Proceedings from the First Global Artificial Intelligence in Gastroenterology and Endoscopy Summit.

BACKGROUND AND AIMS: Artificial intelligence (AI), specifically deep learning, offers the potential to enhance the field of GI endoscopy in areas ranging from lesion detection and classification to quality metrics and documentation. Progress in this field will be measured by whether AI implementation can lead to improved patient outcomes and more efficient clinical workflow for GI endoscopists. The aims of this article are to report the findings of a multidisciplinary group of experts focusing on issues in AI research and applications related to gastroenterology and endoscopy, to review the current status of the field, and to produce recommendations for investigators developing and studying new AI technologies for gastroenterology. METHODS: A multidisciplinary meeting was held on September 28, 2019, bringing together academic, industry, and regulatory experts in diverse fields including gastroenterology, computer and imaging sciences, machine learning, computer vision, U.S. Food and Drug Administration, and the National Institutes of Health. Recent and ongoing studies in gastroenterology and current technology in AI were presented and discussed, key gaps in knowledge were identified, and recommendations were made for research that would have the highest impact in making advances and implementation in the field of AI to gastroenterology. RESULTS: There was a consensus that AI will transform the field of gastroenterology, particularly endoscopy and image interpretation. Powered by advanced machine learning algorithms, the use of computer vision in endoscopy has the potential to result in better prediction and treatment outcomes for patients with gastroenterology disorders and cancer. Large libraries of endoscopic images, "EndoNet," will be important to facilitate development and application of AI systems. The regulatory environment for implementation of AI systems is evolving, but common outcomes such as colon polyp detection have been highlighted as potential clinical trial endpoints. Other threshold outcomes will be important, as well as clarity on iterative improvement of clinical systems. CONCLUSIONS: Gastroenterology is a prime candidate for early adoption of AI. AI is rapidly moving from an experimental phase to a clinical implementation phase in gastroenterology. It is anticipated that the implementation of AI in gastroenterology over the next decade will have a significant and positive impact on patient care and clinical workflows. Ongoing collaboration among gastroenterologists, industry experts, and regulatory agencies will be important to ensure that progress is rapid and clinically meaningful. However, several constraints and areas will benefit from further exploration, including potential clinical applications, implementation, structure and governance, role of gastroenterologists, and potential impact of AI in gastroenterology.

A utility of peroral endoscopic myotomy (POEM) across the spectrum of esophageal motility disorders.

BACKGROUND: Peroral endoscopic myotomy (POEM) has been performed as a novel endoscopic procedure to treat achalasia with favorable outcome. The objective of this study was to assess the outcome of POEM in our initial series and to assess the safety and efficacy of POEM in a variety of esophageal motility-related clinical problems. METHODS: This is a retrospective cross-sectional study involving all patients with esophageal motility disorders defined by the Chicago classification, who had undergone consideration for POEM at our institution. Validated questionnaires such as gastroesophageal reflux disease health-related quality of life (GERD-HRQL), reflux symptom index (RSI) and achalasia disease-specific health-related quality of life were obtained pre- and postoperatively. RESULTS: From January 2013 to October 2014, a total of 35 POEMs (achalasia n = 25, non-achalasia n = 10) were performed on 33 patients (female n = 20, male n = 13, mean age 56.9 years). There was no mortality. The rate of inadvertent mucosotomy was 17.1%. The rate of complications requiring interventions was 5.7%. During a mean follow-up period of 7 months (range 0.5-17), 92% of patients with achalasia and 75% of those with non-achalasia motility disorders had a symptomatic improvement in dysphagia. Chest pain was completely resolved in all patients with achalasia (8/8) and 80% of patients with non-achalasia (4/5). The GERD-HRQL, RSI and dysphagia scores significantly improved after POEM in patients with achalasia. There was a significant improvement in GERD-HRQL and RSI scores, and a trend toward lower dysphagia score in patients with non-achalasia. CONCLUSIONS: The outcome of POEM to treat achalasia and non-achalasia motility disorders is consistent with previous studies. Potential benefit of POEM includes not only its flexibility to adjust the length and location of myotomy but also the ability to extend myotomy proximally without thoracoscopy or thoracotomy. POEM can be combined with laparoscopic procedures and used as "salvage" for localized esophageal dysmotility.

MicroRNA signature characterizes primary tumors that metastasize in an esophageal adenocarcinoma rat model.

