The severity of endoscopic gastric atrophy could help to predict Operative Link on Gastritis Assessment gastritis stage

An artificial intelligence system for chronic atrophic gastritis diagnosis and risk stratification under white light endoscopy

BACKGROUND AND AIMS

The diagnosis and stratification of gastric atrophy (GA) predict patients' gastric cancer progression risk and determine endoscopy surveillance interval. We aimed to construct an artificial intelligence (AI) system for GA endoscopic identification and risk stratification based on the Kimura-Takemoto classification.

METHODS

We constructed the system using two trained models and verified its performance. First, we retrospectively collected 869 images and 119 videos to compare its performance with that of endoscopists in identifying GA. Then, we included original image cases of 102 patients to validate the system for stratifying GA and comparing it with endoscopists with different experiences.

RESULTS

The sensitivity of model 1 was higher than that of endoscopists (92.72% vs. 76.85 %) at image level and also higher than that of experts (94.87% vs. 85.90 %) at video level. The system outperformed experts in stratifying GA (overall accuracy: 81.37 %, 73.04 %, p = 0.045). The accuracy of this system in classifying non-GA, mild GA, moderate GA, and severe GA was 80.00 %, 77.42 %, 83.33 %, and 85.71 %, comparable to that of experts and better than that of seniors and novices.

CONCLUSIONS

We established an expert-level system for GA endoscopic identification and risk stratification. It has great potential for endoscopic assessment and surveillance determinations.

Gastrointestinal Microbiota Changes in Patients With Gastric Precancerous Lesions

Background

Gastric microbiota may be involved in gastric cancer. The relationship between gastrointestinal microbes and the risk of gastric cancer is unclear. This study aimed to explore the gastric and intestinal bacteria associated with gastritis and gastric precancerous lesions. We conducted a case-control study by performing 16S rRNA gene analysis of gastric biopsies, juices, and stool samples from 148 cases with gastritis or gastric precancerous lesions from Anhui and neighboring provinces, China. And we validated our findings in public datasets.

Results

Analysis of microbial sequences revealed decreased bacterial alpha diversity in gastric bacteria during the progression of gastritis. Helicobacter pylori was the main contributor to the decreased microbial composition and diversity in the gastric mucosa and had little influence on the microbiota of gastric juice and feces. The gastric mucosal genera Gemella, Veillonella, Streptococcus, Actinobacillus, and Hemophilus had the higher degree of centrality across the progression of gastric precancerous lesions. And Acinetobacter may contribute to the occurrence of intraepithelial neoplasia. In addition, the microbial model of H. pylori-positive gastric biopsies and feces showed value in the prediction of gastric precancerous lesions.

Conclusions

This study identified associations between gastric precancerous lesions and gastric microbiota, as well as the changes in intestinal microbiota, and explored their values in the prediction of gastric precancerous lesions.

Serum pepsinogen levels in different regions of China and its influencing factors: a multicenter cross-sectional study

BACKGROUND

The aim of this study is to investigate the difference of serum pepsinogen (PG) baseline levels in different regions of China and its influencing factors.

METHODS

From October 2016 to October 2018, asymptomatic health checkup people who underwent nasal endoscopy in nine health management centers in different regions of China were collected. Lifestyle questionnaires were conducted, and serum PG and gastroscopy were performed. The differences in PG levels in baseline population (OLGA-0 grade) were studied according to geographical subregions of China. SPSS software was used for statistical analysis.

RESULTS

1922 patients were included in the final analysis. Compared with the non-atrophy (OLGA-0) group, PGR levels in atrophy group (OLGA-I to IV) were significantly decreased with the atrophy degree (p < 0.05). A total of 1590 baseline people (OLGA-0) were included in the study, including 254 from South China, 574 from East China, 210 from Southwest China, 332 from Northeast China, and 220 from Central/Northern China. There were significant differences in baseline PGI levels among the five regions (p < 0.05). The PGII levels were also different among the five regions, except for Central/Northern versus Southern China. PGR (PGI/PGII ratio) levels in Southern China were higher than other four regions. Further studies were conducted on the related factors that might affect the baseline PG level, which was affected by nationality, dietary habits, smoking, Helicobacter pylori infection and other related factors.

CONCLUSION

Influenced by many factors, the baseline PG levels are different in different regions of China. In the follow-up studies of PG cut-off value, different PG cut-off value based on region may be more effective in the screening of gastric cancer and precancerous lesions in China.

Endoscopic grading of gastric atrophy on risk assessment of gastric neoplasia: A systematic review and meta-analysis

BACKGROUND AND AIM

Endoscopic examination of gastric atrophy has been developed to determine the extent of atrophy by identifying the atrophic border of gastric mucosa, but its value in predicting the risk of developing gastric neoplasms is not quantified. Thus, this systematic review and meta-analysis aim to assess the incidence risk of gastric neoplasms on the basis of endoscopic grading of gastric atrophy.

