Pancreatic necrosis: a scoping review.

Acute pancreatitis (AP) is a commonly encountered GI diagnosis, accounting for 275,000 hospital admissions annually in the United States alone. Pancreatic necrosis (PN) is the most common complication of AP, and the development of PN is associated with significant morbidity and increased mortality. This expert review evaluates the evidence-based management of symptomatic PN from the era of maximal open pancreatic necrosectomy in the late 1990s though the modern paradigm of minimally invasive and endoscopic interventions. The authors present the retrospective and controlled data behind the "step-up approach" to PN treatment and discuss the application of current society guidance. Evidence based management of PN is characterized by early supportive care, and treatment by minimally invasive intervention when a patient is critically ill or persistently symptomatic. Appropriate choices when intervention is required include percutaneous drainage, minimally invasive surgery, and/or endoscopic treatment. The transition from open maximal necrosectomy to minimally invasive intervention has resulted in improved outcomes for patients, including gains in mortality, significant morbidity, and cost. The ideal precision management strategy for an individual patient remains an area of increasing understanding.

Survival benefit associated with screening of patients at elevated risk for pancreatic cancer.

BACKGROUND & OBJECTIVES: Screening for pancreatic cancer is recommended for individuals with a strong family history, certain genetic syndromes, or a neoplastic cyst of the pancreas. However, limited data supports a survival benefit attributable to screening these higher-risk individuals. METHODS: All patients enrolled in screening at a High-Risk Pancreatic Cancer Clinic (HRC) from July 2013 to June 2020 were identified from a prospectively maintained institutional database and compared to patients evaluated at a Surgical Oncology Clinic (SOC) at the same institution during the same period. Clinical outcomes of patients selected for surgical resection, particularly clinicopathologic stage and overall survival, were compared. RESULTS: Among 826 HRC patients followed for a median (IQR) of 2.3 (0.8-4.2) years, 128 were selected for surgical resection and compared to 402 SOC patients selected for resection. Overall survival was significantly longer among HRC patients (median survival: not reached vs. 2.6 years, p < 0.001). Among 31 HRC and 217 SOC patients with a diagnosis of pancreatic ductal adenocarcinoma (PDAC), the majority of HRC patients were diagnosed with stage 0 disease (carcinoma in situ), while the majority of SOC patients were diagnosed with stage II disease (p < 0.001). Overall survival after resection of invasive PDAC was also significantly longer among HRC patients compared to SOC patients (median survival 5.5 vs. 1.6 years, p = 0.002). CONCLUSION: Patients at increased risk for PDAC and followed with guideline-based screening exhibited downstaging of disease and improved survival from PDAC in comparison to patients who were not screened.

Early safety of endoscopic sleeve gastroplasty in super obesity (body mass index > 50).

BACKGROUND: The prevalence of super obesity (body mass index [BMI] > 50) continues to rise. However, the adoption of bariatric surgery in this population remains very low. There are limited studies evaluating the utility of endoscopic sleeve gastroplasty (ESG) in super obesity. OBJECTIVES: The purpose of this study is to evaluate the short-term safety profile of ESG in patients with super obesity using data from the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program database. SETTING: United States. METHODS: We retrospectively analyzed patients who underwent ESG and sleeve gastrectomy (SG) from 2016 to 2021. Patients with BMI >50 who underwent ESG were compared to ESG patients with BMI <50 and also SG patients with BMI >50. Primary outcomes included the incidence of severe adverse events (AEs), hospital readmission, reintervention, and reoperation within 30 days of the primary procedure. Secondary outcomes included procedure time, hospital length of stay, and total body weight loss at 30 days. RESULTS: There were no significant differences in AE, reoperations, hospital readmissions, or reinterventions for patients with super obesity undergoing ESG, compared to patients with BMI below 50. Mean total body weight loss was greater in patients with super obesity. There were no significant differences in AEs for patients with super obesity who underwent ESG versus SG, although ESG patients had more hospital readmissions, reinterventions, and reoperations. CONCLUSIONS: ESG may be performed safely, with comparable safety to SG, in patients with BMI as high as 70. However, further studies are needed to validate the feasibility and long-term efficacy prior to clinical implementation.

