Kyoto classification of gastritis: Advances and future perspectives in endoscopic diagnosis of gastritis

Iron deposition in gastric black spots: Clinicopathological insights and NanoSuit-correlative light and electron microscopy analysis

Objectives

Black spots (BSs) are lentiginous findings observed in the gastric body and fundus during upper gastrointestinal endoscopy and are predominantly seen in patients undergoing Helicobacter pylori eradication treatment. However, the detailed patient background and exact composition are poorly understood. This study aims to clarify the clinicopathological features of BSs, examine patient demographics, and use the NanoSuit-correlative light and electron microscopy (CLEM) method combined with scanning electron microscopy-energy dispersive X-ray spectroscopy for elemental analysis.

Methods

Patients who underwent upper gastrointestinal endoscopy between 2017 and 2022 were included. Data on age, medications, blood tests, and H. pylori infection status were retrospectively gathered from medical records. Univariate analysis was conducted to examine BS presence, with results then used in a multivariate model to identify associated risk factors. Additionally, pathological specimens from patients with BSs were analyzed for elemental composition using the NanoSuit-CLEM method combined with scanning electronmicroscopy-energy dispersive X-ray spectroscopy.

Results

An analysis of 6778 cases identified risk factors for BSs, including older age and using proton pump inhibitors, statins, corticosteroids, and antithrombotic drugs. Endoscopically, BSs correlated with higher gastric atrophy and lower active H. pylori infection. Iron deposition at BS sites was specifically identified using NanoSuit-CLEM.

Conclusions

BSs on gastrointestinal endoscopy may indicate an absence of active H. pylori inflammation. The discovery of iron deposition within BSs using the NanoSuit-CLEM method has offered new insights into the possible causative factors and advances our understanding of the etiology of BSs, bringing us closer to unraveling the underlying mechanisms of their formation.

A deep learning approach for gastroscopic manifestation recognition based on Kyoto Gastritis Score

OBJECTIVE

The risk of gastric cancer can be predicted by gastroscopic manifestation recognition and the Kyoto Gastritis Score. This study aims to validate the applicability of AI approaches for recognizing gastroscopic manifestations according to the definition of Kyoto Gastritis Score, with the goal of improving early gastric cancer detection and reducing gastric cancer mortality.

METHODS

In this retrospective study, 29013 gastric endoscopy images were collected and carefully annotated into five categories according to the Kyoto Gastritis Score, i.e. atrophy (A), diffuse redness (DR), enlarged folds (H), intestinal metaplasia (IM), and nodularity (N). As a multi-label recognition task, we propose a deep learning approach composed of five GAM-EfficientNet models, each performing a multiple classification to quantify gastroscopic manifestations, i.e. no presentation or the severity score 0-2. This approach was compared with endoscopists of varying years of experience in terms of accuracy, specificity, precision, recall, and F1 score.

RESULTS

The approach demonstrated good performance in identifying the five manifestations of the Kyoto Gastritis Score, with an average accuracy, specificity, precision, recall, and F1 score of 78.70%, 91.92%, 80.23%, 78.70%, and 0.78, respectively. The average performance of five experienced endoscopists was 72.63%, 90.00%, 77.68%, 72.63%, and 0.73, while that of five less experienced endoscopists was 66.60%, 87.44%, 70.88%, 66.60%, and 0.66, respectively. The sample t-test indicates that the approach's average accuracy, specificity, precision, recall, and F1 score for identifying the five manifestations were significantly higher than those of less experienced endoscopists, experienced endoscopists, and all endoscopists on average (p < 0.05).

CONCLUSION

Our study demonstrates the potential of deep learning approaches on gastric manifestation recognition over junior, even senior endoscopists. Thus, the deep learning approach holds potential as an auxiliary tool, although prospective validation is still needed to assess its clinical applicability.

The endoscopic model for gastric carcinogenesis and Helicobacter pylori infection: A potential visual mind-map during gastroscopy examination

Helicobacter pylori (Hp) is the main trigger of chronic gastric atrophy and the main leading cause of gastric cancer. Hp infects the normal gastric mucosa and can lead to chronic inflammation, glandular atrophy, intestinal metaplasia, dysplasia and finally adenocarcinoma. Chronic inflammation and gastric atrophy associated with Hp infection appear initially in the distal part of the stomach (the antrum) before progressing to the proximal part (the corpus-fundus). In recent years, endoscopic developments have allowed for the characterization of various gastric conditions including the normal mucosa (pyloric/fundic gland pattern and regular arrangement of collecting venules), Hp-related gastritis (Kyoto classification), glandular atrophy (Kimura-Takemoto classification), intestinal metaplasia (Endoscopic Grading of Gastric Intestinal Metaplasia), and dysplasia/adenocarcinoma (Vessel plus Surface classification). Despite being independent classifications, all these scales can be integrated into a single model: the endoscopic model for gastric carcinogenesis. This model would assist endoscopists in comprehending the process of gastric carcinogenesis and conducting a systematic examination during gastroscopy. Having this model in mind would enable endoscopists to promptly recognize the implications of Hp infection and the potential patient's risk of developing gastric cancer.