METHODS

Two authors independently searched the electronic databases (PubMed, Embase, and the Cochrane Library) from inception through December 31, 2019, without language restriction. The effect size on study outcomes is calculated using random-effects model and presented as risk ratio (RR) with 95% confidence interval (CI). Heterogeneity, publication bias, and quality of included studies were also assessed.

RESULTS

Fourteen retrospective studies are identified to perform systematic review and meta-analysis, 11 were cohort studies, and three were cross-sectional research. The pooled RR for developing gastric neoplasms is 3.89 (95% CI 2.92-5.17) among general patients with severe endoscopic atrophy. For patients who underwent endoscopic resection for early gastric neoplasms, nearly two times increased risk of synchronous or metachronous neoplasms is pooled (RR = 1.96, 95% CI 1.39-2.75). In terms of the type of endoscopic atrophy, patients with open-type endoscopic atrophy have a higher risk of gastric cancer development (RR 8.02; 95% CI 2.39-26.88) than those with close type. [Correction added on 22 December 2020, after first online publication: '(RR = 7.27; 95% CI 1.64-32.33)' has been corrected to '(RR 8.02; 95% CI 2.39-26.88)'] CONCLUSIONS: Grading endoscopic atrophy according to the Kimura-Takemoto classification can assess the risk of gastric neoplasia development. Patients with severe or open-type endoscopic gastric atrophy at baseline should undergo rigorous surveillance to early detect premalignant lesions and cancer.

Clinical applicability of gastroscopy with narrow-band imaging for the diagnosis of Helicobacter pylori gastritis, precancerous gastric lesion, and neoplasia

Premalignant gastric lesions such as atrophic gastritis and intestinal metaplasia frequently occur in subjects with long-term Helicobacter pylori (H. pylori) infection. The regular arrangement of collecting venules (RAC) is seen in the normal gastric corpus, whereas mucosal swelling and redness without RAC are observed in H. pylori-infected mucosa. Despite successful H. pylori eradication, the presence of atrophic gastritis and/or gastric intestinal metaplasia (GIM) is a risk factor for gastric cancer. With the development of advanced imaging technologies, recent studies have reported the usefulness of narrow-band imaging (NBI) for endoscopic diagnosis of atrophic gastritis and GIM. Using NBI endoscopy with magnification (M-NBI), atrophic gastritis is presented as irregular coiled microvessels and loss of gastric pits. Typical M-NBI endoscopic findings of GIM are a light blue crest and a white opaque substance. Based on the microvascular patterns, fine network, core vascular, and unclear patterns are useful for predicting gastric dysplasia in polypoid lesions. For diagnosis of early gastric cancer (EGC), a systematic classification using M-NBI endoscopy has been proposed on the basis of the presence of a demarcation line and an irregular microvascular/microsurface pattern. Furthermore, M-NBI endoscopy has been found to be more accurate for determining the horizontal margin of EGC compared to conventional endoscopy. In this review, we present up-to-date results on the clinical usefulness of gastroscopy with NBI for the diagnosis of H. pylori gastritis, precancerous gastric lesion, and neoplasia.

Pepsinogen Serology and Gastritis OLGA Staging in Mucosal Atrophy Assessment: A Cross-Sectional Study Involving East China Endoscopy Population

The histological gastric stage (OLGA) plays an important role in evaluating gastric atrophy, a symptom which suggests a risk of gastric cancer (GC). However, gastroscopy is an invasive examination, which has limited application in populations undergoing physical examination. Serum pepsinogen (PG) and gastin-17 (G-17) levels are noninvasive indexes which are recommended when screening for GC. We aim to explore the correlation between PG/G-17 and OLGA stage, in order to provide reliable indexes for GC screening. The study included 453 asymptomatic individuals from East China undergoing physical examination, who then underwent endoscopy including collection of biopsy samples. Assays for serum PG, G-17, and Helicobacter pylori (Hp) were performed. Atrophy of gastric mucosa was graded according to OLGA for each individual. 453 participants, average age 52.46 ± 10.30 years, 253 male and 200 female, were included. In the asymptomatic physical examination population, serum PGI, PGII, and PGR levels decreased with increasing OLGA scores. PGI and PGR were inversely correlated with increasing OLGA stage in both Hp-positive and Hp-negative groups. The levels of serum PGI, PGII, and G-17 in the Hp-positive group were higher than those in the Hp-negative group; conversely, the PGR levels were lower. Furthermore, OLGA scores increased with age in the Hp-positive group. In conclusion, there is a significant correlation between OLGA stage and serum PG in populations from East China undergoing physical examination. Serum PG and G-17 combined with Hp test plays an important role in evaluating gastric atrophy.

