolayers are often benign and can be safely removed by EMR. The more universal use of EMR in this context would increase diagnostic yield, reduce procedural risks, and provide substantial cost savings by eliminating the need for surveillance. As evidence mounts for the safe and efficacious use of EMR in this context, updated guidelines to include this as a viable option need to be considered.

Endoscopic Mucosal Resection

Endoscopic mucosal resection (EMR) is an effective diagnostic and potentially therapeutic treatment of dysplastic Barrett's esophagus and early intramucosal esophageal carcinoma. Appropriate patient selection for therapeutic resection can follow a diagnostic endoscopic resection, and liberal use of EMR is encouraged to gain insight into the metastatic potential of any early esophageal tumor that appears amenable to EMR. EMR is a low-risk procedure; multidisciplinary groups should consider it a vital component of the staging algorithm for esophageal cancer.

225 Barriers to Endoscopic Mucosal Resection of Large Colorectal Lesions: Results of a Nationwide Survey

INTRODUCTION: Over 90% of complex colon polyps that lack overt features of cancer can be removed using endoscopic mucosal resection (EMR) techniques. EMR is more cost-effective and is associated with less morbidity and mortality than surgery. However, rates of surgical resection have been rising even though extensive evidence suggests endoscopic resection should be first line for the management of complex colon polyps. We aimed to assess perceived barriers towards the utilization of EMR for &gt;2 cm polyps among American endoscopists. METHODS: We administered a 21 question web-based survey with Qualtrics software (Provo, UT, USA). The American College of Gastroenterology distributed the survey to their mailing list on January 24, 2019 and closed it on February 21, 2019. We assessed endoscopist and practice characteristics as well as perceived barriers and facilitators of EMR, and compared responses between providers who performed 0–1 EMR per month with 2 or more EMR per month to determine which barriers and facilitators influence the utilization of EMR. RESULTS: A total of 8,797 practitioners received the survey, with 415 replies (4.7%). Provider demographics are summarized in Table 1. 275 providers (66.7%) reported performing 2 or more EMRs per month. 146 providers (35.1%) felt their fellowship prepared them poorly for large polyp resection. 237 providers (57.1%) felt that the incorporation of EMR training into fellowship would be very beneficial, followed by higher reimbursement (N = 176, 42.4%) and training on EMR technique (N = 154, 37.1%). Providers who performed 1 or fewer EMR per month were significantly more likely to report that lack of structured training, fear of complications, and uncertainty regarding which lesions were amenable to endoscopic management were barriers to routine use of EMR than providers who performed 2 or more EMR per month (Figure 1). They were also more likely to report improved training to be a facilitator for EMR utilization whereas providers who performed 2 or more EMR per month were more likely to report increased reimbursement as a facilitator for EMR utilization (Figure 2). CONCLUSION: We found that endoscopists identified lack of training to be a major barrier to performing EMR, especially for low-volume providers. Increasing reimbursement and training were important potential facilitators identified in our study. Future quality improvement efforts should target these key practice aspects to optimize the endoscopic management of complex colon lesions.

2163 Successful Endoscopic Mucosal Resection for Duodenal Neuroendocrine Tumor: To Net a NET

INTRODUCTION: Neuroendocrine tumors (NET) are rare (0.49 % of all malignancies) and slow-growing that can arise anywhere in the body from neuroendocrine cells. They are most commonly seen in the gastrointestinal tract, but compromise &lt;2% of all gastrointestinal malignancies. NETs in the duodenum are even less common as they make up 2.6 % of all NETs. This case illustrates the appropriate diagnosis and management of a rare gastrointestinal malignancy – duodenal NET. Endoscopic mucosal resection (EMR) has become more common for the management of duodenal NETs, but guidelines are still evolving. CASE DESCRIPTION/METHODS: A 79-year-old male with a medical history of prostate cancer, stage 3 chronic kidney disease, gastroesophageal reflux disease with occasional dysphagia underwent an upper endoscopy which revealed a benign Schatzki ring that was dilated. A single 7 mm shiny nodule in the duodenal bulb was biopsied revealing a grade 1 NET. Endoscopic ultrasound (EUS) to assess showed the lesion measured 4.4 mm in thickness and 6 mm in diameter, originate within the submucosa and there was no surrounding lymphadenopathy. The lesion was raised by injecting it with a solution of epinephrine and methylene blue. A ligation-assisted endoscopic mucosal resection was completed. Pathology noted a well-differentiated grade 1 NET measuring 6 mm involving the submucosa and mucosa with no malignant cells noted in the margins. He returned home without any complications. DISCUSSION: The diagnosis of neuroendocrine tumors is difficult given their rarity, size, and potential asymptomatic presentation. For small, non-functional, localized duodenal NETs, resection is the goal and endoscopic therapy is becoming the preferred method of resection. Numerous surgical and endoscopic techniques have been explored; however, the optimal method has yet to be determined. This case shows the successful use of EMR after EUS evaluation in treating a duodenal NET with evidence of clean margins on pathology. We were able to describe a rarely encountered tumor and highlight the evolving use of advanced endoscopy in its management. Clinicians should be suspicious for NETs when encountering a shiny-appearing nodule in the gastrointestinal tract.

