Combination of Helicobacter pylori Antibody and Serum Pepsinogen as a Good Predictive Tool of Gastric Cancer Incidence: 20-Year Prospective Data From the Hisayama Study

Chilean consensus by expert panel using the Delphi technique for primary and secondary prevention of gastric cancer

INTRODUCTION

Gastric cancer (GC) is the first cause of cancer-related death in Chile and 6th in Latin America and the Caribbean (LAC). Helicobacter pylori (H. pylori) is the main gastric carcinogen, and its treatment reduces GC incidence and mortality. Esophageal-gastro-duodenoscopy (EGD) allows for the detection of premalignant conditions and early-stage GC. Mass screening programs for H. pylori infection and screening for premalignant conditions and early-stage GC are not currently implemented in LAC. The aim of this study is to establish recommendations for primary and secondary prevention of GC in asymptomatic standard-risk populations in Chile.

METHODS

Two on-line synchronous workshops and a seminar were conducted with Chilean experts. A Delphi panel consensus was conducted over 2 rounds to achieve>80% agreement on proposed primary and secondary prevention strategies for the population stratified by age groups.

RESULTS

10, 12, and 12 experts participated in two workshops and a seminar, respectively. In the Delphi panel, 25 out of 37 experts (77.14%) and 28 out of 52 experts (53.85%) responded. For the population aged 16-34, there was no consensus on non-invasive testing and treatment for H. pylori, and the use of EGD was excluded. For the 35-44 age group, non-invasive testing and treatment for H. pylori is recommended, followed by subsequent test-of-cure using non-invasive tests (stool antigen test or urea breath test). In the ≥45 age group, a combined strategy is recommended, involving H. pylori testing and treatment plus non-invasive biomarkers (H. pylori IgG serology and serum pepsinogens I and II); subsequently, a selected group of subjects will undergo EGD with gastric biopsies (Sydney Protocol), which will be used to stratify surveillance according to the classification Operative Link for Gastritis Assessment (OLGA); every 3 years for OLGA III-IV and every 5 years for OLGA I-II.

CONCLUSION

A "test-and-treat" strategy for H. pylori infection based on non-invasive studies (primary prevention) is proposed in the 35-44 age group, and a combined strategy (serology and EGD) is recommended for the ≥45 age group (primary and secondary prevention). These strategies are potentially applicable to other countries in LAC.

Risk Prediction Models for Gastric Cancer: A Scoping Review

Background

Gastric cancer is a significant contributor to the global cancer burden. Risk prediction models aim to estimate future risk based on current and past information, and can be utilized for risk stratification in population screening programs for gastric cancer. This review aims to explore the research design of existing models, as well as the methods, variables, and performance of model construction.

Methods

Six databases were searched through to November 4, 2023 to identify appropriate studies. PRISMA extension for scoping reviews and the Arksey and O'Malley framework were followed. Data sources included PubMed, Embase, Web of Science, CNKI, Wanfang, and VIP, focusing on gastric cancer risk prediction model studies.

Results

A total of 29 articles met the inclusion criteria, from which 28 original risk prediction models were identified that met the analysis criteria. The risk prediction model is screened, and the data extracted includes research characteristics, prediction variables selection, model construction methods and evaluation indicators. The area under the curve (AUC) of the models ranged from 0.560 to 0.989, while the C-statistics varied between 0.684 and 0.940. The number of predictor variables is mainly concentrated between 5 to 11. The top 5 most frequently included variables were age, helicobacter pylori (Hp), precancerous lesion, pepsinogen (PG), sex, and smoking. Age and Hp were the most consistently included variables.

Conclusion

This review enhances understanding of current gastric cancer risk prediction research and its future directions. The findings provide a strong scientific basis and technical support for developing more accurate gastric cancer risk models. We expect that these conclusions will point the way for future research and clinical practice in this area to assist in the early prevention and treatment of gastric cancer.

Genome-wide 5-hydroxymethylcytosines in circulating cell-free DNA as noninvasive diagnostic markers for gastric cancer

BACKGROUND

5-Hydroxymethylcytosine-enriched gene profiles and regions show tissue-specific and tumor specific. There is a potential value to explore cell-free DNA 5-hydroxymethylcytosine feature biomarkers for early gastric cancer detection.

METHODS

A matched case‒control study design with 50 gastric cancer patients and 50 controls was performed to sequence the different 5-hydroxymethylcytosine modification features of cell free DNA. Significantly differential 5-hydroxymethylcytosine modification genes were identified to construct a gastric cancer diagnostic model. Data set from GEO was used as an external testing set to test the robustness of the diagnostic model.

RESULTS

Accounting for more than 90% of 5-hydroxymethylcytosine peaks were distributed in the gene body in both the gastric cancer and control groups. The diagnostic model was developed based on five different 5-hydroxymethylcytosine modification genes, FBXL7, PDE3A, TPO, SNTG2 and STXBP5. The model could effectively distinguish gastric cancer patients from controls in the training (AUC = 0.95, sensitivity = 88.6%, specificity = 94.3%), validation (AUC = 0.87, sensitivity = 73.3%, specificity = 93.3%) and testing (AUC = 0.90, sensitivity = 81.9%, specificity = 90.2%) sets. The risk scores of the controls from the model were significantly lower than those of gastric cancer patients in both our own data (P < 0.001) and GEO external testing data (P < 0.001), and no significant difference between different TNM stage patients (P = 0.09 and 0.66). Furthermore, there was no significant difference between the healthy control and benign gastric disease patients in the testing set from GEO (P = 0.10).

CONCLUSIONS

The characteristics of 5-hydroxymethylcytosine in cell free DNA are specific to gastric cancer patients, and the diagnostic model constructed by five genes' 5-hydroxymethylcytosine features could effectively identify gastric cancer patients.

Chronic atrophic gastritis and risk of incident upper gastrointestinal cancers: a systematic review and meta-analysis

BACKGROUND

Previous literature has explored the relationship between chronic atrophic gastritis (CAG) and isolated cancers within the upper gastrointestinal cancers; However, an integrative synthesis across the totality of upper gastrointestinal cancers was conspicuously absent. The research objective was to assess the relationship between CAG and the risk of incident upper gastrointestinal cancers, specifically including gastric cancer, oesophageal cancer, and oesophagogastric junction cancer.

METHODS

Rigorous systematic searches were conducted across three major databases, namely PubMed, Embase and Web of Science, encompassing the timeline from database inception until August 10, 2023. We extracted the necessary odds ratio (OR) and their corresponding 95% confidence interval (CI) for subsequent meta-analysis. Statistical analyses were conducted using Stata 17.0 software.

RESULTS

This meta-analysis included a total of 23 articles encompassing 5858 patients diagnosed with upper gastrointestinal cancers. CAG resulted in a statistically significant 4.12-fold elevated risk of incident gastric cancer (OR = 4.12, 95% CI 3.20-5.30). Likewise, CAG was linked to a 2.08-fold increased risk of incident oesophageal cancer (OR = 2.08, 95%CI 1.60-2.72). Intriguingly, a specific correlation was found between CAG and the risk of incident oesophageal squamous cell carcinoma (OR = 2.29, 95%CI 1.77-2.95), while no significant association was detected for oesophageal adenocarcinoma (OR = 0.62, 95%CI 0.17-2.26). Moreover, CAG was correlated with a 2.77-fold heightened risk of oesophagogastric junction cancer (OR = 2.77, 95%CI 2.21-3.46). Notably, for the same type of upper gastrointestinal cancer, it was observed that diagnosing CAG through histological methods was linked to a 33-77% higher risk of developing cancer compared to diagnosing CAG through serological methods.

CONCLUSION

This meta-analysis indicated a two- to fourfold increased risk of gastric cancer, oesophageal cancer, and oesophagogastric junction cancer in patients with CAG. Importantly, for the same upper gastrointestinal cancer, the risk of incident cancer was higher when CAG was diagnosed histologically compared to serological diagnosis. Further rigorous study designs are required to explore the impact of CAG diagnosed through both diagnostic methods on the risk of upper gastrointestinal cancers.