Endoscopic Kyoto classification of Helicobacter pylori infection and gastric cancer risk diagnosis

Recent advances in endoscopic technology allow detailed observation of the gastric mucosa. Today, endoscopy is used in the diagnosis of gastritis to determine the presence/absence of Helicobacter pylori (H. pylori) infection and evaluate gastric cancer risk. In 2013, the Japan Gastroenterological Endoscopy Society advocated the Kyoto classification, a new grading system for endoscopic gastritis. The Kyoto classification organized endoscopic findings related to H. pylori infection. The Kyoto classification score is the sum of scores for five endoscopic findings (atrophy, intestinal metaplasia, enlarged folds, nodularity, and diffuse redness with or without regular arrangement of collecting venules) and ranges from 0 to 8. Atrophy, intestinal metaplasia, enlarged folds, and nodularity contribute to gastric cancer risk. Diffuse redness and regular arrangement of collecting venules are related to H. pylori infection status. In subjects without a history of H. pylori eradication, the infection rates in those with Kyoto scores of 0, 1, and ≥ 2 were 1.5%, 45%, and 82%, respectively. A Kyoto classification score of 0 indicates no H. pylori infection. A Kyoto classification score of 2 or more indicates H. pylori infection. Kyoto classification scores of patients with and without gastric cancer were 4.8 and 3.8, respectively. A Kyoto classification score of 4 or more might indicate gastric cancer risk.

Assessment of Endoscopic Gastric Atrophy according to the Kimura-Takemoto Classification and Its Potential Application in Daily Practice

The assessment of endoscopic gastric atrophy (EGA) according to the Kimura-Takemoto classification has been reported to correlate well with histological assessment. Although agreement among beginner endoscopists was less than that among experienced endoscopists, it has been shown that agreement level could markedly improve and remained stable after proper training. Several cohort studies have consistently shown that the severity of EGA at baseline is significantly associated with the presence of advanced precancerous gastric lesions and gastric cancer, as well as the development of gastric cancer in future. Patients with moderate-to-severe EGA still have high risk of gastric cancer even after successful Helicobacter pylori eradication and should be candidates for gastric cancer surveillance. The assessment of EGA, therefore, could be used as a preliminary tool to identify individuals at high risk for gastric cancer. In this paper, we review the agreement on mucosal atrophy assessment between the Kimura-Takemoto classification and histology as well as the potential application of this endoscopic classification to identify precancerous gastric lesions and gastric cancer in daily practice.

Identifying high-risk individuals for gastric cancer surveillance from western and eastern perspectives: Lessons to learn and possibility to develop an integrated approach for daily practice

Current evidence shows that individuals with gastric dysplasia, severe and extensive gastric atrophy, extensive gastric intestinal metaplasia and the incomplete subtype of intestinal metaplasia are at high risk for gastric cancer (GC) development. There are several approaches to identifying these subjects, including noninvasive methods, esophagogastroduodenoscopy and histology. The main approach in Western countries is histology-based while that in Eastern countries with a high prevalence of GC is endoscopy-based. Regarding asymptomatic individuals, the key issues in selecting applicable approaches are the ability to reduce GC mortality and the cost-effectiveness of the approach. At present, population-based screening programs have only been applied in a few Asian countries with a high risk of GC. Pre-endoscopic risk assessment based on demographic and clinical features, such as ethnicity, age, gender, smoking and Helicobacter pylori status, is helpful for identifying subjects with high pre-test probability for a possibly cost-effective approach, especially in intermediate- and low-risk countries. Regarding symptomatic patients with indications for esophagogastroduodenoscopy, the importance of opportunistic screening should be emphasized. The combination of endoscopic and histological approaches should always be considered as endoscopy provides a real-time assessment of the patient’s risk level. In addition, imaging enhanced endoscopy (IEE) has been shown to facilitate targeted biopsies resulting in better correlation between endoscopic and histological findings. Currently, the use of IEE is recommended for endoscopic examinations, and the Operative Link for Gastric Intestinal Metaplasia or Operative Link on Gastritis Assessment grading systems are recommended for histological examinations whenever available. However, resource limitations are an important barrier in many regions worldwide. Thus, for an approach to be applicable in real-life practice, it should be not only evidence-based but also resource-sensitive. In this review, we discuss the current understanding and approaches to identifying high-risk individuals from western and eastern perspectives, as well as the possibility of an integrated, resource-sensitive approach.

OLGA Gastritis Staging for the Prediction of Gastric Cancer Risk: A Long-term Follow-up Study of 7436 Patients

OBJECTIVES

Gastritis OLGA-staging ranks the risk for gastric cancer (GC) in progressive stages (0-IV). This long-term follow-up study quantifies the GC risk associated with each OLGA stage.

METHODS

Consecutive patients (7436) underwent esophagogastroscopy (T-0), with mapped gastric biopsies, OLGA staging, and H. pylori status assessment. Patients with neoplastic lesion (invasive or non-invasive) at the index endoscopy (and/or within 12 months) were excluded. All patients were followed-up (T-1) by combining different sources of clinical/pathological information (Regional Registries of: (i) esophagogastroduodenoscopies; (ii) pathology reports; (iii) cancer, (iv) mortality). The endpoint was histologically documented development of gastric epithelial neoplasia.