Characteristic endoscopic findings in Helicobacter pylori diagnosis in clinical practice

INTRODUCTION

Helicobacter pylori is a major risk factor for gastric cancer. In addition to eradication therapy, early-phase detection of gastric cancer through screening programs using high-vision endoscopy is also widely known to reduce mortality. Although European and US guidelines recommend evaluation of atrophy and intestinal metaplasia by high-vision endoscopy and pathological findings, the guideline used in Japan - the Kyoto classification of gastritis - is based on endoscopic evaluation, and recommends the grading of risk factors. This system requires classification into three endoscopic groups: H. pylori-negative, previous H. pylori infection (inactive gastritis), and current H. pylori infection (active gastritis). Major endoscopic findings in active gastritis are diffuse redness, enlarged folds, nodularity, mucosal swelling, and sticky mucus, while those in H pylori-related gastritis - irrespective of active or inactive status - are atrophy, intestinal metaplasia, and xanthoma.

AREAS COVERED

This review describes the endoscopic characteristics of current H. pylori infection, and how characteristic endoscopic findings should be evaluated.

EXPERT OPINION

Although the correct evaluation of endoscopic findings related to H. pylori remains necessary, if findings of possible infection are observed, it is important to diagnose infection by detection methods with high sensitivity and specificity, including the stool antigen test and urea breath test.

Clinical Characteristics of Patients With Previous Helicobacter pylori Infection-Induced Atrophic Gastritis

AIMS

Patients with atrophic gastritis unrelated to autoimmune gastritis (AIG) and without active Helicobacter pylori (H.pylori) infection or previous eradication therapy are considered to have previous Helicobacter pylori infection-induced atrophic gastritis (PHIG). This study aimed to clarify the clinical characteristics of patients with PHIG.

METHODS

Consecutive patients who underwent upper gastrointestinal endoscopy during the study period were enrolled in the study. Pepsinogen and gastrin levels, H. pylori serology, and endoscopic atrophic grade were assessed. Patients were divided into five groups based on their H. pylori status and disease history (PHIG, without H. pylori infection, with active H. pylori infection, with successful H. pylori eradication, and AIG). Their gastric cancer risk status was classified according to the ABC method of serological gastric cancer screening.

RESULTS

Of 536 consecutive patients who underwent upper gastrointestinal endoscopy during the study period, 318 were included (31 with PHIG, 77 without H. pylori infection, 101 with active H. pylori infection, 80 with successful H. pylori eradication, and 29 with AIG). Of the 31 patients with PHIG, 21 (68%) were H. pylori-seronegative, and 20 (65%) were classified as group A (normal pepsinogen, H. pylori-seronegative). Patients with PHIG accounted for 90.1% of the patients at high risk for gastric cancer misclassified as group A. The pepsinogen and H. pylori serological profiles of patients with PHIG were similar to those of patients with successful H. pylori eradication more than six years previously. A receiver-operating characteristic curve (ROC) analysis that included 13 patients with AIG and without active H. pylori infection and no previous eradication therapy and 31 patients with PHIG revealed that an endoscopic atrophy grade of O-III or greater according to the Kimura-Takemoto classification can predict AIG.

CONCLUSIONS

Two-thirds of the patients with PHIG were misclassified as being at low risk (group A) according to the ABC method, suggesting that endoscopy is necessary for group A patients. The results of the serological evaluation of PHIG indicated that patients with PHIG may have experienced spontaneous H. pylori eradication, possibly because of the use of antibiotics for other conditions. Autoimmune gastritis should be considered in the presence of grade 0-III or greater gastric mucosal atrophy in patients with suspected PHIG, even if the autoantibody and histological findings are not available.

