Atrophic Gastritis

Upper digestive tract cancers are often preceded by pre-malignant lesions, but there is limited evidence regarding optimal risk prediction models and screening strategies for disease progression and cancer development. This prospective multicenter cohort study aims to establish a longitudinal database integrating clinical information, endoscopic findings, pathology, genetics, epigenetics, and gastrointestinal microbiota data from subjects undergoing upper digestive tract endoscopy. The study will develop explainable artificial intelligence (AI)-based risk prediction models to identify factors associated with disease progression, treatment response, and cancer development. Participants will be followed longitudinally to evaluate changes in lesion severity and clinical outcomes.

Autoimmune atrophic gastritis (AAG) is an immune-mediated disorder characterized by the loss of oxyntic glands and mucosal atrophy1.Specific autoantibodies directed to gastric parietal cells (PCA) and/or to intrinsic factors are inconstantly present1.Despite its morbidity, data on the epidemiology are scant. Its global prevalence has been estimated to be 0.5-4.5%.Hypo-achlorhydria and lack of intrinsic factor lead to malabsorption of many nutrients, as vit. B12, iron and calcium.A damage on elevated turnover cells may develop, affecting hemopoiesis, nervous system, gut, and myocardium, depicting a systemic disease.Moreover, one of the primary function of gastric acidity as a bactericidal defensive barrier is impaired resulting in both gastric and intestinal microbiota modification. It was recently shown that conditions causing hypo-achlorhydria modify the composition of microbiota from stomach to colon. In particular, at colonic level a decrease in the abundance of commensal bacteria associated to a reduction in microbial diversity and an increase of oral bacteria in the stool were shown.The clinical spectrum is unspecific, especially in early stages, leading to substantial diagnostic delay.Patients may be asymptomatic or complain of gastrointestinal manifestations such as atrophic glossitis, malabsorption, diarrhea, and dyspepsia.These symptoms are insufficient for the diagnosis.Neurological and psychiatric symptoms are often overlooked; myocardial infarction due to demand imbalance may occur.Most of AAG manifestations and complications are due to cyanocobalamin deficiency that may be clinically silent for years.Vit. B12 deficiency has also been associated with infertility, very early recurrent miscarriage, failure of assisted reproductive technologies, and neural tube defects.Furthermore, AAG is a preneoplastic condition as may predispose to the development of type I carcinoids and gastric adenocarcinoma.A previous publication of our group on the NH of AAG,showed that all patients evolved into a higher degree of gastric atrophy and/or metaplasia; additionally,6.3%of these patients developed a neoplastic complication (median time of 3 yo).These data underlined the need to feel the gap of knowledge in the identification and characterization of the factors promoting neoplastic development or associated with carcinogenesis.Moreover, strategies for prevention and management of non-neoplastic complications and extra-gastrointestinal manifestation have to be better determined Hence, a larger, prospective study looking at this issue is warranted.

Gastric cancer afflicts 27,000 Americans annually and carries a dismal prognosis. One reason for poor outcomes is late diagnosis, as the majority of gastric cancers in the United States are diagnosed at a relatively advanced stage where curative resection is unlikely. Gastric precursors (such as atrophic gastritis and intestinal metaplasia) are precancerous changes to the stomach mucosa which increases risk for subsequent gastric cancer. The Gastric Precancerous Conditions Study (GAPS) is an observational study of patients at elevated risk for gastric cancer. Investigators seek to recruit patients from endoscopy unit of Stanford Health Care, a large academic network of hospitals and clinics serving Northern California. Investigators will recruit patients who are both symptomatic (e.g. dyspepsia) and asymptomatic (e.g. referred for screening), and individuals both with known precursor lesions (such as intestinal metaplasia) or at high risk for carrying precursor lesions. A component of the study is long-term follow-up of individuals with gastric precursors. This is to understand their risk factors for histologic progression and regression. During both index and subsequent endoscopies, the study team will collect biospecimens (e.g. blood, saliva, gastric tissue).