RESULTS

At T-0, the patients' distribution by OLGA stage was: Stage 0 = 80.8%; Stage I = 12.6%; Stage II = 4.3%; Stage III = 2.0%; Stage IV = 0.3%; H. pylori infection was detected in 25.9% of patients. At the end of the follow-up (mean/median = 6.3/6.6 years), 28 incident neoplasia were documented (overall prevalence = 0.60 per 10³/person-years; low-grade intraepithelial neoplasia = 17/28; high-grade intraepithelial neoplasia = 4/28; GC = 7/28). By OLGA stage at the enrollment, the rate of incident neoplasia was: Stage 0 = 1 case; rate/10³ person-years = 0.03; 95%CI: 0.004-0.19; Stage I = 2 cases; rate/10³ person-years = 0.34; 95%CI: 0.09-1.36; Stage II = 3 cases; rate/10³ person-years = 1.48; 95%CI: 0.48-4.58; Stage III = 17 cases; rate/10³ person-years = 19.1; 95%CI: 11.9-30.7; Stage IV = 5 cases; rate/10³ person-years = 41.2; 95%CI: 17.2-99.3. Multivariate analysis including gender, age, H. pylori status, and OLGA stage at enrollment only disclosed OLGA stage as predictor of neoplastic progression (OLGA stage III: HR = 712.4, 95%CI = 92.543-5484.5; OLGA stage IV: HR = 1450.7, 95%CI = 166.7-12626.0).

CONCLUSIONS

Among 7436 patients, OLGA stages at the enrollment correlated significantly with different risk for gastric neoplasia. Based on the obtained results, gastritis staging is a critical adjunct in endoscopy follow-up protocols aimed at GC secondary prevention.

Long-term outcome of group D patients with negative serum anti-Helicobacter pylori antibody and positive serum pepsinogen test in healthy Koreans

OBJECTIVE

The aim of this study was to assess the clinical characteristics and long-term outcomes of group D patients (negative H. pylori antibodies and positive pepsinogen level).

METHODS

Group D patients were divided into two groups, that is, the limited endoscopic atrophic gastritis (EAG) group with EAG confined to the antrum and angle (C1 and C2) and the advanced EAG group with gastric body-involved EAG (C3 to O3). We compared the progression of precursor lesions and the occurrence of gastric neoplasms between the two groups.

RESULTS

Among 107 group D patients, the advanced EAG group (n = 60) was elder and had a lower pepsinogen I level and a lower pepsinogen I to II ratio (PGI/II) than the limited EAG group (n = 47). Among the 52 patients who underwent a follow-up endoscopy, three gastric neoplasms were detected (one in the limited and two in the advanced EAG groups). During a median follow-up of 44 months, 10 (43.5%) patients in the limited and 13 (52.0%) in the advanced EAG groups showed EAG progression or newly occurred intestinal metaplasia. A family history of GC (odds ratio [OR] 44.974, 95% confidence interval [CI] 1.360-1487.087), a lower PGI/II (OR 0.247, 95% CI 0.085-0.717) and a longer follow-up duration (OR 1.832, 95% CI 1.200-2.796) increased the risk of progression.

CONCLUSION

A family history of GC and low baseline PGI/II were independently associated with an increased risk of progression of precursor lesions of GC.

The significance of OLGA and OLGIM staging systems in the risk assessment of gastric cancer: a systematic review and meta-analysis

BACKGROUND

Despite extensive research on the criteria for the assessment of gastric cancer risk using the Operative Link on Gastritis Assessment (OLGA) and Operative Link on Gastritis/Intestinal-Metaplasia Assessment (OLGIM) systems, no comprehensive overview or systematic summary on their use is currently available.

AIM

To perform a systematic review and meta-analysis to assess the efficacy of the OLGA and OLGIM staging systems in evaluating gastric cancer risk.

METHODS

We searched various databases, including PubMed, EMBASE, Medline, and Cochrane's library, for articles published before March 2017 on the association between OLGA/OLGIM stages and risk of gastric cancer. Statistical analysis was performed using RevMan 5.30 and Stata 14.0, with the odds ratio, risk ratio, and 95% confidence interval as the effect measures.

RESULTS

A meta-analysis of six case-control studies and two cohort studies, comprising 2700 subjects, was performed. The meta-analysis of prospective case-control studies demonstrated a significant association between the OLGA/OLGIM stages III/IV and gastric cancer. The Newcastle-Ottawa Scale (NOS) score reflected heterogeneity in the case-control studies on OLGA. Subgroup analysis of high-quality (NOS score ≥ 5) studies showed an association between OLGA stage III/IV and increased risk of gastric cancer; the association was also high in the remaining study with low NOS score. The association between higher stages of gastritis defined by OLGA and risk of gastric cancer was significant.