Comparative accuracy of four guidelines to predict high-grade dysplasia or malignancy in surgically resected pancreatic intraductal papillary mucinous neoplasms: Small nuances between guidelines lead to vastly different results.

Backgrounds/Aims: The guidelines regarding the management of intraductal papillary mucinous neoplasms (IPMNs) all have slightly different surgical indications for high-risk lesions. We aim to retrospectively compare the accuracy of four guidelines in recommending surgery for high-risk IPMNs, and assess the accuracy of elevated CA-19-9 levels and imaging characteristics of IPMNs considered high-risk in predicting malignancy or high-grade dysplasia (HGD). Methods: The final histopathological diagnosis of surgically resected high-risk IPMNs during 2013-2020 were compared to preoperative surgical indications, as enumerated in four guidelines: the 2015 American Gastroenterological Association (AGA), 2017 International Consensus, 2018 European Study Group, and 2018 American College of Gastroenterology (ACG). Surgery was considered "justified" if histopathology of the surgical specimen showed HGD/malignancy, or there was postoperative symptomatic improvement. Results: Surgery was postoperatively justified in 26/65 (40.0%) cases. All IPMNs with HGD/malignancy were detected by the 2018 ACG and the combined (absolute and relative criteria) 2018 European guidelines. The combined ("high-risk stigmata" and "worrisome features") 2017 International guideline missed 1/19 (5.3%) IPMNs with HGD/malignancy. The 2015 AGA guideline missed the most cases (11/19, 57.9%) of IPMNs with HGD/malignancy. We found the features most-associated with HGD/malignancy were pancreatic ductal dilation, and elevated CA-19-9 levels. Conclusions: Following the 2015 AGA guideline results in the highest rate of missed HGD/malignancy, but the lowest rate of operating on IPMNs without these features; meanwhile, the 2018 ACG and the combined (absolute and relative criteria) 2018 European guidelines result in more operations for IPMNs without HGD/malignancy, but the lowest rates of missed HGD/malignancy in IPMNs.

Endoscopic Management of Pain due to Chronic Pancreatitis.

Pain secondary to chronic pancreatitis is a poorly understood and complex phenomenon. Current endoscopic treatments target pancreatic duct decompression secondary to strictures, stones, or inflammatory and neoplastic masses. When there is refractory pain and other treatments have been unsuccessful, one can consider an endoscopic ultrasound-guided celiac plexus block. Data on the latter are underwhelming.

Increased rate of pancreatitis in gender diverse and transgender patients on hormone therapy: a case series study.

BACKGROUND: There is limited data on the incidence of gastrointestinal-specific pathology in gender non-conforming (GNC) populations. METHODS: Retrospective analysis of pancreatitis incidence rates in transgender and GNC persons exposed and not exposed to gender-affirming hormone therapy (GAHT). RESULTS: 7 of the 1333 patients on hormone therapy had an incidence of pancreatitis. 0 of the 615 patients with no history of GAHT use developed pancreatitis. Representing a 6.96 (95% CI 2.76 to 848.78) for the development of pancreatitis in patients with exposure to GAHT therapy. CONCLUSION: Clinicians working with GNC individuals should be aware of this possible association.

Associations between income and survival in cholangiocarcinoma: A comprehensive subtype-based analysis.