Treatment of high-grade dysplasia and intramucosal carcinoma using radiofrequency ablation or endoscopic mucosal resection + radiofrequency ablation: Meta-analysis and systematic review.

BACKGROUNDThe progression of Barrett’s esophagus (BE) to early esophageal carcinoma occurs sequentially; the metaplastic epithelium develops from a low-grade dysplasia to a high-grade dysplasia (HGD), resulting in early esophageal carcinoma and, eventually, invasive carcinoma. Endoscopic approaches including resection and ablation can be used in the treatment of this condition.AIMTo compare the effectiveness of radiofrequency ablation (RFA) vs endoscopic mucosal resection (EMR) + RFA in the endoscopic treatment of HGD and intramucosal carcinoma.METHODSIn accordance with PRISMA guidelines, this systematic review included studies comparing the two endoscopic techniques (EMR + RFA and RFA alone) in the treatment of HGD and intramucosal carcinoma in patients with BE. Our analysis included studies involving adult patients of any age with BE with HGD or intramucosal carcinoma. The studies compared RFA and EMR + RFA methods were included regardless of randomization status.RESULTSThe seven studies included in this review represent a total of 1950 patients, with 742 in the EMR + RFA group and 1208 in the RFA alone group. The use of EMR + RFA was significantly more effective in the treatment of HGD [RD 0.35 (0.15, 0.56)] than was the use of RFA alone. The evaluated complications (stenosis, bleeding, and thoracic pain) were not significantly different between the two groups.CONCLUSIONEndoscopic resection in combination with RFA is a safe and effective method in the treatment of HGD and intramucosal carcinoma, with higher rates of remission and no significant differences in complication rates when compared to the use of RFA alone.

PS02.093: LYMPH NODE METASTASES IN T1 OESOPHAGEAL ADENOCARCINOMA: WHAT IS THE REAL RISK IN EARLY OESOPHAGEAL CANCER?

Abstract Background Lymph node status is regarded as the most important factor for prognosis for oesophageal cancer. T1 oesophageal adenocarcinoma management has shifted from oesophagectomy only to include endoscopic management as part of the algorithm, with some bodies (National Comprehensive Cancer Network (NCCN) 2016) recommending it for management of T1a disease and selected T1b disease. We reviewed the literature to assess the true risk of lymph node metastasis in patients with T1 oesophageal adenocarcinoma. Methods Medline, Embase, Pubmed and Cochrane where searched for manuscripts in english reviewing the lymph node metastasis in superficial (T1) oesophageal adenocarcinoma. The main outcome was reviewing the risk of lymph node metastasis in T1a and T1b oesophageal adenocarcinoma. Secondary outcomes looked at the rate of lymph node metastasis for T1b cancers based on degree of submucosal involvement (SM1, SM2 and SM3). Studies were excluded if neo-adjuvant chemotherapy or radiotherapy were received and if the surgical lymph node yield was &lt; 15 lymph nodes. Results 38 Studies were identified. 22 studies were excluded due to low lymph node yield (&lt; 15) or insufficient statistical analysis. For the 16 studies, a total of 1422 cases were included. 533 patients had T1a adenocarcinoma with 11 patients demonstrating positive lymph nodes (2%). 849 had T1b adenocarcinoma with 189 patients demonstrating positive lymph nodes (22%). Eight Studies did subgroup analysis of T1b lesions with a total of 365 patients identified. The rate of lymph node positivity for SM1, SM2 and SM3 was 17.9%, 16.6% and 29.6% respectively. Conclusion Early oesophageal adenocarcinoma (T1) is increasing in prevalence due to surveillance of pre-malignant conditions (Barrett's Oesophagus). Recently some bodies recommend the use of endoscopic mucosal resection as first line therapy for T1a disease. It is important to inform our patients the risk of lymph node metastasis is low but significant (2%). Given in specialised units, oesophagectomy can be performed with low mortality (&lt; 1%) and morbidity with good quality of life it is justifiable to recommend oesophagectomy or endoscopic management in patients who are fit enough for surgery. For T1b disease an oesophagectomy is the gold standard of treatment given the significant risk of lymph node positivity (22%). Disclosure All authors have declared no conflicts of interest.