A novel predictive formula for highly accurate discrimination between truly Helicobacter pylori-uninfected and currently infected/spontaneously eradicated individuals for gastric cancer screening

The ABC classification, which categorizes gastric cancer risk based on serum Helicobacter pylori (H pylori) antibody and pepsinogen levels, has a limitation of potentially misclassifying high-risk individuals as low risk. To overcome the problem, we previously developed a 4-parameter predictive formula (age, serum H pylori antibody, PGI, and PGII) using logistic regression analysis to accurately identify low-risk truly H pylori-uninfected status. Our predictive formula demonstrated superior sensitivity and specificity in distinguishing between low-risk truly uninfected individuals and high-risk currently/spontaneously eradicated status individuals, compared to the modified ABC classification based on latex immunoassay kits (traditional 3-parameter model). This study aimed to revalidate the diagnostic accuracy of the predictive formula in a new and different study population. We applied the predictive formula to the target population and compared the sensitivity and specificity with those of the traditional 3-parameter model. A total of 788 enrollees were analyzed: 703 were classified as truly uninfected, 45 as currently infected, and 40 as spontaneously eradicated according to the results of stool antigen testing and endoscopic findings. The sensitivities and specificities of the predictive formula and the traditional 3-parameter model were 89.5% and 87.1% versus 89.8% and 80.0%, respectively. The specificity of the predictive formula was superior in the 70 to 89 age range and H pylori antibody < 3 U/mL groups. The predictive formula had higher specificity than the traditional 3-parameter model. The results should contribute to efficient gastric cancer screening by predicting H pylori infection status.

The Most Recent Insights into the Roots of Gastric Cancer

Helicobacter pylori (H. pylori) is the most common bacterial infection worldwide, usually being acquired during childhood, and its persistence into adulthood represents one of the main contributors of gastric carcinogenesis. Based on these statements, it would be of great importance to know if the most early premalignant transformation occurs in children or later since, this would enable the development of effective anti-tumorigenesis strategies. The interplay between H. pylori virulence factors, the host's responses modified by this infection, and the gastric microecology are complex and eventually lead to the development of gastric cancer in susceptible individuals. Several biomarkers were identified as major contributors of this long-lasting process, such as pepsinogens, gastrin 17, lipid-, glucose- and iron-metabolism parameters, immunity players, aberrant bacterial DNA methylation, H. pylori virulence factors, and hallmarks of gastric dysbiosis. Several of these biomarkers were also identified in children with H. pylori infection, independently of the presence of premalignant lesions, which were also proven to be present in a subgroup of H. pylori-infected children, especially those carrying extremely virulent strains. Therefore, the most incipient premalignant gastric changes might indeed occur early during childhood, opening a promising research gate for further studies to delineate the border between infection and cancer.

Precision endoscopy in the era of climate change and sustainability

Global warming caused by increased greenhouse gas (GHG) emissions has a direct impact on human health. Gastrointestinal (GI) endoscopy contributes significantly to GHG emissions due to energy consumption, reprocessing of endoscopes and accessories, production of equipment, safe disposal of biohazardous waste, and travel by patients. Moreover, GHGs are also generated in histopathology through tissue processing and the production of biopsy specimen bottles. The reduction in unnecessary surveillance endoscopies and biopsies is a practical approach to decrease GHG emissions without affecting disease outcomes. This narrative review explores the role of precision medicine in GI endoscopy, such as image-enhanced endoscopy and artificial intelligence, with a focus on decreasing unnecessary endoscopic procedures and biopsies in the surveillance and diagnosis of premalignant lesions in the esophagus, stomach, and colon. This review offers strategies to minimize unnecessary endoscopic procedures and biopsies, decrease GHG emissions, and maintain high-quality patient care, thereby contributing to sustainable healthcare practices.

Prediction algorithm for gastric cancer in a general population: A validation study

BACKGROUND

Worldwide, gastric cancer is a leading cause of cancer incidence and mortality. This study aims to devise and validate a scoring system based on readily available clinical data to predict the risk of gastric cancer in a large Chinese population.

METHODS

We included a total of 6,209,697 subjects aged between 18 and 70 years who have received upper digestive endoscopy in Hong Kong from 1997 to 2018. A binary logistic regression model was constructed to examine the predictors of gastric cancer in a derivation cohort (n = 4,347,224), followed by model evaluation in a validation cohort (n = 1,862,473). The algorithm's discriminatory ability was evaluated as the area under the curve (AUC) of the mathematically constructed receiver operating characteristic (ROC) curve.

RESULTS

Age, male gender, history of Helicobacter pylori infection, use of proton pump inhibitors, non-use of aspirin, non-steroidal anti-inflammatory drugs (NSAIDs), and statins were significantly associated with gastric cancer. A scoring of ≤8 was designated as "average risk (AR)". Scores at 9 or above were assigned as "high risk (HR)". The prevalence of gastric cancer was 1.81% and 0.096%, respectively, for the HR and LR groups. The AUC for the risk score in the validation cohort was 0.834, implying an excellent fit of the model.

CONCLUSIONS

This study has validated a simple, accurate, and easy-to-use scoring algorithm which has a high discriminatory capability to predict gastric cancer. The score could be adopted to risk stratify subjects suspected as having gastric cancer, thus allowing prioritized upper digestive tract investigation.

Performing the ABC Method Twice for Gastric Cancer Risk Stratification: A Retrospective Study Based on Data from a Large-Scale Screening Facility

The ABC method is a classification method used for stratifying the risk of gastric cancer. However, whether the ABC method should be performed only once or multiple times throughout an individual’s lifetime remains unclear. Therefore, this study aimed to analyze whether performing ABC screening twice in a lifetime is useful. We retrospectively analyzed the data of individuals who participated in health checkups in 2010 and 2015. We collected data on patient characteristics, pepsinogen levels, anti-Helicobacter pylori antibody titers, and the presence of gastric cancer. Overall, 7129 participants without a history of H. pylori eradication were included in this study. The participants’ average age in 2010 was 48.4 ± 8.3 years, and 58.1% were male. In addition, 11 and 20 cases of new H. pylori infection (0.15%) and spontaneous eradication (0.28%), respectively, were recorded. No significant difference was found in the incidence of gastric cancer between participants who underwent the ABC method once and those who underwent it twice (Group A: 0.16% vs. 0.16%; Group B: 0.47% vs. 0.39%; and Group C + D: 1.97% vs. 1.82%). Therefore, performing the ABC method twice, 5 years apart, does not significantly improve gastric cancer risk stratification.

Development of a modified ABC method among Helicobacter pylori infected but serum pepsinogen test-negative individuals

BACKGROUND

Although the ABC method for gastric cancer (GC) screening has been widely adopted in Japan, it may not be suitable for other countries due to population heterogeneity and different tumor histology. We aim to develop a modified ABC method to improve GC screening performance, especially among Helicobacter pylori (Hp) infected but serum pepsinogen (sPG) test-negative individuals.

METHODS

A total of 4745 participants were recruited from Tianjin, China, and were classified into four groups by combined assay for Hp infection and sPG concentrations: Group A (Hp [-], PG [-]), Group B (Hp [+], PG [-]), Group C (Hp [+], PG [+]), and Group D (Hp [-], PG [+]). We used receiver-operating characteristic (ROC) curves analysis and minimum p value method to determine the optimal cutoff point for PG II in Group B. We performed logistic regressions to examine the risk of GC across different subgroups. In addition to the derivation set, the performance of the modified ABC method was also evaluated in an external set involving 16,292 participants from Liaoning, China.

RESULTS

In the modified ABC method, we further classified Group B as low-risk (Group B1) and high-risk subgroups (Group B2) using optimal sPG II cutoff point (20.0 ng/mL) by ROC curves analysis and minimum p value method. Compared with Group B1, Group B2 had a significantly higher risk of GC (adjusted OR = 2.54, 95% CI = 1.94-3.33). The modified ABC method showed good discrimination for GC (AUC = 0.61, 95% CI = 0.59-0.63) and improved risk reclassification (NRI = 0.11, p < .01). Similar results were observed in the validation dataset.

CONCLUSIONS

The modified ABC method can effectively identify high-risk population for GC among Hp-infected but sPG test-negative participants in China.

Real-World Practice of Gastric Cancer Prevention and Screening Calls for Practical Prediction Models

INTRODUCTION

Some gastric cancer prediction models have been published. Still, the value of these models for application in real-world practice remains unclear. We aim to summarize and appraise modeling studies for gastric cancer risk prediction and identify potential barriers to real-world use.

METHODS

This systematic review included studies that developed or validated gastric cancer prediction models in the general population.