CONCLUSIONS

This correlation implies that close and frequent monitoring of such high-risk patients is necessary to facilitate timely diagnosis of gastric cancer.

Training Effect on the Inter-observer Agreement in Endoscopic Diagnosis and Grading of Atrophic Gastritis according to Level of Endoscopic Experience

BACKGROUND

Endoscopic diagnosis of atrophic gastritis can contribute to risk stratification and thereby tailored screening for gastric cancer. We aimed to evaluate the effect of training on inter-observer agreement in diagnosis and grading of endoscopic atrophic gastritis (EAG) according to the level of endoscopists' experience.

METHODS

Twelve endoscopists (six less-experienced and six experienced) participated in this prospective study. The training session consisted of 1) four interventions with two-week intervals, and 2) a follow-up period (two follow-up assessments without feedback). EAG was categorized as C1 to O3 according to the Kimura-Takemoto classification. Kappa statistics were used to calculate inter-observer agreement.

RESULTS

At baseline, kappa indexes were 0.18 in the less-experienced group and 0.32 in the experienced group, respectively. After four interventions with feedback, the kappa index improved in both groups and was sustained during the follow-up period. Overall diagnostic yields of EAG were 43.1% ± 10.7% in pre-intervention and 46.8% ± 5.9% in post-intervention. Variability in the rate of diagnosis of EAG significantly decreased in the less-experienced group (r = 0.04, P = 0.003).

CONCLUSION

Irrespective of experience level, inter-observer agreement for diagnosis and grading of EAG improved after training and remained stable after intervention.

Association between gastric cancer and the Kyoto classification of gastritis

BACKGROUND AND AIM

Histological gastritis is associated with gastric cancer, but its diagnosis requires biopsy. Many classifications of endoscopic gastritis are available, but not all are useful for risk stratification of gastric cancer. The Kyoto Classification of Gastritis was proposed at the 85th Congress of the Japan Gastroenterological Endoscopy Society. This cross-sectional study evaluated the usefulness of the Kyoto Classification of Gastritis for risk stratification of gastric cancer.

METHODS

From August 2013 to September 2014, esophagogastroduodenoscopy was performed and the gastric findings evaluated according to the Kyoto Classification of Gastritis in a total of 4062 patients. The following five endoscopic findings were selected based on previous reports: atrophy, intestinal metaplasia, enlarged folds, nodularity, and diffuse redness.

RESULTS

A total of 3392 patients (1746 [51%] men and 1646 [49%] women) were analyzed. Among them, 107 gastric cancers were diagnosed. Atrophy was found in 2585 (78%) and intestinal metaplasia in 924 (27%). Enlarged folds, nodularity, and diffuse redness were found in 197 (5.8%), 22 (0.6%), and 573 (17%), respectively. In univariate analyses, the severity of atrophy, intestinal metaplasia, diffuse redness, age, and male sex were associated with gastric cancer. In a multivariate analysis, atrophy and male sex were found to be independent risk factors. Younger age and severe atrophy were determined to be associated with diffuse-type gastric cancer.

CONCLUSION

Endoscopic detection of atrophy was associated with the risk of gastric cancer. Thus, patients with severe atrophy should be examined carefully and may require intensive follow-up.

The potential value of serum pepsinogen for the diagnosis of atrophic gastritis among the health check-up populations in China: a diagnostic clinical research

BACKGROUND

The aim of this study is to assess the validity of the measurement of pepsinogen as a screening test for chronic atrophic gastritis (AG) in health check-up populations in China.

METHODS

Patients from consecutive regular health check-up were enrolled from January 2014 to June 2015. Endoscopy, combined with monitoring the Helicobacter pylori (Hp) infections, and measuring the serum pepsinogen (PG) were used to determine the diagnostic accuracy of PG for the screening of atrophic gastritis. Histopathology was assessed by the Operative Link on Gastritis Assessment (OLGA) system. Statistical analysis was performed using SPSS statistical software.

RESULTS

The total Hp infection rate was 40%. Based on pathology, the 996 participants were divided into three groups: non-atrophic (NAG), mild-moderate atrophic (MAG): stage I and II of the OLGA classification, and severe atrophic (SAG): stage III and IV of the OLGA classification. Compared with NAG and MAG groups, PGR decreased significantly in SAG group (p < 0.05). PGI and PGII levels were significantly elevated in Hp-positive group, while the PGR was markedly decreased (p < 0.01). When MAG and SAG groups were combined and compared with NAG group, the best cutoff value for atrophy diagnosis was PGI ≤50.3 ng/ml; the cutoff value in Hp-negative group was absolutely higher than in Hp-positive group. When NAG and MAG groups were combined and compared with the SAG group, the best cutoff value for diagnosis of severe atrophy was at PGR ≤4.28. The cutoff values in Hp-negative and Hp-positive groups were calculated at PGR ≤6.28 and ≤4.28, respectively.

