Foregut: The Journal of the American Foregut Society

Graphical Abstract

This is a visual representation of the abstract.

Graphical Abstract

This is a visual representation of the abstract.

Chronic symptoms of gastric dysfunction are common following gastric surgery, but the mechanisms underlying these have remained poorly understood. Disturbances of foregut motility are suspected to play a central role, however knowledge of how these abnormalities manifest and relate to symptoms requires elucidation. Emerging data suggests that abnormalities of the gastric conduction system are a common consequence of gastric surgery and may contribute to dysmotility and post-operative symptoms. This review provides a primer on the gastric conduction system. The normal physiology of the gastric conduction system and factors that influence resilience to surgery are outlined, together with focused discussion on three surgical procedures that impact post-operative gastric dysfunction: resection of the gastric pacemaker, resection or bypass of the pylorus, and vagotomy. The mechanistic pathways that underpin the clinical effects of these procedures are discussed. Future horizons are also evaluated, including newly established body surface gastric mapping techniques that provide a non-invasive method to detect changes in the gastric conduction system and relate these to symptoms in postoperative patients, with the goal of developing targeted interventions for prevention and therapy.

For advanced carcinomas of the esophagus multimodal therapies consisting of neoadjuvant treatment with chemo- and/or radiation followed by surgical resection are the standard of care in western countries. Still unknown remains the question if clinical full responders to neoadjuvant treatment should receive an esophagectomy with all its perioperative risks as they could be pathological full responders potentially without further oncologic benefit. In this article we discuss the possible benefits and disadvantages of an organ sparing approach in comparison of the standard of care for patients with esophageal cancer.

Barrett’s esophagus (BE) refers to the mucosal transition from normal squamous mucosa to a genetically unstable specialized columnar-type intestinal metaplasia in the esophagus. Recent sophisticated studies using orthogonal techniques of molecular and computational biology strongly support that BE is the predominant pathway to esophageal adenocarcinoma (EAC). In this treatise, we review the risk of BE transforming to EAC and the latest developments in risk assessment of BE progression to EAC. The progression rate of BE to EAC can vary from one study to another depending on the region of origin, definition of BE, and variations in data capture. Overall, the published studies suggest that the risk of BE transforming to EAC is less than 0.5% per year and that to high-grade dysplasia (HGD) or EAC is less than 1% per year. Clinical tools to predict risk such as the Progression in Barrett’s (PIB) have been developed but will need further validation. p53 is the biomarker for risk stratification and has stood the test of time but is still not being widely used due to incomplete correlation between the mutational status and protein expression. Molecular studies using genomics and proteomics approaches are being evaluated but need to demonstrate good clinical accuracy before being translated into practice.

Barrett’s esophagus (BE) surveillance remains fraught with controversy and variation in real-world clinical practices. The application of current guideline-recommended surveillance intervals has not significantly impacted the incidence of esophageal adenocarcinoma (EAC), nor survival. One fifth of patients with EAC present in the first year after a negative upper endoscopy. Additionally, the progression from BE to EAC may occur in a non-linear fashion and more rapidly than previously believed due sudden genomic catastrophes requiring intensified surveillance. Emerging data supports the role of molecular markers for risk stratification and a more patient-centered surveillance approach rather than less vigorous universal surveillance intervals.

Gastric cancer remains one of the most common cancers globally. The pathogenesis of intestinal-type gastric cancer involves pre-malignant stages, including gastric intestinal metaplasia (GIM), the replacement of native gastric foveolar and/or glandular epithelium by intestinal-type epithelium. GIM prevalence is highly variable based on geography and race/ethnicity partly due to the varying prevalence of H. pylori, a potent risk factor. However, gastric cancer incidence does not mirror that of H. pylori, demonstrating a complex interaction between H. pylori and risk factors. We will discuss the epidemiology of GIM and gastric cancer, including incidence trends, risk factors, and implications for future management.