Closing the Gap: Deployment of an Over-the-Scope Clip After Colonic Endoscopic Mucosal Resection

Background: Endoscopic mucosal resection (EMR) is an increasingly common intervention for removal of mucosal neoplasms and a popular alternative to surgical resection; especially in the setting of larger sessile polyps or laterally spreading tumors. There is a risk of post-procedure bleeding and perforation which makes closure of the mucosal defect ideal to help prevent these complications. Case: A 56 year-old male with polycystic kidney disease underwent initial routine screening colonoscopy which revealed three polyps including an 18mm sessile polyp in the ascending colon which was not removed due to high risk of bleeding and perforation. A mucosal tattoo was placed and the patient returned for repeat colonoscopy with planned EMR of the remaining polyp. The lesion was raised using methylene blue and successfully removed en bloc using a braded snare. The resulting mucosal defect was severely angulated and attempts were made to close the defect using traditional through-the-scope clips. Upon deployment several clips broke while attempting to approximate the edges of the large defect. The colonoscope was withdrawn and a standard adult gastroscope was loaded with an 11mm cap/6mm depth over-the-scope clip (OTSC). The gastroscope was able to reach the ascending colon and provide better visualization en face. The OTSC was successfully deployed resulting in complete closure of the defect without any post-procedure bleeding or complication. Discussion: As use of EMR for removal of large mucosal neoplasms has become more widespread, it has revealed that through-the-scope clips are at times limited in their application by both width of coverage and force of closure which can result in multiple clips being deployed. This can significantly increase procedure time and expense for endoscopic intervention. Data for OTSC use in this setting is limited. Recent studies have shown successful prevention of secondary perforation and bleeding after EMR with the use of an OTSC, including a European study from 2016 which demonstrated 100% technical and clinical efficacy in 10 patients who experienced incomplete wall damage during EMR. Larger scale studies are needed to validate the technique, but this case report supports the claims of recent literature.Figure 1

OC-056 High Rate of Missed Visible Lesions in Patients Referred with Low Grade Dysplasia with Subsequent Upstaging of Pathology by EMR in Majority

Introduction Endoscopic therapy for Barrett’s oesophagus (BE) associated dysplasia or intramucosal cancer (IMC) has become the standard of care, and is recommended to occur in regional centres with high volume. Endoscopic mucosal resection (EMR) is often the first step as the majority of patients with high grade dysplasia (HGD) will have a visible lesion. This has been shown to upgrade HGD to more advanced pathology in over 30%. Little data exists on the use of EMR for low grade dysplasia (LGD). Aim of this study is to assess the rate of visible lesions in patients referred with LGD and outcomes of EMR. Methods Prospective study of patients undergoing BE dysplasia assessment at tertiary referral upper GI centre (GSTT). Surveillance endoscopy was performed with virtual chromoendoscopy (NBI) and conventional chromoendoscopy (acetic acid 2.5%) by two endoscopists, and EMR was undertaken, when feasible, to a visible lesion. Analysis was by independent t-tests for continuous variables and chi-squared tests for categorical variables. Results A total of 69 patients with BE underwent endoscopy, between 2014 and 2016. Results are shown in table 1. Patients were split into community pathology referral grade. There was no significant difference in patient’s age, sex or length of BE between the groups. EMR was undertaken to visible lesions in 84% of patients with HGD vs 54% with LGD. EMR was not performed due to advanced endoscopic lesions in 18% of patients referred with IMC, 13% with HGD and 4% for LGD. Pathology upstaging compared to the stage of the referring hospital was significantly higher in EMR specimens (50%) vs central pathology review of biopsies (19%) (p-value:0.001). There was no statistical difference in the rates of patients upstaged from EMR from patients referred with LGD vs HGD (64% vs 54%, p-value:0.75). In 3/26 (11%) of patients referred with LGD pathology of EMR specimen showed IMC. Conclusion This study demonstrates a high rate of missed visible lesions in patients diagnosed with LGD in a community setting, with half undergoing EMR. That these patients were upstaged to higher grades of dysplasia in 64% of the cases, indicates correct choice of EMR as a diagnostic modality in this group. Endoscopists carrying out surveillance endoscopy for patients with LGD should be aware of a high rate of visible lesions and advanced pathology, and consider referral to centre for further endoscopic evaluation. Disclosure of Interest None Declared

Predictors Of Treatment Failure After Radiofrequency Ablation For Intramucosal Adenocarcinoma in Barrett Esophagus: A Multi-institutional Retrospective Cohort Study.