CONCLUSIONS

Pepsinogens play an important role in the identification of patients with atrophic gastritis and severe AG. Use of different cutoff values of PG for Hp-negative and Hp-positive groups may offer greater efficacy in the diagnosis of AG.

Histologic intestinal metaplasia and endoscopic atrophy are predictors of gastric cancer development after Helicobacter pylori eradication

BACKGROUND AND AIMS

Helicobacter pylori eradication therapy is effective at reducing the incidence of gastric cancer; however, gastric cancer still develops after eradication. We conducted a cohort study to elucidate the risk factors for gastric cancer development after successful H pylori eradication therapy.

METHODS

From June 1998 to December 2012 we assessed histologic and endoscopic findings of gastritis and performed H pylori eradication therapy in 748 patients without a history of gastric cancer. Patients were classified according to the distribution of intestinal metaplasia (IM) as follows: no IM (IM group A), IM in the antrum only (IM group B), and IM in the corpus (IM group C). We assessed atrophy endoscopically according to the Kimura-Takemoto classification system. Gastric cancer incidence was assessed.

RESULTS

A total of 573 patients underwent follow-up endoscopy; the mean duration of follow-up was 6.2 ± 4.8 years. Gastric cancer developed in 21 (20 intestinal type). The cumulative 5-year incidences of gastric cancer were 3.2% overall; 1.5%, 5.3%, and 9.8% in IM groups A, B, and C; and 0.7%, 1.9%, and 10% in the none/mild, moderate, and severe endoscopic atrophy groups, respectively. Compared with IM group A, the hazard ratio for IM group B was 3.6 (95% confidence interval [CI], 1.2-11), and that for IM group C was 3.7 (95% CI, 1.1-12). Compared with the none/mild endoscopic atrophy group, the hazard ratio for severe atrophy was 9.3 (95% CI, 1.7-174).

CONCLUSIONS

Patients with histologic IM or severe endoscopic atrophy were at increased risk of gastric cancer development after H pylori eradication.

Operative link on gastritis assessment stage is an appropriate predictor of early gastric cancer

AIM

To assess the predictive value of Operative Link on Gastritis Assessment (OLGA) and Operative Link on Gastric Intestinal Metaplasia Assessment (OLGIM) stages in gastric cancer.

METHODS

A prospective study was conducted with 71 patients with early gastric cancer (EGC) and 156 patients with non-EGC. All patients underwent endoscopic examination and systematic biopsy. Outcome measures were assessed and compared, including the Japanese endoscopic gastric atrophy (EGA) classification method and the modified OLGA method as well as the modified OLGIM method. Helicobacter pylori (H. pylori) status was determined for all study participants. Stepwise logistic regression modeling was performed to analyze correlations between EGC and the EGA, OLGA and OLGIM methods.

RESULTS

For patients with EGC and patients with non-EGC, the proportions of moderate-to-severe EGA cases were 64.8% and 44.9%, respectively (P = 0.005), the proportions of OLGA stages III-IV cases were 52.1% and 22.4%, respectively (P < 0.001), and the proportions of OLGIM stages III-IV cases were 42.3% and 19.9%, respectively (P < 0.001). OLGA stage and OLGIM stage were significantly related to EGA classification; specifically, logistic regression modeling showed significant correlations between EGC and moderate-to-severe EGA (OR = 1.95, 95% CI: 1.06-3.58, P = 0.031) and OLGA stages III-IV (OR = 3.14, 95%CI: 1.71-5.81, P < 0.001), but no significant correlation between EGC and OLGIM stages III-IV (P = 0.781). H. pylori infection rate was significantly higher in patients with moderate-to-severe EGA (75.0% vs 54.1%, P = 0.001) or OLGA/OLGIM stages III-IV (OLGA: 83.6% vs 55.8%, P < 0.001; OLGIM: 83.6% vs 57.8%, P < 0.001).

CONCLUSION

OLGA classification is optimal for EGC screening. A surveillance program including OLGA stage and H. pylori infection status may facilitate early detection of gastric cancer.

Adenocarcinomas at different positions at the gastro-oesophageal junction show distinct association with gastritis and gastric preneoplastic conditions

OBJECTIVE

Adenocarcinomas at the gastro-oesophageal junction (GOJ) are currently stratified by tumour location. This retrospective study examines the association of preneoplastic conditions and inflammation of the gastric mucosa with GOJ cancer at different locations and compares them with nonjunctional gastric cancers.

PATIENTS AND METHODS

A total of 520 patients with junctional and nonjunctional gastric cancer were assessed for the presence and degree of intestinal metaplasia, glandular atrophy and inflammation in the stomach. Histopathological data were complete for 428 patients (68.9% men, median age 67.7 years), including 172 patients with GOJ cancer (GOJ1: 1-5 cm proximal to the junction, GOJ2: 'true' junctional, GOJ3: 2-5 cm distal to the junction). Gastric inflammation and preneoplastic conditions were scored according to the updated Sydney classification and further stratified into respective operative link on gastritis assessment (OLGA) and operative link on gastritis assessment on intestinal metaplasia (OLGIM) stages.