RESULTS

A total of 4,223 studies were screened. We included 18 development studies for diagnostic models, 10 for prognostic models, and 1 external validation study. Diagnostic models commonly included biomarkers, such as Helicobacter pylori infection indicator, pepsinogen, hormone, and microRNA. Age, sex, smoking, body mass index, and family history of gastric cancer were frequently used in prognostic models. Most of the models were not validated. Only 25% of models evaluated the calibration. All studies had a high risk of bias, but over half had acceptable applicability. Besides, most studies failed to clearly report the application scenarios of prediction models.

DISCUSSION

Most gastric cancer prediction models showed common shortcomings in methods, validation, and reports. Model developers should further minimize the risk of bias, improve models' applicability, and report targeting application scenarios to promote real-world use.

H. pylori-associated chronic gastritis: status update on the problem

Chronic gastritis is a group of chronic diseases that are morphologically characterized by persistent inflammatory infiltrate and impaired cellular turnover with the development of intestinal metaplasia, atrophy, and epithelial dysplasia in the gastric mucosa. Numerous studies have shown that Helicobacter pylori (H. pylori) infection is the absolutely dominant etiological factor of CG worldwide. Given this fact, the Expert Council of the latest Maastricht VI 2022 consensus recommended that H. pylori is to be treated as a pathogen, which always results in the development of CG. The prevalence of H. pylori-associated CG is about 44.3–48.5%, however 80–90% of cases are asymptomatic. In H. pylori­infected patients with dyspepsia and no other pathology of the gastroduodenal region, which has been confirmed endoscopically, clinical manifestations can be interpreted as part of H. pylori­associated CG if a long-lasting remission of symptoms has been achieved after successful eradication therapy. While patients with persistent dyspeptic symptoms can be considered as patients with functional dyspepsia, despite successful eradication therapy. Advanced endoscopic techniques (narrow band imaging (NBI) endoscopy, high resolution endoscopy, chromoendoscopy, laser confocal endomicroscopy) are precise and reproducible methods for diagnosing precancerous changes in the mucous membrane. However, the diagnosis of CG requires that inflammatory cells have been histologically detected in the lamina propria. The CG therapy aims to reach a persistent relief of dyspeptic symptoms of the disease (if any), as well as resolution of inflammatory processes and prevention of the progression of precancerous changes in the gastric mucosa. The achievement of these goals is primarily determined by the timely diagnosis of H. pylori infection and successful eradication therapy.

Identification of Helicobacter pylori-related gastric cancer risk using serological gastritis markers and endoscopic findings: a large-scale retrospective cohort study

Background

Gastric cancer remains a severe public health problem worldwide, particularly in Japan. Recent studies have demonstrated that serum markers are beneficial for risk stratification in gastric cancer development. We aimed to evaluate the usefulness of serum markers either alone or in combination (serum markers plus endoscopy) for effective risk stratification of gastric cancer development.

Methods

We enrolled 22,736 patients aged 20–95 years who underwent blood sampling and endoscopic examination at Hiroshima University Hospital in Japan between 1990 and 2014. The serum pepsinogen (PG) levels and anti-Helicobacter pylori antibody (Hp-Ab) titers were evaluated in each patient. The enrolled patients were matched with the database of the Hiroshima Prefecture Regional Cancer Registry. We processed the medical records and excluded patients with possible confounding factors for PG levels, such as proton pump inhibitor use, prior successful eradication therapy, post-gastrectomy, severe hepatorenal dysfunction, Zollinger–Ellison syndrome, and autoimmune gastritis. Among the remaining 5131 patients, we reviewed records of endoscopic examinations and selected 1507 patients (mean age, 62.5 years; 985 men and 522 women) who underwent endoscopic examination more than three months after blood sampling.

First, based on the ABC method, patients were classified as follows: High PG levels and negative Hp-Ab, group A, high PG levels and positive Hp-Ab, group B, low PG levels and positive Hp-Ab, group C, and low PG levels and negative Hp-Ab, group D. Group A was further classified into two subgroups using endoscopic findings: true A without atrophic gastritis and pseudo A with atrophic gastritis. All patients underwent annual endoscopy follow-up.

Results

Among the 1,507 patients (mean age, 62.5 years; 985 men), 24 were diagnosed with newly developed gastric cancer. No significant difference in cancer development was found between group A (PG negative and Hp-Ab negative) and the other groups. Remarkably, no true A group subjects developed gastric cancer.

Conclusions

The combination of serum markers and endoscopic findings is essential for the risk evaluation of gastric cancer.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-022-02381-z.

Risk factors for gastric cancer in Japan in the 2010s: a large, long-term observational study

BACKGROUND

The numbers of Helicobacter pylori (HP)-infected individuals and deaths due to gastric cancer are decreasing in Japan. We aimed to determine whether the serological test for chronic gastritis (the ABC method) is still useful for gastric cancer risk stratification in the 2010s and to analyze risk factors for developing gastric cancer in Japan.

METHODS

In this prospective study, we monitored 20773 individuals for the incidence of gastric cancer from 2010 to 2019. The relationships between blood sampling results, physical examination, and lifestyle in 2010 and the cumulative incidence of gastric cancer were analyzed.

RESULTS

A total of 19343 participants who met the study criteria were analyzed. Overall, 0.08% of participants in group A (9/11717), 0.63% in group B (28/4452), 2.05% in group C (43/2098), 1.52% in group D (1/66), and 0.30% in group E (3/1010) developed gastric cancer. Cox hazard analysis showed that age ≥ 50 years; groups B, C, and D according to the ABC method; and current smoking habits were independent risk factors for gastric cancer. The hazard ratios (HRs) of the incidence of gastric cancer were 6.7 in group B and 21.7 in groups C and D, while the HRs of group E was 2.8, which was not significantly different from that of group A. The incidence of gastric cancer was not statistically significantly different between those with and without successful HP eradication in groups B, C, and D during follow-up.

CONCLUSIONS

The ABC method was still useful for gastric cancer risk stratification in the 2010s.

Prediction models for gastric cancer risk in the general population: a systematic review

Risk prediction models for gastric cancer (GC) could identify high-risk individuals in the general population. The objective of this study was to systematically review the available evidence about the construction and verification of GC predictive models. We searched PubMed, Embase, and Cochrane Library databases for articles that developed or validated GC risk prediction models up to November 2021. Data extracted included study characteristics, predictor selection, missing data, and evaluation metrics. Risk of bias (ROB) was assessed using the Prediction model study Risk Of Bias Assessment Tool (PROBAST). We identified a total of 12 original risk prediction models that fulfilled the criteria for analysis. The area under the receiver operating characteristic curve ranged from 0.73 to 0.93 in derivation sets (n=6), 0.68 to 0.90 in internal validation sets (n=5), 0.71 to 0.92 in external validation sets (n=7). The higher-performing models usually include age, salt preference, Helicobacter pylori, smoking, BMI, family history, pepsinogen and sex. According to PROBAST, at least one domain with a high ROB was present in all studies mainly due to methodologic limitations in the analysis domain. In conclusion, although some risk prediction models including similar predictors have displayed sufficient discriminative abilities, many have a high ROB due to methodological limitations and are not externally validated efficiently. Future prediction models should adherence to well-established standards and guidelines to benefit GC screening.

The Optimal Cut-off of the Latex Immunoassay (LZ Test) for Helicobacter pylori Infection Based on the Stool Antigen Test and Helicobacter pylori-associated Gastritis

Objective Helicobacter pylori antibody kits using the latex immunoassay (LIA) are widely used in Japan. However, the optimal cut-off of the LIA remains unclear. This study clarified the optimal cut-off of the LIA for assessing the current infection status of patients (currently infected, never infected, spontaneously eradicated) in clinical practice. Methods In total, 482 subjects with no history of H. pylori eradication therapy who underwent a medical examination at our hospital were enrolled. The infection status was ascertained using a stool antigen test, and the endoscopic findings of H. pylori-associated gastritis. H. pylori antibody levels were measured using the LIA. Results In total, 414, 38, and 30 subjects were categorized into the never-infected, currently infected, and spontaneously eradicated groups. The optimal cut-off based on receiver operating characteristic curve analysis was 4 U/mL, whereas the area under the curve, sensitivity, and specificity for differentiating never-infected and currently infected subjects were 0.95, 92.1%, and 94.7%, respectively. When applying the cut-off of 4 U/mL to the judgment of current infection in all subjects, the sensitivity and specificity were 92.1% and 92.6%, respectively. Conclusion Our findings suggest that 4 U/mL was the optimal cut-off for differentiating current infection from no prior infection, and the value may be stable because of the exclusion of subjects with spontaneous eradication. The cut-off may be useful in initial screening for current H. pylori infection.