Radiofrequency ablation (RFA), with or without endoscopic mucosal resection (EMR), is a safe, effective, and durable treatment option for Barrett esophagus (BE)-associated dysplasia (DYS), but few studies have identified predictors of treatment failure in BE-associated intramucosal adenocarcinoma (IMC). The aim of this study was to determine the rate of IMC eradication when using RFA±EMR and to identify clinical and pathologic predictors of treatment failure. A retrospective review of medical records and a central review of index histologic parameters were performed for 78 patients who underwent RFA±EMR as the primary treatment for biopsy-proven IMC at 4 academic tertiary medical centers. Complete eradication (CE) (absence of IMC/DYS on first follow-up endoscopy) was achieved in 86% of patients, and durable eradication (DE) (CE with no recurrence of IMC/DYS until last follow-up) was achieved in 78% of patients, with significant variation between the 4 study sites (P=0.03 and 0.09 by analysis of variance for DE and CE, respectively). Use of EMR before RFA significantly reduced the risk for treatment failure for IMC/DYS (hazard ratio, 0.15; 95% confidence interval, 0.05-0.48; P=0.001), whereas IMC involving ≥50% of the columnar metaplastic area on index examination significantly increased the risk for treatment failure (hazard ratio, 4.24; 95% confidence interval, 1.53-11.7; P=0.005). Endoscopic and pathologic factors associated with treatment failure in BE-associated IMC treated with RFA±EMR may help identify the subset of IMC patients for whom a more aggressive initial approach may be justified.

How to deal with large colorectal polyps: snare, endoscopic mucosal resection, and endoscopic submucosal dissection; resect or refer?

The importance of accurate polyp detection and removal is paramount to preventing colon cancer. Resection of large polyps can be challenging to the endoscopist based on their size, shape, or location. Large polyps have the potential of harboring malignancy and a higher risk of complications with resection. Careful assessment of each lesion and meticulous resection using the appropriate tools and techniques is essential. Over the last 15 years, the development of endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) techniques has presented the endoscopist with the opportunity to manage patients with large and flat lesions thereby avoiding the need for surgery. However, these techniques are complex and require extensive knowledge and skill in the use of various devices to resect a lesion completely and manage bleeding and perforation associated with these procedures. Large colon polyps manifest as either polypoid or nonpolypoid (flat) lesions. Polypoid lesions, especially those with pedicles, are removed with snare resection, whereas flat lesions may require the use of EMR or ESD. Resection of large polyps (>1 cm) requires additional tools and techniques to ensure safe and complete resection. We will discuss our approach to dealing with large colorectal polyps: snare, EMR, and ESD; resect or refer?

Endoscopic mucosal resection and endoscopic submucosal dissection in the treatment of sporadic nonampullary duodenal adenomatous polyps.

Although uncommon, sporadic nonampullary duodenal adenomas have a growing detection due to the widespread of endoscopy. Endoscopic therapy is being increasingly used for these lesions, since surgery, considered the standard treatment, carries significant morbidity and mortality. However, the knowledge about its risks and benefits is limited, which contributes to the current absence of standardized recommendations. This review aims to discuss the efficacy and safety of endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) in the treatment of these lesions. A literature review was performed, using the Pubmed database with the query: "(duodenum or duodenal) (endoscopy or endoscopic) adenoma resection", in the human species and in English. Of the 189 retrieved articles, and after reading their abstracts, 19 were selected due to their scientific interest. The analysis of their references, led to the inclusion of 23 more articles for their relevance in this subject. The increased use of EMR in the duodenum has shown good results with complete resection rates exceeding 80% and low complication risk (delayed bleeding in less than 12% of the procedures). Although rarely used in the duodenum, ESD achieves close to 100% complete resection rates, but is associated with perforation and bleeding risk in up to one third of the cases. Even though literature is insufficient to draw definitive conclusions, studies suggest that EMR and ESD are valid options for the treatment of nonampullary adenomas. Thus, strategies to improve these techniques, and consequently increase the effectiveness and safety of the resection of these lesions, should be developed.