Backgrounds/Aims: Socioeconomic determinants of health are incompletely characterized in cholangiocarcinoma (CCA). We assessed how socioeconomic status influences initial treatment decisions and survival outcomes in patients with CCA, additionally performing multiple sub-analyses based on anatomic location of the primary tumor. Methods: Observational study using the 2018 submission of the Surveillance, Epidemiology, and End Results (SEER)-18 Database. In total, 5,476 patients from 2004-2015 with a CCA were separated based on median household income (MHI) into low income (< 25th percentile of MHI) and high income (> 25th percentile of MHI) groups. Seventy-three percent of patients had complete follow up data, and were included in survival analyses. Survival and treatment outcomes were calculated using R-studio. Results: When all cases of CCA were included, the high-income group was more likely than the low-income to receive surgery, chemotherapy, and local tumor destruction modalities. Initial treatment modality based on income differed significantly between tumor locations. Patients of lower income had higher overall and cancer-specific mortality at 2 and 5 years. Non-cancer mortality was similar between the groups. Survival differences identified in the overall cohort were maintained in the intrahepatic CCA subgroup. No differences between income groups were noted in cancer-specific or overall mortality for perihilar tumors, with variable differences in the distal cohort. Conclusions: Lower income was associated with higher rates of cancer-specific mortality and lower rates of surgical resection in CCA. There were significant differences in treatment selection and outcomes between intrahepatic, perihilar, and distal tumors. Population-based strategies aimed at identifying possible etiologies for these disparities are paramount to improving patient outcomes.

Evolution of interventional endoscopic ultrasound.

Endoscopic ultrasound (EUS) has become an indispensable modality for the assessment of the gastrointestinal tract and adjacent structures since its origin in the 1980s. Following the development of the linear echoendoscope, EUS has evolved from a purely diagnostic modality to a sophisticated tool for intervention, with numerous luminal, pancreaticobiliary, and hepatic applications. Broadly, these applications may be subdivided into three categories: transluminal drainage or access procedures, injection therapy, and EUS-guided liver interventions. Transluminal drainage or access procedures include management of pancreatic fluid collection, EUS-guided biliary drainage, EUS-guided bile duct drainage, EUS-guided pancreatic duct drainage, and enteral anastomosis formation. Injection therapies include therapeutic EUS-guided injections for management of malignancies accessible by EUS. EUS-guided liver applications include EUS-guided liver biopsy, EUS-guided portal pressure gradient measurement, and EUS-guided vascular therapies. In this review, we discuss the origins of each of these EUS applications, evolution of techniques leading to the current status, and future directions of EUS-guided interventional therapy.

Socioeconomic Disparities Affect Outcomes in Early-Stage Esophageal Adenocarcinoma: A SEER Analysis.

BACKGROUND & AIMS: Socioeconomic determinants of health are understudied in early stage esophageal adenocarcinoma. We aimed to assess how socioeconomic status influences initial treatment decisions and survival outcomes in patients with T1a esophageal adenocarcinoma. METHODS: We performed an observational study using the 2018 submission of the Surveillance, Epidemiology, and End Results-18 database. A total of 1526 patients from 2004 to 2015 with a primary T1aN0M0 esophageal adenocarcinoma were subdivided into 3 socioeconomic tertiles based on their median household income. Endoscopic trends over time, rates of endoscopic and surgical treatment, 2- and 5-year overall survival, cancer-specific mortality, and non-cancer-specific mortality were calculated. Statistical analysis was performed using R-studio. RESULTS: Patients within the lowest median household income tertile ($20,000-$54,390) were associated with higher cancer-specific mortality at 2 years (P < .01) and 5 years (P < .02), and lower overall survival at 2 and 5 years (P < .01) compared with patients in higher income tertiles. Patients with a higher income had a decreased hazard ratio for cancer-specific mortality (hazard ratio, 0.66; 95% CI, 0.45-0.99) in a multivariate Cox proportional hazards regression model. Patients within the higher income tertile were more likely to receive endoscopic intervention (P < .001), which was associated with improved cancer-specific mortality compared with patients who received primary surgical intervention (P = .001). The South had lower rates of endoscopy compared with other regions. CONCLUSIONS: Lower median household income was associated with higher rates of cancer-specific mortality and lower rates of endoscopic resection in T1aN0M0 esophageal adenocarcinoma. Population-based strategies aimed at identifying and rectifying possible etiologies for these socioeconomic and geographic disparities are paramount to improving patient outcomes in early esophageal cancer.