Machine learning: A non-invasive prediction method for gastric cancer based on a survey of lifestyle behaviors

Gastric cancer remains an enormous threat to human health. It is extremely significant to make a clear diagnosis and timely treatment of gastrointestinal tumors. The traditional diagnosis method (endoscope, surgery, and pathological tissue extraction) of gastric cancer is usually invasive, expensive, and time-consuming. The machine learning method is fast and low-cost, which breaks through the limitations of the traditional methods as we can apply the machine learning method to diagnose gastric cancer. This work aims to construct a cheap, non-invasive, rapid, and high-precision gastric cancer diagnostic model using personal behavioral lifestyles and non-invasive characteristics. A retrospective study was implemented on 3,630 participants. The developed models (extreme gradient boosting, decision tree, random forest, and logistic regression) were evaluated by cross-validation and the generalization ability in our test set. We found that the model developed using fingerprints based on the extreme gradient boosting (XGBoost) algorithm produced better results compared with the other models. The overall accuracy of which test set was 85.7%, AUC was 89.6%, sensitivity 78.7%, specificity 76.9%, and positive predictive values 73.8%, verifying that the proposed model has significant medical value and good application prospects.

Potential Non-invasive Biomarkers of Helicobacter pylori-Associated Gastric Cancer

BACKGROUND

Gastric cancer (GC) remains the fifth most common incident cancer with the highest incidence in East Asian countries and the third leading cause of cancer death worldwide. The causal association between non-cardia GC and Helicobacter pylori (H. pylori) has been firmly documented by clinical and epidemiological studies. According to the guidelines for diagnosis and treatment of H. pylori infection, eradication therapy is strongly recommended. Early detection of GC is critical and can save lives through rapid technological advancement. At present, endoscopy remains the most efficient technique. However, it is invasive and costs highly.

METHODS

An extensive bibliographic search was performed via PubMed/Medline, Web of Science, and EBSCO host databases to select studies conducted within the past 8 years. Forty-six relevant analyses were encompassed in this review.

RESULTS

Several non-invasive candidate biomarkers associated with H. pylori, divided into virulence markers, transcriptome markers, genomic markers, and inflammatory markers, have been shown to be potential predictors of GC at an early stage.

CONCLUSION

The discovery of non-invasive biomarkers offers new perspectives for screening, early detection, and monitoring of individuals at risk.

Clinical Value of Pepsinogen in the Screening, Prevention, and Diagnosis of Gastric Cancer

OBJECTIVES

To compare the levels of serum pepsinogen (PG) in patients with gastric cancer (GC), patients with atrophic gastritis (AG), and healthy donors. Also, we explored the clinical value of PG detection for the diagnosis and treatment of GC.

METHODS

The PG level in peripheral blood from patients and heathy donors was determined using an Abbott automatic chemiluminescence instrument. The study included 117 patients with GC confirmed by gastroscopy and histopathology, of whom 13 patients had cancer at stage I, 47 at stage II, 41 at stage III, and 16 at stage IV. The AG group included 122 patients, and the control group had 120 healthy donors. The relationship between serum PG levels and the occurrence and development of GC, as well as the evaluation of the clinical value of diagnostic tests based on serum PG detection, were investigated by receiver operating characteristic (ROC) curve analyses.

RESULTS

Pepsinogen I (PGI) levels gradually decreased from the control group, the AG group, and the GC group. PGI exhibited high diagnostic value for GC (area under the curve [AUC], 0.834; cutoff, 51.2 ng/mL, sensitivity, 81.7%; specificity, 68.4%), PGII (AUC, 0.587; cutoff value, 13.05 ng/mL; sensitivity, 65.8%; specificity, 53.8%), and PGR (AUC, 0.752; cutoff, 5.65; sensitivity, 54.2%; specificity, 87.2%). The occurrence of GC was negatively correlated with serum levels of PGI (B = -0.054; OR = 0.947; 95% confidence interval [CI], 0.925-0.970; P <.001) and PGR (B = -0.420; OR = 0.657; 95% CI, 0.499-0.864; P = .003).

CONCLUSIONS

The combined detection of PGI, PGII, and PGR has important clinical value for the screening, prevention, and diagnosis of GC and could allow for earlier detection, diagnosis, and treatment of GC.

Diagnostic Value of Serum Pepsinogen Levels for Screening Gastric Cancer and Atrophic Gastritis in Asymptomatic Individuals: A Cross-Sectional Study

Background

Pepsinogens (PGs) can be used for gastric cancer (GC) screening, but the cutoff levels vary among studies, and PG levels are influenced by numerous factors. The aim of this article is to examine the diagnostic value of PG levels and Helicobacter pylori (Hp) status for GC and atrophic gastritis screening in asymptomatic individuals undergoing health checkup in China.

Patients and Methods

This was a multicenter cross-sectional study of subjects who underwent health checkup from 10/2016 to 10/2018 at nine International Healthcare Centers in China. All participants underwent gastroscopy and pathological examination, serum PG, ¹³C-urea breath test, and/or Hp serological current infection marker rapid test, all on the same day. PG-related parameters were analyzed in different Hp subgroups and regions.

Results

The patients were grouped as non-atrophic (NAG, n = 1,590), mild to moderate atrophic (MAG, n = 273), severe atrophic (SAG, n = 49), and GC (n = 10). The serum PG levels in these groups decreased with increasing pathological severity. In the same pathological groups, PGI and PGII levels were higher in the Hp-positive subgroup, while PGR (PGI/PGII ratio) was lower (P < 0.05). The best cutoff values for atrophy diagnosis were PGI ≤73.1 ng/ml and PGR ≤9.8, for severe atrophy were PGI ≤63.9 ng/ml and PGR ≤9.09, and for GC was PGR ≤4.7 (all P < 0.05 and area under the curve >0.7). The cutoff points varied with Hp status and China regions.

Conclusion

Serum PG levels might be used for the screening of gastric atrophic gastritis lesions. The results suggest that different cutoff values should possibly be used in different Hp status groups and geographical regions, but it will have to be validated in future studies. Future studies should also examine the value of PG levels for GC detection.

Serum Helicobacter pylori antibody reactivity in seven Asian countries using an automated latex aggregation turbidity assay

BACKGROUND AND AIM

To determine the application range of diagnostic kits utilizing anti-Helicobacter pylori antibody, we tested a newly developed latex aggregation turbidity assay (latex) and a conventional enzyme-linked immunosorbent assay (E-plate), both containing Japanese H. pylori protein lysates as antigens, using sera from seven Asian countries.

METHODS

Serum samples (1797) were obtained, and standard H. pylori infection status and atrophy status were determined by culture and histology (immunohistochemistry) using gastric biopsy samples from the same individuals. The two tests (enzyme-linked immunosorbent assay and latex) were applied, and receiver operating characteristics analysis was performed.

RESULTS

Area under the curve (AUC) from the receiver operating characteristic of E-plate and latex curves were almost the same and the highest in Vietnam. The latex AUC was slightly lower than the E-plate AUC in other countries, and the difference became statistically significant in Myanmar and then Bangladesh as the lowest. To consider past infection cases, atrophy was additionally evaluated. Most of the AUCs decreased using this atrophy-evaluated status; however, the difference between the two kits was not significant in each country, but the latex AUC was better using all samples. Practical cut-off values were 3.0 U/mL in the E-test and 3.5 U/mL in the latex test, to avoid missing gastric cancer patients to the greatest extent possible.

CONCLUSIONS

The kits were applicable in all countries, but new kits using regional H. pylori strains are recommended for Myanmar and Bangladesh. Use of a cut-off value lower than the best cut-off value is essential for screening gastric cancer patients.

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.

Development and validation of a serum microRNA biomarker panel for detecting gastric cancer in a high-risk population

OBJECTIVE

An unmet need exists for a non-invasive biomarker assay to aid gastric cancer diagnosis. We aimed to develop a serum microRNA (miRNA) panel for identifying patients with all stages of gastric cancer from a high-risk population.