PTU-172 Treatment Outcomes For Barrett’s Oesophagus Related Neoplasia Have Improved Over Time With Changes In Endoscopic Practice: Five Year Experience From The First Five Hundred Patients In The United Kingdom Registry

IntroductionBarrett’s oesophagus (BE) is the recognised pre-cursor to oesophageal adenocarcinoma (OAC). Combined endotherapy with endoscopic mucosal resection (EMR) and Radiofrequency ablation (RFA) have emerged as alternatives to surgery for curative...

Gender Differences in Remission of Esophageal Intestinal Metaplasia after Radiofrequency Ablation

Few studies have assessed the effect of gender on remission rates after radiofrequency ablation (RFA) of Barrett's esophagus (BE). We aim to assess the effect of gender on the time to achieve complete remission of intestinal metaplasia (CRIM) among patients with BE, who underwent RFA. This was a retrospective, observational study using a large RFA database in a tertiary referral center. The primary outcome was time to CRIM compared between males and females. Covariates included age, race, smoking history, use of endoscopic mucosal resection (EMR), histology before RFA, and the number of RFA sessions. Time to CRIM (in months) was calculated using the Kaplan-Meier method and compared using the log-rank test. Multivariable Cox-proportional hazard models were used to assess for any association between time to CRIM and gender. Two hundred and fifty-seven patients, 11% (n=23) female, underwent RFA for BE between May 2005 and June 2012. Males and females were similar in mean age, race, smoking history, median BE length, history of EMR, and baseline histology. Median time to CRIM for females was longer than males (24 months (95% confidence interval (CI): 10.3-60.2) vs. 11.7 months (95% CI: 10-15), P=0.03). Using Cox-regression analysis, controlling for age, use of EMR, BE segment length, and the number of RFA sessions, female gender was associated with a 55% decrease in the rate of CRIM compared with that in males (hazard ratio=0.45 (95% CI: 0.25-0.82), P=0.009). Females take longer time to achieve CRIM when treated with RFA when compared with males of similar age and BE length.

Gender Disparities in Remission of Esophageal Intestinal Metaplasia after Radio-frequency Ablation: ACG/Naomi Nakao Gender-Based Research Award

Purpose: Among the available ablative modalities, radiofrequency ablation (RFA) is the most commonly used for treatment of Barrett's esophagus (BE) with dysplasia. Few studies have assessed the effect of gender on remission rates after RFA. Preliminary studies indicate a potential biological difference between males and females with BE. We aim to assess the effect of gender on the time to achieve complete remission of intestinal metaplasia (CRIM) among patients with BE who underwent RFA. Methods: This was a retrospective, observational study using large RFA database in a tertiary referral center. The primary outcome was time to CRIM compared between males and females. Candidate predictor variables included patient age, sex, race, smoking history, use of endoscopic mucosal resection (EMR), and initial biopsy before RFA. Time to CRIM (in months) was calculated using the Kaplan-Meier method. Log-rank test was used for comparison. We used Multivariable cox-proportional hazard model to assess for any association between time to CRIM and predictor variables. Results: Two hundred fifty-seven patients underwent RFA for BE between May, 2005 and June, 2012. Of those, only 11% (n=26) were females. Males and females were similar in mean age, race, smoking history, median BE length, history of EMR, and baseline histology. Females required less RFA sessions compared to males (p=0.027). For males, median time to CRIM was 11.7 months [95% confidence interval [CI] 10 - 15]. For females, median time to CRIM was 24 months [95% CI 10.3 - 60.2]. The Log Rank χ2 statistic for the difference in time to CRIM was 4.7, with p=0.03. Kaplan-Meier curves of the time to CRIM stratified by gender are presented in Figure 1. Using cox-regression analysis, there was no evidence of confounding, collinearity, or effect modification in the final model. When controlling for age, use of EMR, BE segment length, and the number of RFA sessions, female gender was associated with 55% decrease in the rate of CRIM compared to males (HR = 0.45 [95% CI 0.25-0.82], p=0.009).FigureConclusion: Female patients take longer time to achieve remission of intestinal metaplasia when treated with radiofrequency ablation with or without endoscopic mucosal resection when compared to males of similar age and BE length. Further studies are needed to understand the potential factors leading to those important differences. Disclosure - Dr. Wolfsen is a consultant for CSA Medical, Ninepoint Medical, and Oncoscope. He receives research funding from BARRx Medical and Olympus America, Inc. Dr. Wallace is a consultant for Ninepoint Medical. He receives research funding from Olympus America, Inc, American BioOPTICS, and Fujinon.