Comparison of endoscopic sleeve gastroplasty versus surgical sleeve gastrectomy: a Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program database analysis.

BACKGROUND AND AIMS: Endoscopic sleeve gastroplasty (ESG) is an incisionless, transoral, restrictive bariatric procedure designed to imitate sleeve gastrectomy (SG). Comparative studies and large-scale population-based data are limited. Additionally, no studies have examined the impact of race on outcomes after ESG. This study aims to compare short-term outcomes of ESG with SG and evaluate racial effects on short-term outcomes after ESG. METHODS: We retrospectively analyzed over 600,000 patients in the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program database from 2016 to 2020. We compared occurrences of adverse events (AEs), readmissions, reoperations, and reinterventions within 30 days after procedures. Multivariate regression evaluated the impact of patient factors, including race, on AEs. RESULTS: A total of 6054 patients underwent ESG and 597,463 underwent SG. AEs were low after both procedures with no significant difference in major AEs (SG vs ESG: 1.1% vs 1.4%; P > .05). However, patients undergoing ESG had more readmissions (3.8% vs 2.6%), reoperations (1.4% vs .8%), and reinterventions (2.8% vs .7%) within 30 days (P < .05). Race was not significantly associated with AEs after ESG, with black race associated with a higher risk of AEs in SG. CONCLUSIONS: ESG demonstrates a comparable major AE rate with SG. Race did not impact short-term AEs after ESG. Further prospective studies long-term studies are needed to compare ESG with SG.

AGA Clinical Practice Update on the Endoscopic Approach to Recurrent Acute and Chronic Pancreatitis: Expert Review.

DESCRIPTION: The purpose of this American Gastroenterological Association (AGA) Clinical Practice Update Expert Review is to provide practical, evidence-based guidance to clinicians regarding the role of endoscopy for recurrent acute and chronic pancreatitis. METHODS: This expert review was commissioned and approved by the AGA Institute Clinical Practice Updates Committee and the AGA Governing Board to provide guidance on a topic of clinical importance to the AGA membership, underwent internal peer review by the Clinical Practice Updates Committee (CPUC), and external peer review through standard procedures of Gastroenterology. This review is framed around the 8 best practice advice points agreed upon by the authors, based on the results of randomized controlled trials, observational studies, systematic reviews and meta-analyses, as well expert consensus in this field. Best Practice Advice Statements BEST PRACTICE ADVICE 1: After an unrevealing initial evaluation, endoscopic ultrasound is the preferred diagnostic test for unexplained acute and recurrent pancreatitis. Magnetic resonance imaging with contrast and cholangiopancreatography is a reasonable complementary or alternative test to endoscopic ultrasound, based on local expertise and availability. BEST PRACTICE ADVICE 2: The role of endoscopic retrograde cholangiopancreatography (ERCP) for reducing the frequency of acute pancreatitis episodes in patients with pancreas divisum is controversial, but minor papilla endotherapy may be considered, particularly for those with objective signs of outflow obstruction, such as a dilated dorsal pancreatic duct and/or santorinicele. There is no role for ERCP to treat pain alone in patients with pancreas divisum. BEST PRACTICE ADVICE 3: The role of ERCP for reducing the frequency of pancreatitis episodes in patients with unexplained recurrent acute pancreatitis and standard pancreatic ductal anatomy is controversial and should only be considered after a comprehensive discussion of the uncertain benefits and potentially severe procedure-related adverse events. When pursued, ERCP with biliary sphincterotomy alone may be preferable to dual sphincterotomy. BEST PRACTICE ADVICE 4: Surgical intervention should be considered over endoscopic therapy for long-term treatment of patients with painful obstructive chronic pancreatitis. Endoscopic intervention is a reasonable alternative to surgery for suboptimal operative candidates or those who favor a less invasive approach, assuming they are clearly informed that the best practice advice primarily favors surgery. BEST PRACTICE ADVICE 5: When ERCP is pursued, small (≤5mm) main pancreatic duct stones can be treated with pancreatography and conventional stone extraction maneuvers. For larger stones, extracorporeal shockwave lithotripsy and/or pancreatoscopy with intraductal lithotripsy may be required. BEST PRACTICE ADVICE 6: When ERCP is pursued, prolonged stent therapy (6-12 months) is effective for treating symptoms and remodeling main pancreatic duct strictures. The preferred approach is to place and sequentially add multiple plastic stents in parallel (upsizing); emerging evidence suggests that fully covered self-expanding metal stents may have a role for this indication, but additional research is necessary. BEST PRACTICE ADVICE 7: ERCP with stent insertion is the preferred treatment for benign biliary stricture due to chronic pancreatitis. FCSEMS placement is favored over multiple plastic stents whenever feasible, given similar efficacy but significantly reduced need for stent exchange procedures during the treatment course. BEST PRACTICE ADVICE 8: Celiac plexus block should not be routinely performed for the management of pain due to chronic pancreatitis. The decision to proceed with celiac plexus block in selected patients with debilitating pain in whom other therapeutic measures have failed can be considered on a case-by-case basis, but only after discussion of the unclear outcomes of this intervention and its procedural risks.