DESIGN

We conducted a three-phase, multicentre study comprising 5248 subjects from Singapore and Korea. Biomarker discovery and verification phases were done through comprehensive serum miRNA profiling and multivariant analysis of 578 miRNA candidates in retrospective cohorts of 682 subjects. A clinical assay was developed and validated in a prospective cohort of 4566 symptomatic subjects who underwent endoscopy. Assay performance was confirmed with histological diagnosis and compared with Helicobacter pylori (HP) serology, serum pepsinogens (PGs), 'ABC' method, carcinoembryonic antigen (CEA) and cancer antigen 19-9 (CA19-9). Cost-effectiveness was analysed using a Markov decision model.

RESULTS

We developed a clinical assay for detection of gastric cancer based on a 12-miRNA biomarker panel. The 12-miRNA panel had area under the curve (AUC)=0.93 (95% CI 0.90 to 0.95) and AUC=0.92 (95% CI 0.88 to 0.96) in the discovery and verification cohorts, respectively. In the prospective study, overall sensitivity was 87.0% (95% CI 79.4% to 92.5%) at specificity of 68.4% (95% CI 67.0% to 69.8%). AUC was 0.848 (95% CI 0.81 to 0.88), higher than HP serology (0.635), PG 1/2 ratio (0.641), PG index (0.576), ABC method (0.647), CEA (0.576) and CA19-9 (0.595). The number needed to screen is 489 annually. It is cost-effective for mass screening relative to current practice (incremental cost-effectiveness ratio=US$44 531/quality-of-life year).

CONCLUSION

We developed and validated a serum 12-miRNA biomarker assay, which may be a cost-effective risk assessment for gastric cancer.

TRIAL REGISTRATION NUMBER

This study is registered with ClinicalTrials.gov (Registration number: NCT04329299).

Chronic atrophic gastritis: an update on diagnosis

Background and aim

Atrophic gastritis is a precancerous gastric lesion, therefore its early detection is a priority in preventing gastric cancer. The aim of the present paper is to develop a narrative synthesis of the present knowledge on diagnostic methods of chronic atrophic gastritis.

Methods

A literature search was carried out on main databases: PubMed, Hinari, SpringerLink and Scopus (Elsevier) for the period 2000–2020. The searched keywords were: chronic atrophic gastritis, intestinal metaplasia and dysplasia + diagnosis. Inclusion criteria were focused on the articles about the invasive and non-invasive diagnosis of chronic atrophic gastritis and of precancerous gastric lesions, intestinal metaplasia and dysplasia; exclusion criteria were articles published before 2000 and those that did not include the proposed theme.

Results

The search returned 575 papers addressing the topic of precancerous lesions. From these, 60 articles were qualified representative for the materials published on the topic of this synthesis article, being those that met the inclusion criteria. The data emphasize the need to use upper digestive endoscopy with biopsies for the diagnosis of chronic atrophic gastritis. However serological diagnosis is available as alternative mainly recommended in follow up.

Conclusions

There are two main methodological approaches for the evaluation of chronic atrophic gastritis as a precancerous gastric lesions: invasive examination, which requires histological analysis of biopsy samples taken during upper digestive endoscopy, being the “gold standard” for diagnosis, and non-invasive serological examination using markers of gastric function.

Precision Medicine Approaches to Prevent Gastric Cancer

Gastric cancer remains one of the most common causes of cancer-related death worldwide, although the incidence is declining gradually. The primary risk factor for gastric cancer is Helicobacter pylori infection. The Kyoto global consensus report recommends eradication of H. pylori in all infected patients. However, because it is difficult to stratify the risk of carcinogenesis among patients with a history of H. pylori infection, annual endoscopic surveillance is performed for everyone after eradication. This review summarizes the current approaches used to screen for novel molecules that could assist in the diagnosis of gastric cancer and reduce mortality. Most well-studied molecules are tissue protein biomarkers expressed by the gastric epithelium and associated with metaplasia-dysplasia-carcinoma sequences. Other strategies focus on the origin of cancer stem cell-related markers, such as CD44, and immune reaction-related markers, such as matrix metallopeptidases. Noninvasive methods such as blood-based approaches are more attractive. Serum pepsinogen levels predict the severity of gastric mucosal atrophy before H. pylori eradication, whereas plasma ghrelin levels are associated with atrophy even after eradication. Cell-free DNAs and RNAs are attractive tools for the early detection of cancer. These ideas could lead to the development of more personalized strategies for cancer prevention based on cutting-edge technologies.

Polymorphisms in Pepsinogen C and miRNA Genes Associate with High Serum Pepsinogen II in Gastric Cancer Patients

Background: Pepsinogen (PG) II (PGII) is a serological marker used to estimate the risk of gastric cancer but how PGII expression is regulated is largely unknown. It has been suggested that PGII expression, from the PGC (Progastricsin) gene, is regulated by microRNAs (miRNA), but how PGII levels vary with Helicobacter pylori (H. pylori) infection and miRNAs genotype remains unclear. Methods: Serum levels of PGI and PGII were determined in 80 patients with gastric cancer and persons at risk for gastric cancer (74 first-degree relatives of patients, 62 patients with autoimmune chronic atrophic gastritis, and 2 patients with dysplasia), with and without H. pylori infection. As control from the general population, 52 blood donors were added to the analyses. Associations between PGII levels and genetic variants in PGC and miRNA genes in these groups were explored based on H. pylori seropositivity and the risk for gastric cancer. The two-dimensional difference in gel electrophoresis (2D-DIGE) and the NanoString analysis of messenger RNA (mRNAs) from gastric cancer tissue were used to determine the pathways associated with increased PGII levels. Results: PGII levels were significantly higher in patients with gastric cancer, and in those with H. pylori infection, than in other patients or controls. A PGI/PGII ratio ≤ 3 was found better than PGI < 25 ng/mL to identify patients with gastric cancer (15.0% vs. 8.8%). For two genetic variants, namely rs8111742 in miR-Let-7e and rs121224 in miR-365b, there were significant differences in PGII levels between genotype groups among patients with gastric cancer (p = 0.02 and p = 0.01, respectively), but not among other study subjects. Moreover, a strict relation between rs9471643 C-allele with H. pylori infection and gastric cancer was underlined. Fold change in gene expression of mRNA isolated from gastric cancer tissue correlated well with polymorphism, H. pylori infection, increased PGII level, and pathway for bacteria cell entry into the host. Conclusions: Serum PGII levels depend in part on an interaction between H. pylori and host miRNA genotypes, which may interfere with the cut-off of PGI/PGII ratio used to identify persons at risk of gastric cancer. Results reported new findings regarding the relation among H. pylori, PGII-related host polymorphism, and genes involved in this interaction in the gastric cancer setting.

Screening for gastric cancer in China: Advances, challenges and visions

Gastric cancer (GC) is one of the major cancers in China and all over the world. Most GCs are diagnosed at an advanced stage with unfavorable prognosis. Along with some other countries, China has developed the government-funded national screening programs for GC and other major cancers. GC screening has been shown to effectively decrease the incidence of and mortality from GC in countries adopting nationwide screening programs (Japan and Korea) and in studies based on selected Chinese populations. The screening of GC relies mostly on gastroendoscopy, the accuracy, reliability and safety of which have been indicated by previous studies. However, considering its invasive screening approach, requirements on skilled endoscopists and pathologists, and a high cost, developing noninvasive methods to amend endoscopic screening would be highly needed. Numerous studies have examined biomarkers for GC screening and the combination of biomarkers involving pepsinogen, gastrin, and Helicobacter pylori antibodies has been proposed for risk stratification, seeking to narrow down the high-risk populations for further endoscopy. Despite all the achievements of endoscopic screening, evidence on appropriate screening age, intervals for repeated screening, novel biomarkers promoting precision prevention, and health economics need to be accumulated to inform policymakers on endoscopic screening in China. With the guide of Health China 2030 Planning Outline, we have golden opportunities to promote prevention and control of GC. In this review, we summarize the characteristics of screening programs in China and other East Asian countries and introduce the past and current approaches and strategies for GC screening, aiming for featuring the latest advances and key challenges, and illustrating future visions of GC screening.