OBJECTIVE: To establish a miRNA signature for metastasis in an animal model of esophageal adenocarcinoma (EAC). BACKGROUND: The incidence of esophageal adenocarcinoma (EAC) has dramatically increased and esophageal cancer is now the sixth leading cause of cancer deaths worldwide. Mortality rates remain high among patients with advanced stage disease and esophagectomy is associated with high complication rates. Hence, early identification of potentially metastatic disease would better guide treatment strategies. METHODS: The modified Levrat's surgery was performed to induce EAC in Sprague-Dawley rats. Primary EAC and distant metastatic sites were confirmed via histology and immunofluorescence. miRNA profiling was performed on primary tumors with or without metastasis. A unique subset of miRNAs expressed in primary tumors and metastases was identified with Ingenuity Pathway Analysis (IPA) along with upstream and downstream targets. miRNA-linked gene expression analysis was performed on a secondary cohort of metastasis positive (n=5) and metastasis negative (n=28) primary tumors. RESULTS: The epithelial origin of distant metastasis was established by IF using villin (VIL1) and mucin 5AC (MUC5AC) antibodies. miRNome analysis identified four down-regulated miRNAs in metastasis positive primary tumors compared to metastasis negative tumors: miR-92a-3p (p=0.0001), miR-141-3p (p=0.0022), miR-451-1a (p=0.0181) and miR133a-3p (p=0.0304). Six target genes identified in the top scoring networks by IPA were validated as significantly, differentially expressed in metastasis positive primary tumors: Ago2, Akt1, Kras, Bcl2L11, CDKN1B and Zeb2. CONCLUSION: In vivo metastasis was confirmed in the modified Levrat's model. Analysis of the primary tumor identified a distinctive miRNA signature for primary tumors that metastasized.

Intraductal oncocytic papillary neoplasm of the pancreas: a case of a second neoplasm in a pancreas cancer survivor.

CONTEXT: Cystic neoplasms, which are less common forms of exocrine pancreatic neoplasms, consist of mainly intraductal papillary mucinous neoplasms (IPMN) and mucinous cystic neoplasms. Mucinous cystic neoplasms, unlike IPMN, are not associated with ductal growth, are usually multilocular in nature, and have ovarian type stroma. Mucinous cystadenocarcinoma is a type of mucinous cystic neoplasm more commonly found in women. Intraductal oncocytic papillary neoplasms of the pancreas are the least common variant of IPMN. Despite this classification, intraductal oncocytic papillary neoplasms have been compared to mucinous cystic neoplasms in previous studies and the classification is still questioned. CASE REPORT: We report a rare case of an intraductal oncocytic papillary neoplasm of the pancreas occurring in a 52-year-old male with a prior history of surgically excised mucinous cystadenocarcinoma. This is the first known case of an intraductal oncocytic papillary neoplasm occurring after a prior pancreatic neoplasm. CONCLUSIONS: As the diagnosis of intraductal oncocytic papillary neoplasms are rare, having only a few case reports and small series on which to understand its disease process, it is imperative to discuss each case and detail possible correlations with other pancreatic cystic neoplasms as well as distinctions from its current association within IPMN.

A multicenter, U.S. experience of single-balloon, double-balloon, and rotational overtube-assisted enteroscopy ERCP in patients with surgically altered pancreaticobiliary anatomy (with video).

BACKGROUND: Data on overtube-assisted enteroscopy to facilitate ERCP in patients with surgically altered pancreaticobiliary anatomy, or long-limb surgical bypass, is limited. OBJECTIVE: To evaluate and compare ERCP success by using single-balloon (SBE), double-balloon (DBE), or rotational overtube enteroscopy. DESIGN: Consecutive patients identified retrospectively. SETTING: Eight U.S. referral centers. PATIENTS: Long-limb surgical bypass patients with suspected pancreaticobiliary diseases. INTERVENTION: Overtube-assisted enteroscopy ERCP. MAIN OUTCOME MEASUREMENTS: Enteroscopy success: visualizing the pancreaticobiliary-enteric anastomosis or papilla. ERCP success: completing the intended pancreaticobiliary intervention. Clinical success: greater than 50% reduction in abdominal pain or level of hepatic enzyme elevations or resolution of jaundice. RESULTS: From January 2008 through October 2009, 129 patients had 180 enteroscopy-ERCPs. Anatomy was Roux-en-Y: gastric bypass (n = 63), hepaticojejunostomy (n = 45), postgastrectomy (n = 6), Whipple procedure (n = 10), and other (n = 5). ERCP success was 81 of 129 (63%). Enteroscopy success: 92 of 129 (71%), of whom 81 of 92 (88%) achieved ERCP success. Reasons for ERCP failure (n = 48): afferent limb entered but pancreaticobiliary anastomosis and/or papilla not reached (n = 23), cannulation failure (n = 11), afferent limb angulation (n = 8), and jejunojejunostomy not identified (n = 6). Select interventions: anastomotic stricturoplasty (cautery ± dilation, n = 16), stone removal (n = 21), stent (n = 25), and direct cholangioscopy (n = 11). ERCP success rates were similar between Roux-en-Y gastric bypass and other long-limb surgical bypass and among SBE, DBE, and rotational overtube enteroscopy. Complications were 16 of 129, 12.4%. LIMITATIONS: Retrospective study. CONCLUSION: (1) ERCP is successful in nearly two-thirds of long-limb surgical bypass patients and in 88% when the papilla or pancreaticobiliary-enteric anastomosis is reached. (2) Enteroscopy success in long-limb surgical bypass is similar among SBE, DBE, and rotational overtube enteroscopy methods. (3) Referral of long-limb surgical bypass patients who require ERCP to high-volume institutions may be considered before more invasive percutaneous or surgical alternatives.