RESULTS

The prevalence and degree of gastric atrophy and intestinal metaplasia were significantly lower in GOJ1 than GOJ3 (P<0.01). Preneoplastic conditions in the stomach were similar in GOJ3 compared with nonjunctional gastric cancer. GOJ1 were almost exclusively (98.4%) of the intestinal type, whereas GOJ2 and GOJ3 were the diffuse type in 22.6 and 22.4% of the patients (P<0.001). Of all patients, only 8.5 and 12.7% presented with stage III/IV according to OLGA and OLGIM, respectively. However, data for OLGA and OLGIM staging were only available in 61.2 and 67.9% of patients, respectively.

CONCLUSION

GOJ1 are less likely to be associated with gastric pathology compared with GOJ3 or nonjunctional gastric cancer. OLGA or OLGIM staging in patients with advanced gastro-oesophageal cancer seems to be of limited value.

Accumulation of somatic mutations in TP53 in gastric epithelium with Helicobacter pylori infection

BACKGROUND & AIMS

Helicobacter pylori infection is a risk factor for gastric cancer. To explore the genetic basis of gastric cancer that develops in inflamed gastric mucosa, we investigated genetic aberrations that latently accumulate in nontumorous gastric epithelium with H pylori infection.

METHODS

We performed whole-exome sequencing of gastric tumors, noncancerous tissues with gastritis, and peripheral lymphocytes from 5 patients. We performed additional deep-sequencing analyses of selected tumor-related genes using 34 gastritis mucosal samples from patients with or without gastric cancer. We also performed deep sequencing analyses of gastric mucosal tissues from mice that express transgenic human TP53 and constitutively express activation-induced cytidine deaminase (AICDA or AID) (human TP53 knock-in/AID-transgenic mice).

RESULTS

Whole-exome sequencing revealed that somatic mutations accumulated in various genes in inflamed gastric tissues. Additional deep-sequencing analyses of tissues from regions of gastritis confirmed nonsynonymous low-abundance mutations in TP53 in 15 cases (44.1%) and ARID1A in 5 cases (14.7%). The mutations that accumulated in gastric mucosal tissues with H pylori-induced gastritis, as well as gastric tumors, were predominantly C:G>T:A transitions in GpCpX motifs-a marker of cytidine deamination induced by AID. Constitutive expression of AID in the gastric mucosa of mice led to mutations in the human TP53, at amino acid coding positions identical to those detected in human gastric cancers.

CONCLUSIONS

Studies of gastric tumors and tissues from humans and mice indicate that somatic mutations accumulate in various genes in gastric mucosal tissues with H pylori infection. Increased cytidine deaminase activity in these tissues appears to promote the accumulation of these mutations and might promote gastric carcinogenesis in patients with H pylori infection.

OLGA and OLGIM stage distribution according to age and Helicobacter pylori status in the Korean population

BACKGROUND

The Operative Link for Gastritis Assessment (OLGA) and the Operative Link on Gastric Intestinal Metaplasia Assessment (OLGIM) staging systems have been suggested to provide risk assessment for gastric cancer. This study aimed to evaluate the distribution of OLGA and OLGIM staging by age and Helicobacter pylori status.

MATERIALS AND METHODS

We studied 632 subjects who underwent esophagogastroduodenoscopy for gastric cancer screening. Helicobacter pylori status and histologic changes were assessed using the updated Sydney system. Stage III and IV OLGA or OLGIM stages were considered as high-risk stages.

RESULTS

The rate of H. pylori infection was 59.0% (373/632). Overall, the proportion of high OLGA and OLGIM stages was significantly increased with older age (p < .001 for both). Old age (OR = 5.17, 6.97, and 12.23 for ages in the 40's, 50's, and 60's, respectively), smoking (OR = 2.54), and H. pylori infection (OR = 8.46) were independent risk factors for high-risk OLGA stages. These risk factors were the same for high-risk OLGIM stages. In the H. pylori-positive subgroup, the proportion of high-risk OLGA stages was low (6.9%) before the age of 40, but increased to 23.0%, 29.1%, and 41.1% for those in their 40s, 50s, and 60s, respectively (p < .001). High-risk OLGIM stages showed a similar trend of 2.8% before the age of 40 and up to 30.1% for those in their 60s. High-risk OLGA and OLGIM stages were uncommon in the H. pylori-negative group, with a respective prevalence of 10.3% and 3.4% even among those in their 60s.

CONCLUSIONS

Because high-risk OLGA and OLGIM stages are uncommon under the age of 40, H. pylori treatment before that age may reduce the need for endoscopic surveillance for gastric cancer.