Human gastric cancer risk screening: From rat pepsinogen studies to the ABC method

We examined the development of gastric cancer risk screening, from rat pepsinogen studies in an experimental rat gastric carcinogenesis model induced with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and human pepsinogen studies in the 1970s and 1980s to the recent "ABC method" for human gastric cancer risk screening. First, decreased expression or absence of a major pepsinogen isozyme, PG1, was observed in the rat gastric mucosa from the early stages of gastric carcinogenesis to adenocarcinomas following treatment with MNNG. In the 1980s, decreases in PGI in the human gastric mucosa and serum were identified as markers of atrophic gastritis. In the 1990s, other researchers revealed that chronic infection with Helicobacter pylori (Hp) causes atrophic gastritis and later gastric cancer. In the 2000s, a gastric cancer risk screening method combining assays to detect serum anti-Hp IgG antibody and serum PGI and PGII levels, the "ABC method", was established. Eradication of Hp and endoscopic follow-up examination after the ABC method are recommended to prevent gastric cancer.

Effect and cost-effectiveness of national gastric cancer screening in Japan: a microsimulation modeling study

BACKGROUND

A national endoscopic screening program for gastric cancer was rolled out in Japan in 2015. We used a microsimulation model to estimate the cost-effectiveness of current screening guidelines and alternative screening strategies in Japan.

METHODS

We developed a microsimulation model that simulated a virtual population corresponding to the Japanese population in risk factor profile and life expectancy. We evaluated 15 endoscopic screening scenarios with various starting ages, stopping ages, and screening intervals. The primary outcomes were quality-adjusted life-years (QALYs), costs, and incremental cost-effectiveness ratio. Cost-effective screening strategies were determined using a willingness-to-pay threshold of $50,000 per QALY gained. One-way sensitivity and probabilistic sensitivity analyses were done to explore model uncertainty.

RESULTS

Using the threshold of $50,000 per QALY, a triennial screening program for individuals aged 50 to 75 years was the cost-effective strategy, with an incremental cost-effectiveness ratio of $45,665. Compared with no endoscopic screening, this strategy is predicted to prevent 63% of gastric cancer mortality and confer 27.2 QALYs gained per 1000 individuals over a lifetime period. Current screening guidelines were not on the cost-effectiveness efficient frontier. The results were robust on one-way sensitivity analyses and probabilistic sensitivity analysis.

CONCLUSIONS

This modeling study suggests that the endoscopic screening program in Japan would be cost-effective when implemented between age 50 and 75 years, with the screening repeated every 3 years. These findings underscore the need for further evaluation of the current gastric cancer screening recommendations.

Prevalence of atrophic gastritis in southwest China and predictive strength of serum gastrin-17: A cross-sectional study (SIGES)

A hospital-based cross-sectional study in SIGES project was conducted during 2016.5-2017.5 in West China Hospital. It was aimed to observe the prevalence of atrophic gastritis (AG) in southwest China, and assess the diagnostic strength of serum gastrin-17 (G-17) in predicting AG in Chinese population. Asymptomatic healthy controls from health check-up, cancer-free patients with unspecific upper gastrointestinal symptoms, and histologically proven gastric cancer patients were eligible, if serum pepsinogen-I (PG-I), PG-II, and G-17 were detected. AG status was classified by the accredited cutoffs of PG-I (<70 ug/L) and PG-I/II ratio (<3). Totally, healthy controls (n = 9,425), symptomatic patients (n = 671) and gastric cancer patients (n = 305) were simultaneously observed, in which the prevalence of AG in southwest China were estimated as 15.9/1,000, 28.3/1,000, and 55.7/1,000 persons, respectively. The age-specific prevalence of AG in healthy controls showed a significantly uphill trend (p for trend <0.001). Higher level of serum G-17 was significantly associated with increased risk of AG in healthy population (15-30 pmol/L, aOR = 20.67, 95% CI 9.17-46.55; >30 pmol/L, aOR = 314.41, 95% CI 166.10-595.12). Throughout the progression of stomach diseases, the diagnostic strength of serum G-17 for AG showed a downhill trend across more advanced situations. In despite of that, serum G-17 displayed a good performance in predicting AG in the entire cross-sectional population (AUC = 0.92, 95% CI 0.89-0.94; SEN = 85.5%; SPE = 93.2%; LR+ = 12.55; LR- = 0.11). Population in southwest China had intermediate prevalence of AG, while the prevalence was increased over age or disease progression. High level of serum G-17 might be a reliable non-invasive measurement to predict AG in southwest Chinese population.

Previous Helicobacter pylori infection-induced atrophic gastritis: A distinct disease entity in an understudied population without a history of eradication

Individuals with chronic atrophic gastritis who are negative for active H. pylori infection with no history of eradication therapy have been identified in clinical practice. By excluding false-negative and autoimmune gastritis cases, it can be surmised that most of these patients have experienced unintentional eradication of H. pylori after antibiotic treatment for other infectious disease, unreported successful eradication, or H. pylori that spontaneously disappeared. These patients are considered to have previous H. pylori infection-induced atrophic gastritis. In this work, we define these cases based on the following criteria: absence of previous H. pylori eradication; atrophic changes on endoscopy or histologic confirmation of glandular atrophy; negative for a current H. pylori infection diagnosed in the absence of proton-pump inhibitors or antibiotics; and absence of localized corpus atrophy, positivity for autoantibodies, or characteristic histologic findings suggestive of autoimmune gastritis. The risk of developing gastric cancer depends on the atrophic grade. The reported rate of developing gastric cancer is 0.31%-0.62% per year for successfully eradicated severely atrophic cases (pathophysiologically equal to unintentionally eradicated cases and unreported eradicated cases), and 0.53%-0.87% per year for spontaneously resolved cases due to severe atrophy. Therefore, for previous H. pylori infection-induced atrophic gastritis cases, we recommend endoscopic surveillance every 3 years for high-risk patients, including those with endoscopically severe atrophy or intestinal metaplasia. Because of the difficulty involved in the endoscopic diagnosis of gastric cancer in cases of previous infection, appropriate monitoring of the high-risk subgroup of this understudied population is especially important.

Feasibility of combined screening for upper gastrointestinal adenocarcinoma risk by serology and Cytosponge testing: the SUGAR study

AIMS

Aim was to assess the feasibility of serum markers to identify individuals at risk for gastro-oesophageal adenocarcinoma to reduce the number of individuals requiring invasive assessment by endoscopy.

METHODS

Blood samples from 56 patients with Barrett's oesophagus and 202 non-Barrett controls who previously took part in a trial assessing the accuracy of the Cytosponge for Barrett's oesophagus were assessed for serum pepsinogen (PG) 1 and 2, gastrin-17, trefoil factor 3 (TFF3) and Helicobacter pylori infection.

RESULTS

PG1 was pathological (<50 ng/mL) in 26 patients (10.1%), none of whom had Barrett's oesophagus (p<0.001). Smoking and drinking had no influence on these results. Pathological PG1 was associated with stomach pain (p=0.029), disruption of sleep (p=0.027) and disruption of diet by symptoms (p=0.019). Serum TFF3 was not associated with any clinical parameter.

CONCLUSIONS

Assessment of serum PG1 could be combined with a test for Barrett's oesophagus to identify additional patients requiring endoscopy.

British Society of Gastroenterology guidelines on the diagnosis and management of patients at risk of gastric adenocarcinoma

Gastric adenocarcinoma carries a poor prognosis, in part due to the late stage of diagnosis. Risk factors include Helicobacter pylori infection, family history of gastric cancer-in particular, hereditary diffuse gastric cancer and pernicious anaemia. The stages in the progression to cancer include chronic gastritis, gastric atrophy (GA), gastric intestinal metaplasia (GIM) and dysplasia. The key to early detection of cancer and improved survival is to non-invasively identify those at risk before endoscopy. However, although biomarkers may help in the detection of patients with chronic atrophic gastritis, there is insufficient evidence to support their use for population screening. High-quality endoscopy with full mucosal visualisation is an important part of improving early detection. Image-enhanced endoscopy combined with biopsy sampling for histopathology is the best approach to detect and accurately risk-stratify GA and GIM. Biopsies following the Sydney protocol from the antrum, incisura, lesser and greater curvature allow both diagnostic confirmation and risk stratification for progression to cancer. Ideally biopsies should be directed to areas of GA or GIM visualised by high-quality endoscopy. There is insufficient evidence to support screening in a low-risk population (undergoing routine diagnostic oesophagogastroduodenoscopy) such as the UK, but endoscopic surveillance every 3 years should be offered to patients with extensive GA or GIM. Endoscopic mucosal resection or endoscopic submucosal dissection of visible gastric dysplasia and early cancer has been shown to be efficacious with a high success rate and low rate of recurrence, providing that specific quality criteria are met.