Patients undergoing foregut surgeries can have de novo findings or worsening of underlying upper gastrointestinal pathologies including Barrett’s esophagus and gastric intestinal metaplasia. These changes carry a potentially increased risk for malignancy development in the future raising the question of the utility of post-operative surveillance endoscopy after esophagectomy, bariatric and metabolic surgeries (Sleeve gastrectomy and Roux-en-Y Gastric Bypass), achalasia treatment, and anti-reflux surgery. In this narrative review, we conduct a literature exploration of available data on post-operative endoscopic surveillance findings following the procedures summarizing the prevalence of upper gastrointestinal pathologies and recommendations on the utility of postoperative endoscopy from established medical societies.

Esophageal adenocarcinoma (EAC) is rising in incidence and has a poor 5-year survival. Decades of targeted screening for Barrett’s esophagus (BE), the precursor to EAC, have not appreciably reduced EAC incidence. Here, we review the drawbacks of the current screening paradigm, including overreliance on GERD symptoms and sedated upper endoscopy. We debate the merits of a universal BE screening program. We propose an ideal BE screening strategy combining novel risk stratification models and non-invasive screening techniques to expand selective screening to patients without GERD, but at elevated risk for BE.

Specialized intestinal metaplasia is frequently found on biopsies from the squamo-columnar junction. It has been a matter of debate for many years whether this finding and/or columnar lined esophagus (CLE) with a length of up to 1 cm has a clinical significance. Many national society guidelines don’t consider a CLE <1 cm as Barrett’s esophagus (BE) since according to the Prague classification the diagnosis of a BE is not reliable enough. In addition, the risk for malignant progression is highly dependent from the length of the Barrett’s segment. It has been shown that the risk for progression is extremely low in CLE <10 mm and therefore a recommendation for regular surveillance endoscopies wouldn’t be cost effective. As a result, most society guidelines recommend that the diagnosis of BE should only be made in CLE >1 cm and when specialized intestinal metaplasia with goblet cells is confirmed on histopathology.

Artificial Intelligence (AI) has been increasingly applied in medical imaging for improved accuracy and efficiency. One area that has seen significant advances is the use of AI in the detection of Barrett’s esophagus (BE) and gastric intestinal metaplasia (GIM). BE is a pre-cancerous condition that occurs in the esophagus and can lead to esophageal adenocarcinoma, while GIM is a precancerous lesion that occurs in the stomach. In this review article, we will provide an overview of current AI techniques used in the detection and diagnosis of BE and GIM, including computer-aided diagnosis (CAD) systems, deep learning algorithms, and image analysis techniques. The performance of AI in detecting these conditions will be evaluated and compared to traditional methods. The challenges and limitations of using AI in the diagnosis of BE and GIM will also be discussed. The article aims to provide a comprehensive understanding of the use of AI in BE and GIM detection and to guide future research in this field.

Barrett’s esophagus and gastric intestinal metaplasia are precancerous conditions in the upper gastrointestinal tract that are easily identifiable on endoscopy. Although most cases will never progress to cancer, these conditions warrant endoscopic surveillance to detect and treat dysplasia. The key to detecting precancerous lesions is to follow a systematic approach for a high-quality examination. Additional steps to optimize practice are to apply image enhanced endoscopy, spend adequate time inspecting, appreciate principles of optical diagnosis, recognize mucosal and vascular patterns consistent with intestinal metaplasia and dysplasia, and take targeted biopsies of abnormalities.

This pilot study aimed to assess oral microbiome diversity between patients with and without elevated salivary pepsin concentrations. Over 9 months, 85 enrolled subjects (73 symptomatic patients; 12 asymptomatic volunteers) provided salivary samples off acid suppression. Subjects with elevated pepsin (≥25 ng/mL) had significantly greater Shannon entropy diversity compared to subjects with normal pepsin (<25 ng/mL) on 16S rRNA sequencing (P = .015), indicating increased oral microbiome biodiversity in patients with elevated salivary pepsin. Repeated gastro-esophageal reflux events from the stomach to the oral cavity may contribute to this observed change in oral microbiome diversity with potential implications in symptom generation and/or therapy.