Prevalence of gastric precancerous conditions: a systematic review and meta-analysis

Several reports of estimates for precancerous conditions for gastric adenocarcinoma can be found in the current literature. Our aim was to systematically review and estimate the prevalence of gastric precancerous conditions. Four databases (PubMed, Scopus, Web of Knowledge and EBSCO Academic Search Complete) were searched for original manuscripts addressing the presence of chronic atrophic gastritis (CAG) or intestinal metaplasia (IM). Subgroup analysis was carried out on methods of diagnosis, type of population, incidence of gastric cancer, sex, Helicobacter pylori status, age and extent of conditions. Overall, 107 studies were included. The worldwide prevalence of CAG in the general population was 33% (95% confidence interval: 26-41%) when considering biopsies (n=20 912) and 24% (19-29%) if serology (n=51 886) was used, whereas IM was found in 25% (19-30%) (n=30 960). Estimates for CAG were higher in countries with a high incidence of gastric cancer (42 vs. 23%), men (32 vs. 28%), H. pylori positive (46 vs. 17%) and if aged 40 years or older (48 vs. 22%). The prevalence of extensive conditions was 16% (12-20%) for CAG and 13% (9.0-17%) for IM. When comparing countries with high versus low to moderate incidence of gastric cancer, significant differences were achieved for CAG: 27% (12-36%) versus 7.3% (5.6-9.0%). Worldwide, one-third and one-fourth of individuals may harbour CAG and IM, respectively. In countries with a high incidence of gastric cancer, the prevalence of extensive conditions may increase up to 27% and these patients represent a high-risk population to whom endoscopic surveillance should be offered according to recent guidelines.

Staging of intestinal- and diffuse-type gastric cancers with the OLGA and OLGIM staging systems

BACKGROUND

Operative link on gastritis assessment (OLGA) and Operative link on gastric intestinal metaplasia assessment (OLGIM) staging systems have been proposed for gastric cancer (GC) risk estimation.

AIM

To validate the OLGA and OLGIM staging systems in a region with high risk of GC.

METHODS

This retrospective study included 474 GC patients and age- and sex-matched health screening control persons in a cancer centre hospital. We classified gastritis patterns according to the OLGA and OLGIM systems using the histological database that a pathologist prospectively evaluated using the updated Sydney system. GC risk according to the OLGA and OLGIM stages was evaluated using logistic regression analysis.

RESULTS

More GC patients had OLGA stages III-IV (46.2%) than controls (26.6%, P < 0.001), particularly among patients with intestinal-type GCs (62.2%) compared with diffuse-type GCs (30.9%). OLGA stages III and IV were significantly associated with increased risk of GC [odds ratios (ORs), 2.09; P = 0.008 and 2.04; P = 0.014 respectively] in multivariate analysis. The association was more significant for intestinal-type (ORs, 4.76; P = 0.001 and 4.19; P = 0.002 respectively), but not diffuse-type GC. OLGIM stages from I to IV were significantly associated with increased risk of both intestinal-type (ORs, 3.64, 5.15, 7.89 and 13.20 respectively) and diffuse-type GC (ORs, 1.84, 2.59, 5.08 and 6.32 respectively) with a significantly increasing trend.

CONCLUSION

As high OLGA and OLGIM stages are independent risk factors for gastric cancer, the staging systems may be useful for risk assessment in high-risk regions, especially for intestinal-type gastric cancer.

Relationship between endoscopic and histologic gastric atrophy and intestinal metaplasia

BACKGROUND

The severity of endoscopic gastric atrophy (EGA), high-stage Operative Link on Gastritis Assessment (OLGA) gastritis (i.e., stage III or IV), and extensive intestinal metaplasia (IM) with incomplete subtype have been separately reported as high-risk factors of gastric cancer (GC). The aim of this study was to evaluate the associations between these endoscopic and pathologic characteristics.

MATERIALS AND METHODS

A cross-sectional study was conducted on 280 patients with functional dyspepsia at the University Medical Center at Ho Chi Minh City, Vietnam. Biopsies were taken according to the updated Sydney System. EGA was assessed according to the Kimura-Takemoto classification, and gastritis stage was assessed according to the OLGA system.

RESULTS

All of patients with high-stage OLGA gastritis (i.e., stage III or IV) clustered in the subgroup of patients with moderate-to-severe EGA: 13/126 (10.3%) in patients with moderate-to-severe EGA versus 0/154 (0%) in patients with none-to-mild EGA (p < .001). Moderate-to-severe EGA was also significantly associated with extensive IM (p < .001, OR = 28.1 (CI 95% 6.4-173.3)) and incomplete IM subtype (p < .001, OR = 36.7 (CI 95% 5.1-742.1). Extensive IM was also associated with incomplete IM subtype (p = .01).

CONCLUSIONS

High-stage OLGA gastritis, extensive IM with incomplete subtype clustered in patients with moderate-to-severe EGA. Assessing the severity of EGA could potentially help to identify patients who should be taken systemic biopsy for evaluating GC risk.