[Advances in serum biomarkers for early diagnosis of gastric cancer]

Early diagnosis is the key to improve the prognosis of gastric cancer. How to screen out high-risk subjects of gastric cancer in population is a hot spot. Serum-based early detection of gastric cancer is suitable for high-risk population screening, which is more convenient and safer. This article reviews the diagnostic value of serum biomarkers for gastric cancer, including serum DNA methylation, various RNAs, pepsinogen, gastrin, osteopontin, MG7-Ag and CA724. Until now, there is still lack of ideal biomarkers for gastric cancer, and searching for specific RNAs may be promising for early diagnosis and screening of gastric cancer.

Prediction of Chronic Atrophic Gastritis and Gastric Neoplasms by Serum Pepsinogen Assay: A Systematic Review and Meta-Analysis of Diagnostic Test Accuracy

Serum pepsinogen assay (sPGA), which reveals serum pepsinogen (PG) I concentration and the PG I/PG II ratio, is a non-invasive test for predicting chronic atrophic gastritis (CAG) and gastric neoplasms. Although various cut-off values have been suggested, PG I ≤70 ng/mL and a PG I/PG II ratio of ≤3 have been proposed. However, previous meta-analyses reported insufficient systematic reviews and only pooled outcomes, which cannot determine the diagnostic validity of sPGA with a cut-off value of PG I ≤70 ng/mL and/or PG I/PG II ratio ≤3. We searched the core databases (MEDLINE, Cochrane Library, and Embase) from their inception to April 2018. Fourteen and 43 studies were identified and analyzed for the diagnostic performance in CAG and gastric neoplasms, respectively. Values for sensitivity, specificity, diagnostic odds ratio, and area under the curve with a cut-off value of PG I ≤70 ng/mL and PG I/PG II ratio ≤3 to diagnose CAG were 0.59, 0.89, 12, and 0.81, respectively and for diagnosis of gastric cancer (GC) these values were 0.59, 0.73, 4, and 0.7, respectively. Methodological quality and ethnicity of enrolled studies were found to be the reason for the heterogeneity in CAG diagnosis. Considering the high specificity, non-invasiveness, and easily interpretable characteristics, sPGA has potential for screening of CAG or GC.

Gastric Cancer Screening by Combined Determination of Serum Helicobacter pylori Antibody and Pepsinogen Concentrations: ABC Method for Gastric Cancer Screening

Objective:

Gastroscopy combined with gastric mucosa biopsies is currently regarded as a gold standard for diagnosis of gastric cancer. However, its application is restricted in clinical practice due to its invasive property. A new noninvasive population screening process combining the assay of anti-Helicobacter pylori antibody and serum pepsinogen (PG) (ABC method) is adopted to recognize the high-risk patients for further endoscopy examination, avoiding the unnecessary gastroscopy for most population and saving the cost consumption for mass screening annually. Nevertheless, controversies exist for the grouping of ABC method and the intervals of gastroscopy surveillance for each group. In this review, we summarized these popular concerned topics for providing useful references to the healthcare practitioner in clinical practice.

Data Sources:

The PubMed databases were systematically searched from the inception dates to November 22, 2017, using the keywords “Helicobacter pylori,” “Pepsinogens,” and “Stomach Neoplasms.”

Study Selection:

Original articles and reviews on the topics were selected.

Results:

Anti-H. pylori antibody and serum PG concentration showed significant changes under the different status of H. pylori infection and the progression of atrophic gastritis, which can be used for risk stratification of gastric cancer in clinic. In addition, anti-H. pylori antibody titer can be used for further risk stratification of gastric cancer contributing to determine better endoscopy surveillance interval.

Conclusions:

The early detection and diagnosis of gastric cancer benefit from the risk stratification, but the cutoff values for H. pylori antibody and serum PG concentration require further modification.

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.

Predicting the Development of Gastric Neoplasms in a Healthcare Cohort by Combining Helicobacter pylori Antibodies and Serum Pepsinogen: A 5-Year Longitudinal Study

Background

Helicobacter pylori (HP) and gastric atrophy are risk factors for gastric cancer. We evaluated whether the combination of serum HP antibody and pepsinogen (PG), which is indicative of gastric atrophy, could serve as a predictive marker for the development of gastric neoplasms in a Korean population.

Methods

The subjects who had undergone health-screening examination with endoscopic follow-ups were classified into the following 4 groups according to serum PG status and HP antibody at baseline: group A (HP (-), normal PG), group B (HP (+), normal PG), group C (HP (+), atrophic PG), and group D (HP (-), atrophic PG). We compared the development of gastric neoplasms among the groups.

Results

Of the 3297 subjects, 1239 (37.6%) were categorized as group A, 1484 (45.0%) as group B, 536 (16.3%) as group C, and 38 (1.2%) as group D. During the 5.6 years of mean follow-up period, the annual incidence of gastric neoplasms increased gradually by 0.06% in group A, 0.16% in group B, 0.38% in group C, and 0.49% in group D. A Cox proportional hazard model showed increased development of gastric neoplasms according to group (P for trend = 0.025). Compared to group A, the hazard ratio was 8.25 for group D (95% confidence interval 0.2-74.24), 5.35 for group C (1.68-17.05), and 2.65 for group B (0.86-8.14).

Conclusion

The combination of serum PG and HP antibody is useful for predicting the development of gastric neoplasms, including cancer and adenoma, in a Korean population using endoscopic surveillance.

Development and validation of a risk assessment tool for gastric cancer in a general Japanese population

BACKGROUND

There have been very few reports of risk score models for the development of gastric cancer. The aim of this study was to develop and validate a risk assessment tool for discerning future gastric cancer risk in Japanese.

METHODS

A total of 2444 subjects aged 40 years or over were followed up for 14 years from 1988 (derivation cohort), and 3204 subjects of the same age group were followed up for 5 years from 2002 (validation cohort). The weighting (risk score) of each risk factor for predicting future gastric cancer in the risk assessment tool was determined based on the coefficients of a Cox proportional hazards model in the derivation cohort. The goodness of fit of the established risk assessment tool was assessed using the c-statistic and the Hosmer-Lemeshow test in the validation cohort.

RESULTS

During the follow-up, gastric cancer developed in 90 subjects in the derivation cohort and 35 subjects in the validation cohort. In the derivation cohort, the risk prediction model for gastric cancer was established using significant risk factors: age, sex, the combination of Helicobacter pylori antibody and pepsinogen status, hemoglobin A1c level, and smoking status. The incidence of gastric cancer increased significantly as the sum of risk scores increased (P trend < 0.001). The risk assessment tool was validated internally and showed good discrimination (c-statistic = 0.76) and calibration (Hosmer-Lemeshow test P = 0.43) in the validation cohort.

CONCLUSIONS

We developed a risk assessment tool for gastric cancer that provides a useful guide for stratifying an individual's risk of future gastric cancer.

Cost-effectiveness of combined serum anti-Helicobacter pylori IgG antibody and serum pepsinogen concentrations for screening for gastric cancer risk in Japan

BACKGROUND

A combination of assays for the presence of serum anti-Helicobacter pylori IgG antibody (HPA) and serum pepsinogen (PG) concentrations can be used to screen for gastric cancer risk. In Japan, this "ABC method" is considered an effective means of stratifying gastric cancer risk. This study aimed to ascertain its cost-effectiveness for assessing gastric cancer risk.

METHODS

A Markov model was constructed to compare the cost-effectiveness of two strategies for gastric cancer-risk screening over a 30-year period: the ABC method, which uses a combination of assessing the presence of HPA and measuring serum PG concentrations and scheduling endoscopies accordingly, and annual endoscopic screening. Clinical and epidemiological data on variables in the model were obtained from published reports. Analyses were made from the perspective of the Japanese health care payer.

RESULTS

According to base-case analysis, the ABC method cost less than annual endoscopic screening (64,489 vs. 64,074 USD) and saved more lives (18.16 vs. 18.30 quality-adjusted life years). One-way analyses confirmed the robustness of the cost-effectiveness results. The probability that the ABC method is cost-effective in Japanese individuals aged 50 years was 0.997.

CONCLUSIONS

A combination of HPA and serum PG assays, plus scheduling endoscopy accordingly, is a cost-effective method of screening for gastric cancer risk in Japan.

Western long-term accuracy of serum pepsinogen-based gastric cancer screening

BACKGROUND

Even though mass gastric cancer screening is controversial in Western countries, diverse strategies have been proposed in intermediate-risk to high-risk areas.