Curative criteria for endoscopic treatment of gastric cancer

Endoscopic treatment, particularly endoscopic submucosal dissection, has become the primary treatment for early gastric cancer. A comprehensive optical assessment, including white light endoscopy, image-enhanced endoscopy, and magnification, are the cornerstones for clinical staging and determining the resectability of lesions. This paper discusses factors that influence the indication for endoscopic resection and the likelihood of achieving a curative resection. Our review stresses the critical need for interpreting the histopathological report in accordance with clinical guidelines and the imperative of tailoring decisions based on the patients' and lesions' characteristics and preferences. Moreover, we offer guidance on managing complex scenarios, such as those involving non-curative resection. Finally, we identify future research avenues, including the role of artificial intelligence in estimating the depth of invasion and the urgent need to refine predictive scores for lymph node metastasis and metachronous lesions.

Correlation analysis of endoscopic manifestations and eradication effect of Helicobacter pylori

Background

Helicobacter pylori (H. pylori) infection is the most important risk factor for gastric cancer. Eradication of H. pylori significantly reduces the incidence and mortality of gastric cancer. H. pylori resistance to antibiotics and a gradual decline in eradication rates are gaining more and more attention. Our study aimed to address the correlation between endoscopic manifestations and the eradication effect of H. pylori.

Methods

We retrospectively reviewed outpatients in our hospital with H. pylori infection undergoing eradication therapy from January 2022 to March 2023. Both the primary diagnosis and eradication of H. pylori after treatment were confirmed by a 13C urea breath test. Patients were treated with a proton pump inhibitor (PPI)-based quadruple therapy. Clinical characteristics and endoscopy manifestations within 7 days before or after patients were diagnosed with H. pylori infection were analyzed.

Results

From January 2022 to March 2023, a total of 323 patients were enrolled in this study. There were 138 male patients and 185 female patients. The mean age of patients was 45.62 ± 13.04 years. The H. pylori initial eradication rate was 82.0%. Univariate analysis of factors affecting H. pylori eradication showed that sex, age, and endoscopic manifestations including diffuse redness, multiple white, and flat elevated lesions, and atrophy were significantly associated with the failure of H. pylori eradication therapy. A multivariable logistic regression model analysis of these five factors showed that patients aged over 60 years with multiple white and flat elevated lesions in the endoscopic examination are significantly less likely to eradicate H. pylori with empirical quadruple therapy. On the other hand, patients with diffuse redness were significantly more likely to eradicate H. pylori infection with empirical quadruple therapy.

Conclusion

Our study shows that age over 60 years old, multiple white and flat elevated lesions in endoscopic examination are independent risk factors of initial H. pylori eradication failure with empirical quadruple therapy, while diffuse redness in endoscopic examination is a protective factor of initial H. pylori eradication failure with empirical quadruple therapy, while diffuse redness in endoscopic examination is a protective factor. For patients with these risk factors, a drug sensitivity test or H. pylori resistance gene mutation detection may be more appropriate. However, further mechanism studies or prospective studies are needed to prove our findings.

Gastric cancer incidence based on endoscopic Kyoto classification of gastritis

BACKGROUND

Gastric cancer (GC) incidence based on the endoscopic Kyoto classification of gastritis has not been systematically investigated using time-to-event analysis.

AIM

To examine GC incidence in an endoscopic surveillance cohort.

METHODS

This study was retrospectively conducted at the Toyoshima Endoscopy Clinic. Patients who underwent two or more esophagogastroduodenoscopies were enrolled. GC incidence was based on Kyoto classification scores, such as atrophy, intestinal metaplasia (IM), enlarged folds (EFs), nodularity, diffuse redness (DR), and total Kyoto scores. Hazard ratios (HRs) adjusted for age and sex were calculated using a Cox hazard model.

RESULTS

A total of 6718 patients were enrolled (median age 54.0 years; men 44.2%). During the follow-up period (max 5.02 years; median 2.56 years), GC developed in 34 patients. The average frequency of GCs per year was 0.19%. Kyoto atrophy scores 1 [HR with score 0 as reference: 3.66, 95% confidence interval (CI): 1.06 to 12.61], 2 (11.60, 3.82-35.27), IM score 2 (9.92, 4.37-22.54), EF score 1 (4.03, 1.63-9.96), DR scores 1 (6.22, 2.65-14.56), and 2 (10.01, 3.73-26.86) were associated with GC incidence, whereas nodularity scores were not. The total Kyoto scores of 4 (HR with total Kyoto scores 0-1 as reference: 6.23, 95%CI: 1.93 to 20.13, P = 0.002) and 5-8 (16.45, 6.29-43.03, P < 0.001) were more likely to develop GC, whereas the total Kyoto scores 2-3 were not. The HR of the total Kyoto score for developing GC per 1 rank was 1.75 (95%CI: 1.46 to 2.09, P < 0.001).

CONCLUSION

A high total Kyoto score (≥ 4) was associated with GC incidence. The endoscopy-based diagnosis of gastritis can stratify GC risk.