Correlation of the presence and extent of loss of heterozygosity mutations with histological classifications of Barrett's esophagus.

BACKGROUND: Recent advances in the management of Barrett's Esophagus (BE) have placed greater emphasis on accurate diagnosis of BE as well as better prediction of risk for progression to esophageal adenocarcinoma (EAC). Histological evaluation of BE is particularly challenging with significant inter-observer variability. We explored the presence and extent of genomic instability in BE biopsy specimens as a means to add supplementary information to the histological classification and clinical decision-making related to early disease. METHODS: We reviewed histology slides from 271 patients known to have BE. Using histological features as a guide, we microdissected target cell populations with various histological classifications of BE (intestinal metaplasia, "indefinite for dysplasia", low grade dysplasia, or high grade dysplasia). DNA was extracted from microdissected targets and analyzed for loss of heterozygosity (LOH) using a panel of 16 LOH mutational markers associated with tumor suppressor genes at chromosomal loci 1p, 3p, 5q, 9p, 10q, 17p, 17q, 18q, 21q, 22q. The presence or absence of mutations and the clonality of each mutation were determined for each marker. RESULTS: The presence and clonal expansion of LOH mutations was formulated into mutational load (ML) for each microdissected target analyzed. ML correlated with the histological classification of microdissected targets, with increasingly severe histology having higher ML. Three levels of mutation load (no ML, low ML, and high ML) were defined based on the population of microdissected targets histologically classified as intestinal metaplasia. All microdissected targets with dysplasia had mutations, with a high ML consistently present in high grade dysplasia targets. Microdissected targets histologically classified as intestinal metaplasia or "indefinite for dysplasia" spanned a range of no, low, and high ML. CONCLUSIONS: The results of this study reinforce the association of genomic instability with disease progression in BE. The presence and extent (clonality) of genomic instability, as assessed by mutational load, may assist histology in defining early stages of BE that are potentially at greater risk for disease progression. Assessment of mutational load using our panel of LOH mutational markers may be a useful adjunct to microscopic inspection of biopsy specimens, and thereby, improve patient management.

Development of a pancreatic tumor animal model and evaluation of NOTES tumor enucleation.

BACKGROUND: Laparoscopic distal pancreatectomy is associated with high morbidity and mortality. NOTES tumor enucleation may provide an alternative to laparoscopic distal pancreatectomy. The goal of this study was to determine the feasibility of NOTES tumor creation and enucleation as a multidisciplinary approach. METHODS: A linear-array endoscopic ultrasound (EUS) endoscope was used to inject a thermosensitive ABA triblock polymer mixed with methylene blue through the stomach wall and into the distal pancreas using a 22-gauge EUS needle. Due to its thermosensitive character, the polymer solidifies in response to body temperature, creating an artificial tumor. Seventeen swine underwent NOTES transgastric pancreatic tumor enucleation. Nine nonsurvival animals were sacrificed immediately after the NOTES procedure, with subsequent necropsy. Eight survival animals were observed for up to 16 days after the procedure, subsequently sacrificed, followed by necropsy. RESULTS: The procedure was performed successfully in all 17 pigs studied, 9/9 nonsurvival (100%) and 8/8 survival (100%) animals, using a pure NOTES approach without any laparoscopic ports. Complications included two esophageal dissections (1 in nonsurvival group, 1 in survival group) caused by the introduction of the endoscopic overtube (2/17, 12%), unrelated to the actual surgical procedure. In the survival animals, there were two small splenic lacerations caused during retraction with the endoscopic forceps, for which hemostasis was achieved prior to closure of the gastrotomy (2/7, 29%). At necropsy of the animals, there was sufficient closure of 15/17 gastrotomy sites (88%). CONCLUSIONS: The creation of artificial pancreatic tumors via EUS guidance is feasible. Pancreatic tumor enucleation using a transgastric NOTES approach is technically feasible and could be an alternative to laparoscopic distal pancreatectomy with further development. Further adoption and adaptation of this technique will require the development of more sophisticated specialized tools to improve the safety profile of the procedure.

Retroperitoneal leiomyosarcoma presenting as lower gastrointestinal bleeding: a case report and review of the literature.

We report the first known case of a retroperitoneal leiomyosarcoma that presented with an endoscopically defined source of gastrointestinal bleeding in the colon. A 68-year-old male with a history of diverticulosis, hypertension, and hypercholesterolemia who complained of a 3-month history of abdominal pain, nausea, and intermittent hematochezia presented for evaluation of large volume hematochezia and lightheadedness. Colonoscopy revealed left-sided diverticulosis and rectal varices without stigmata of recent bleed. CT scan showed a 26 × 20 × 13 cm heterogeneous retroperitoneal mass and multiple hypodense hepatic lesions. Liver biopsy revealed leiomyosarcoma. In summary, although surgery is the mainstay of treatment, resectability has not improved significantly. Early recognition and aggressive surgery are keys to long-term survival.