AIM

The aim of this study was to determine the long-term accuracy of the pepsinogen test (PG) for early diagnosis of gastric cancer.

PARTICIPANTS AND METHODS

A cohort of inhabitants from the Northern part of Portugal, aged between 40 and 74 years (n=5913), subjected to the PG test (PGI≤70 ng/ml and PGI/PGII≤3), were followed up between November 2006 and December 2015. The diagnosis of gastric cancer was determined through linkage to the population-based registry of cancer [North Region Cancer Registry of Portugal (RORENO)].

RESULTS

Twenty-six gastric cancers were diagnosed (0.4%): nine (4%) among individuals 'positive' for the PG test (n=225) and 15 (0.3%) among those who were 'negative' (n=5688) [hazard ratio=12.7; 95% confidence interval (CI): 5.6-28.6]. Individuals with a 'negative PG test' had a 3-year risk of gastric cancer of 0.1%, representing a sensitivity of 35% (95% CI: 17-56%), globally, and of 58% (95% CI: 28-85%) at 3 years follow-up. The median survival rate in both groups was over 24 months.

CONCLUSION

The PG test was found to be suboptimal as a screening test and, if used (before upper gastrointestinal endoscopy), it is mandatory to repeat it after 3 years.

Serum pepsinogen 1 and anti-Helicobacter pylori IgG antibodies as predictors of gastric cancer risk in Finnish males

BACKGROUND

Serum pepsinogen 1 (SPG1) and anti-Helicobacter pylori serology have been used for gastric risk stratification in Asia.

AIM

To assess utility of these markers in a Western population.

METHODS

SPG1 measurements were available for 21 895 Finnish male smokers in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study. We used Cox proportional hazards models adjusted for potential confounders to estimate gastric cancer hazard ratios (HR) and 95% confidence intervals (95% CI) for low SPG1 (<25 μg/L). In a subset (n = 3555) with anti-H. pylori serology, these markers jointly defined the following: Group A (H. pylori[-], SPG1[normal]; reference group), Group B (H. pylori[+], SPG1[normal]), Group C (H. pylori[+], SPG1[low]) and Group D (H. pylori[-], SPG1[low]). Odds ratios (ORs) and 95% CI were calculated using multivariate logistic regression.

RESULTS

There were 329 gastric cancers diagnosed an average of 13.9 years after baseline. Pre-diagnostic low SPG1 was significantly associated with increased gastric cancer risk (HR 2.68, 95% CI 1.99-3.61). Among subjects with both SPG1 and H. pylori serology, groups B, C and D had increased gastric cancer ORs (95% CI) of 1.79 (1.21-2.64), 3.85 (2.36-6.28) and 6.35 (2.20-18.34), respectively. CagA seropositives had significantly higher ORs than CagA seronegatives within group B (P_{heterogeneity}  = 0.01). For groups B and C, repeat SPG1 level at 3 years did not further stratify gastric cancer risk.

CONCLUSIONS

Low SPG1 was associated with increased gastric cancer risk in our large Finnish cohort. A single measurement of SPG1 along with H. pylori whole cell and CagA serology provides potentially useful prediction of gastric cancer risk.

The serum pepsinogen levels for risk assessment of gastric neoplasms: New proposal from a case-control study in Korea

To decrease the gastric cancer related mortality rate, endoscopic screening is widely performed in Korea. However, a precise method for identifying those at a high risk of gastric neoplasms has not been established. This study aims to evaluate serum pepsinogen (PG) levels for risk assessment of gastric neoplasms. Between August 2014 and March 2016, a total of 398 subjects, including 87 with gastric neoplasms, were enrolled in this study. On the basis of the serum PG I/II ratio, the enrolled subjects were classified into 4 groups: group A, PG I/II ratio >4; group B, >3 and ≤4; group C, >2 and ≤3; group D, ≤2. Compared with group A, a stepwise increase in the risk of gastric neoplasm was observed from group B [odds ratio (OR) = 9.9, 95% confidence interval (95% CI) = 4.0-24.4] to group C (OR = 20.9, 95% CI = 8.7-50.5) to group D (OR = 37.3, 95% CI = 14.3-97.4). The optimal cutoff value of the serum PG I/II ratio for predicting gastric neoplasms was 4.5, with a sensitivity of 97.7% and a specificity of 57.6%. A decrease in the serum PG I/II ratio was strongly associated with an increased risk of gastric neoplasms. The serum PG I/II ratio can be used to identify those at a high risk of gastric neoplasms in Korean population.

Epithelial–mesenchymal transition and gastric cancer stem cell

Gastric cancer remains a big health problem in China. Gastric cancer cells contain a small subpopulation of cells that exhibit capabilities of differentiation and tumorigenicity. A putative explanation for ineffective therapy is the presence of cancer stem-like cells. Side population cells, which have cancer stem-like cells’ property, are characterized by the high efflux ability of Hoechst 33342 dye. Side population cells have been isolated from gastric cancer cell lines in previous studies. The epithelial–mesenchymal transition is very important in the invasion and metastasis of epithelial-derived cancers. More and more studies showed that gastric cancer stem-like cells possess high invasive ability and epithelial–mesenchymal transition property. A brief overview of the recent advancements in gastric cancer stem-like cells and epithelial–mesenchymal transition will be helpful for providing novel insight into gastric cancer treatment.

Host pathogen interactions in Helicobacter pylori related gastric cancer

Helicobacter pylori (H. pylori), discovered in 1982, is a microaerophilic, spiral-shaped gram-negative bacterium that is able to colonize the human stomach. Nearly half of the world's population is infected by this pathogen. Its ability to induce gastritis, peptic ulcers, gastric cancer and mucosa-associated lymphoid tissue lymphoma has been confirmed. The susceptibility of an individual to these clinical outcomes is multifactorial and depends on H. pylori virulence, environmental factors, the genetic susceptibility of the host and the reactivity of the host immune system. Despite the host immune response, H. pylori infection can be difficult to eradicate. H. pylori is categorized as a group I carcinogen since this bacterium is responsible for the highest rate of cancer-related deaths worldwide. Early detection of cancer can be lifesaving. The 5-year survival rate for gastric cancer patients diagnosed in the early stages is nearly 90%. Gastric cancer is asymptomatic in the early stages but always progresses over time and begins to cause symptoms when untreated. In 97% of stomach cancer cases, cancer cells metastasize to other organs. H. pylori infection is responsible for nearly 60% of the intestinal-type gastric cancer cases but also influences the development of diffuse gastric cancer. The host genetic susceptibility depends on polymorphisms of genes involved in H. pylori-related inflammation and the cytokine response of gastric epithelial and immune cells. H. pylori strains differ in their ability to induce a deleterious inflammatory response. H. pylori-driven cytokines accelerate the inflammatory response and promote malignancy. Chronic H. pylori infection induces genetic instability in gastric epithelial cells and affects the DNA damage repair systems. Therefore, H. pylori infection should always be considered a pro-cancerous factor.

Evaluation of Pepsinogen I as a Biomarker of Drug-induced Gastric Mucosal Injury in Cynomolgus Monkeys

Gastric mucosal injury is frequently observed in nonclinical studies of nonhuman primates. Because microscopic evaluation of stomach is generally a terminal procedure, our objective was to determine whether serum pepsinogen I (PG I) could serve as a noninvasive biomarker for detection of gastric mucosal injury in monkey. Serum PG I was measured using a commercial human immunoassay in cynomolgus monkeys ( n = 166) prior to dosing and/or terminally in 11 studies of up to 1 month duration. Mean ( SD) PG I values (ug/L) for monkeys with ( n = 59) and without ( n = 100) gastric mucosal degeneration were 101 (215) and 28 (12.6), respectively. For monkeys with baseline and terminal PG I data, mean ( SD) fold change (ratio of terminal to baseline PG I) for monkeys with ( n = 57) and without ( n = 76) glandular degeneration were 4.1 (11.3) and 1 (0.28). Receiver operating characteristic area under the curve (AUC) data demonstrated moderate diagnostic accuracy for serum PG I for glandular degeneration, AUC ( SE) 0.789 (0.04), with improved diagnostic accuracy as a fold change of baseline, AUC ( SE) 0.816 (0.04), consistent with the large interindividual but low intraindividual variability of serum PG I values in control monkeys. These data demonstrate that serum PG I is a useful biomarker of drug-induced gastric mucosal injury in the cynomolgus monkey.