Currently no ideal preventive modalities are available for reducing gastric-cancer caused mortality in organized population-based application. The primary objective of the study is to determine if H.pylori screening followed by eradication of positive subjects and endoscopic follow-up of those with serological evidence of atrophic gastritis reduces mortality from gastric cancer in middle-aged people in high-risk areas. The GISTAR study is a multicenter randomized study of H.pylori eradication and pepsinogen testing for prevention of gastric cancer mortality. Altogether 30.000 individuals aged 40-64 years will be enrolled, providing 90% study power to detect at least 35% reduction in gastric cancer mortality at 15 years of follow-up. Participants will be randomly allocated to one of two groups. In the active investigation/management group those positive for H.pylori will be offered eradication therapy and individuals with decreased pepsinogen I/II ratio will be invited for endoscopy. The control group will receive standard health care. The primary endpoint for this trial will be the mortality difference from gastric cancer between the two groups at 15 years or when enough cases accumulate to demonstrate a statistical difference. The study is expected to provide valuable information on the utility for reduction in gastric cancer mortality of: 1) H.pylori eradication in adults on a population-basis, including subjects who may already have pre-malignant lesions; and 2) pepsinogen testing in screening settings. A pilot study of 3,455 individuals prior to the main trial was conducted from October 2013 to December 2016.

The aim of this observational study was to understand the effect of radiofrequency ablation on subjects with moderate to severe gastric atrophy with enterocolitis with or without low-grade intraepithelial neoplasia who underwent radiofrequency ablation. The main question it aims to answer is: Does radiofrequency ablation therapy reduce gastric mucosal atrophy and enterosis in subjects with moderate to severe gastric atrophy with enterosis with or without low-grade intraepithelial neoplasia?

Despite declining incidence rates, gastric cancer (GC) ranks the fourth leading cause of cancer-related mortality and the fifth most common cancer worldwide, with the highest incidence reported in Eastern Asia. The 5-year overall survival rate of early GC exceeds 90%, which was well above advanced GC. Most intestinal-type GCs follow the Correa cascade-inflammation,atrophy, intestinal metaplasia (IM), dysplasia and subsequent carcinoma. The presence of gastric mucosal atrophy and intestinal metaplasia are important risk factors for GC. The purpose of this study was to investigate the incidence of GC attributed to atrophic gastritis in a region with high incidence of GC.

Since much is unknown about factors that lead to progression of the pre-neoplastic lesions and cancer. In addition, there is ongoing debate on the optimal surveillance intervals and techniques. To solve these important clinical questions, the establishment of a registry for a longitudinal study is planned.

The primary objectives of this study are: * To identify clinical or histological factors associated with gastric cancer development in patients with IM and AG * To establish a machine learning algorithm for prediction of future gastric cancer risks and individual risk stratification in patient with IM and AG

Introduction: Gastric atrophy and intestinal metaplasia are the principal precursors for gastric cancer and, therefore, are considered gastric premalignant conditions. Although current guidelines recommend surveillance of individuals with these conditions, the best method for its identification and staging (histological vs endoscopy) and the best time schedule for follow-up are still controversial. Aims: To describe for the first-time patients with premalignant conditions both clinically (familial history), histologically (OLGA/OLGIM; complete/incomplete metaplasia) and endoscopically (EGGIM) using validated scales and to describe evolution of these parameters through time. To estimate prospectively the gastric cancer risk according to EGGIM stages. To define the best endoscopic surveillance follow-up for the several stages considering clinical, histological and endoscopic factors. Methods: Multicenter study involving different gastroenterology departments from several countries. Consecutive patients older than 45 years scheduled for upper endoscopy in each of these centers will be evaluated by High-Resolution- endoscopy with virtual chromoendoscopy and EGGIM will be calculated. Guided biopsies (if areas suspicious of IM) and/or random biopsies (if no areas suspicious of IM) in antrum and corpus will be made and OLGA/OLGIM stages calculated. Patients will be evaluated in clinical consultation and database will be fulfilled. All patients will be eradicated for Helicobacter pylori infection if positive. At that occasion, all the patients with EGGIM\>5 and/or OLGA III/IV and/or OLGIM III/IV will be randomized for yearly (12 to 16 months) or every three years (32-40 months) endoscopic follow-up during a period of 6 years (SUPREME I). Endoscopic observational follow-up will be scheduled for patients with EGGIM 1-4 and OLGIM I/II at 3 and 6 years (SUPREME II). For individuals with no evidence of IM (EGGIM 0 and OLGIM 0, OLGA 0-II) a follow-up endoscopy 6 years after will be proposed (SUPREME III).

The study is aimed to determine the potential of volatile marker testing for gastric cancer screening. The study will be addressing the role of confounding factors, including lifestyle factors, diet, smoking as well as addressing the potential role of microbiota in the composition of exhaled volatile markers.