Endoscopic Ultrasound-guided Fine-needle Biopsy With or Without Rapid On-site Evaluation for Diagnosis of Solid Pancreatic Lesions: A Randomized Controlled Non-Inferiority Trial.

BACKGROUND AND AIMS: The benefit of rapid on-site evaluation (ROSE) on the diagnostic accuracy of endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) has never been evaluated in a randomized study. This trial aimed to test the hypothesis that in solid pancreatic lesions (SPLs), diagnostic accuracy of EUS-FNB without ROSE was not inferior to that of EUS-FNB with ROSE. METHODS: A noninferiority study (noninferiority margin, 5%) was conducted at 14 centers in 8 countries. Patients with SPLs requiring tissue sampling were randomly assigned (1:1) to undergo EUS-FNB with or without ROSE using new-generation FNB needles. The touch-imprint cytology technique was used to perform ROSE. The primary endpoint was diagnostic accuracy, and secondary endpoints were safety, tissue core procurement, specimen quality, and sampling procedural time. RESULTS: Eight hundred patients were randomized over an 18-month period, and 771 were analyzed (385 with ROSE and 386 without). Comparable diagnostic accuracies were obtained in both arms (96.4% with ROSE and 97.4% without ROSE, P = .396). Noninferiority of EUS-FNB without ROSE was confirmed with an absolute risk difference of 1.0% (1-sided 90% confidence interval, -1.1% to 3.1%; noninferiority P < .001). Safety and sample quality of histologic specimens were similar in both groups. A significantly higher tissue core rate was obtained by EUS-FNB without ROSE (70.7% vs. 78.0%, P = .021), with a significantly shorter mean sampling procedural time (17.9 ± 8.8 vs 11.7 ± 6.0 minutes, P < .0001). CONCLUSIONS: EUS-FNB demonstrated high diagnostic accuracy in evaluating SPLs independently on execution of ROSE. When new-generation FNB needles are used, ROSE should not be routinely recommended. (ClinicalTrial.gov number NCT03322592.).

Development of an automated ERCP Quality Report Card using structured data fields.

BACKGROUND AND AIMS: Measuring adherence to ERCP quality indicators (QIs) is confounded by variability in indications, maneuvers, and documentation styles. We hypothesized that incorporation of mandatory, structured data fields within reporting software would permit accurate measurement of QI adherence rates and facilitate generation of a provider ERCP report card. METHODS: At two referral centers, endoscopy documentation software was modified to generate provider alerts prior to finalizing the note. The alerts reminded the provider to document the following components in a standardized manner: indication, altered anatomy, prior interventions, and QIs deemed high priority by society consensus, study authors, or both. Adherence rates for each QI were calculated in aggregate and by provider via data extraction directly from the procedure documentation software. Medical records were reviewed manually to measure the accuracy of automated data extraction. Accuracy of automated measurement for each QI was calculated against results derived by manual review. RESULTS: During the 9-month study period, 1,376 ERCP procedures were completed by 8 providers. Manual medical record review confirmed high (98-100%) accuracy of automatic extraction of ERCP QIs from the endoscopy report, including cannulation rate of the native papilla and complete extraction of common bile duct stones. An ERCP report card was generated, allowing for individual comparison of adherence to ERCP QIs with colleagues at their institution and others. CONCLUSION: In this pilot study, use of mandatory, structured data fields within clinical ERCP reports permit the accurate measurement of high priority ERCP QIs and the subsequent generation of interval report cards.

Safety and rate of delayed adverse events with lumen-apposing metal stents (LAMS) for pancreatic fluid collections: a multicenter study.

Background and study aims Endoscopic drainage with dedicated lumen-apposing metal stents (LAMS) is routinely performed for symptomatic pancreatic fluid collections (PFCs), walled-off necrosis (WON) and pseudocyst (PP). There has been increasing concern regarding delayed adverse events associated with the indwelling LAMS.  Patients and methods Multicenter retrospective analysis of consecutive patients who underwent endoscopic ultrasound (EUS)-guided LAMS placement for PFC from January 2010 to May 2017. Main outcomes included: (1) resolution of the PFC, (2) rate of delayed adverse events at follow-up, and (3) predictors of treatment failure and delayed adverse events on logistic regression. Results A total of 122 patients (mean age 50.9 years, 68 % male) underwent LAMS insertion for 64 WON (98.4 %) and 58 PP (98.3 %). PFC mean size was 10.6 cm. PFC resolution was significantly lower for WON (62.3 %) vs. PP (96.5 %) ( P  < 0.001) on imaging at a median of 4 weeks. Stent occlusion was identified in 18 (29.5 %) and 10 (17.5 %) patients with WON and PP, respectively ( P  = 0.13). There were no cases of delayed bleeding or buried stent on follow-up endoscopy. Use of electrocautery-enhanced LAMS was the only factor associated with treatment failure of WON (OR = 13.2; 95 % ci: 3.33 - 51.82, P  = 0.02) on logistic regression. There were no patient, operator, or procedure-related factors predictive of stent occlusion. Conclusions EUS-guided LAMS for PFC is associated with a low incidence of delayed adverse events. While nearly all PPs resolve at 4 weeks permitting LAMS removal shortly thereafter, many WON persist, with use of electrocautery-enhanced LAMS being the sole predictor of treatment failure.

Efficacy and Safety of Digital Single-Operator Cholangioscopy for Difficult Biliary Stones.

BACKGROUND & AIMS: It is not clear whether digital single-operator cholangioscopy (D-SOC) with electrohydraulic and laser lithotripsy is effective in removal of difficult biliary stones. We investigated the safety and efficacy of D-SOC with electrohydraulic and laser lithotripsy in an international, multicenter study of patients with difficult biliary stones. METHODS: We performed a retrospective analysis of 407 patients (60.4% female; mean age, 64.2 years) who underwent D-SOC for difficult biliary stones at 22 tertiary centers in the United States, United Kingdom, or Korea from February 2015 through December 2016; 306 patients underwent electrohydraulic lithotripsy and 101 (24.8%) underwent laser lithotripsy. Univariate and multivariable analyses were performed to identify factors associated with technical failure and the need for more than 1 D-SOC electrohydraulic or laser lithotripsy session to clear the bile duct. RESULTS: The mean procedure time was longer in the electrohydraulic lithotripsy group (73.9 minutes) than in the laser lithotripsy group (49.9 minutes; P < .001). Ducts were completely cleared (technical success) in 97.3% of patients (96.7% of patients with electrohydraulic lithotripsy vs 99% patients with laser lithotripsy; P = .31). Ducts were cleared in a single session in 77.4% of patients (74.5% by electrohydraulic lithotripsy and 86.1% by laser lithotripsy; P = .20). Electrohydraulic or laser lithotripsy failed in 11 patients (2.7%); 8 patients were treated by surgery. Adverse events occurred in 3.7% patients and the stone was incompletely removed from 6.6% of patients. On multivariable analysis, difficult anatomy or cannulation (duodenal diverticula or altered anatomy) correlated with technical failure (odds ratio, 5.18; 95% confidence interval, 1.26-21.2; P = .02). Procedure time increased odds of more than 1 session of D-SOC electrohydraulic or laser lithotripsy (odds ratio, 1.02; 95% confidence interval, 1.01-1.03; P < .001). CONCLUSIONS: In a multicenter, international, retrospective analysis, we found D-SOC with electrohydraulic or laser lithotripsy to be effective and safe in more than 95% of patients with difficult biliary stones. Fewer than 5% of patients require additional treatment with surgery and/or extracorporeal shockwave lithotripsy to clear the duct.

Operative management of chronic pancreatitis: A review.

BACKGROUND: Pain secondary to chronic pancreatitis is a difficult clinical problem to manage. Many patients are treated medically or undergo endoscopic therapy and surgical intervention is often reserved for those who have failed to gain adequate pain relief from a more conservative approach. RESULTS: There have been a number of advances in the operative management of chronic pancreatitis over the last few decades and current therapies include drainage procedures (pancreaticojejunostomy, etc.), resection (pancreticoduodenectomy, etc.) and combined drainage/resection procedures (Frey procedure, etc.). Additionally, many centers currently perform total pancreatectomy with islet autotransplantation, in addition to minimally invasive options that are intended to tailor therapy to individual patients. DISCUSSION: Operative management of chronic pancreatitis often improves quality of life, and is associated with low rates of morbidity and mortality. The decision as to which procedure is optimal for each patient should be based on a combination of pathologic changes, prior interventions, and individual surgeon and center experience.

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

BACKGROUND: Studies comparing the efficacy and safety of conventional saline-assisted piecemeal endoscopic mucosal resection (EMR) to underwater EMR (UEMR) without submucosal lifting of colorectal polyps are lacking. The objective of this study was to compare the efficacy and safety of EMR to UEMR of large colorectal polyps. METHODS: Two hundred eighty-nine colorectal polyps were removed by a single endoscopist from 7/2007 to 2/2015 using EMR or UEMR. 135 polyps (EMR: 62, UEMR: 73) that measured ≥15 mm and had not undergone prior attempted polypectomy were evaluated for rates of complete macroscopic resection and adverse events. 101 of these polyps (EMR: 46, UEMR: 55) had at least 1 follow-up colonoscopy and were studied for rates of recurrence and the number of procedures required to achieve curative resection. RESULTS: The rate of complete macroscopic resection was higher following UEMR compared to EMR (98.6 vs. 87.1%, p = 0.012). UEMR had a lower recurrence rate at the first follow-up colonoscopy compared to EMR (7.3 vs. 28.3%, OR 5.0 for post-EMR recurrence, 95% CI: [1.5, 16.5], p = 0.008). UEMR required fewer procedures to reach curative resection than EMR (mean of 1.0 vs. 1.3, p = 0.002). There was no significant difference in rates of adverse events. CONCLUSIONS: UEMR appears superior to EMR for the removal of large colorectal polyps in terms of rates of complete macroscopic resection and recurrent (or residual) abnormal tissue. Compared to conventional EMR, UEMR may offer increased procedural effectiveness without compromising safety in the removal of large colorectal polyps without prior attempted resection.