The benefit of mass eradication of Helicobacter pylori infection: a community-based study of gastric cancer prevention

Effects of alcohol consumption, cigarette smoking, and betel quid chewing on upper digestive diseases: a large cross-sectional study and meta-analysis

Cigarette smoking is a well-known risk factor of upper digestive diseases. Findings on alcohol's effect on these diseases are inconsistent and with the exception of its association with esophageal cancer, little is known about betel quid chewing. This study investigated the association between use of these three substances and upper digestive diseases. We collected data from 9,275 patients receiving upper endoscopies between April 2008 and December 2013. Polynomial regressions were used to analyze the association between risk factors and diseases of the esophagus, stomach and duodenum. Meta-analysis for use of these substances and esophageal diseases was also performed. Participants who simultaneously consumed cigarettes, alcohol and betel quid had a 17.28-fold risk of esophageal cancer (95% CI = 7.59-39.33), 2.99-fold risk of Barrette's esophagus (95% CI = 2.40-4.39), 1.60-fold risk of grade A-B erosive esophagitis (95% CI = 1.29-2.00), 2.00-fold risk of gastric ulcer (95% CI = 1.52-2.63), 2.12-fold risk of duodenitis (95% CI = 1.55-2.89) and 1.29-fold risk of duodenal ulcer (95% CI = 1.01-1.65). Concurrent consumption of more substances was associated with significantly higher risk of developing these diseases. Meta-analysis also revealed use of the three substances came with a high risk of esophageal diseases. In conclusions, cigarette smoking, alcohol drinking and betel quid chewing were associated with upper digestive tract diseases.

Prevention of Gastric Cancer: Eradication of Helicobacter Pylori and Beyond

Although its prevalence is declining, gastric cancer remains a significant public health issue. The bacterium Helicobacter pylori is known to colonize the human stomach and induce chronic atrophic gastritis, intestinal metaplasia, and gastric cancer. Results using a Mongolian gerbil model revealed that H. pylori infection increased the incidence of carcinogen-induced adenocarcinoma, whereas curative treatment of H. pylori significantly lowered cancer incidence. Furthermore, some epidemiological studies have shown that eradication of H. pylori reduces the development of metachronous cancer in humans. However, other reports have warned that human cases of atrophic metaplastic gastritis are already at risk for gastric cancer development, even after eradication of these bacteria. In this article, we discuss the effectiveness of H. pylori eradication and the morphological changes that occur in gastric dysplasia/cancer lesions. We further assess the control of gastric cancer using various chemopreventive agents.

Long-term effect of Helicobacter pylori eradication combined with folate in patients with chronic atrophic gastritis

AIM

To investigate the long-term effect of Helicobacter pylori (H. pylori) eradication combined with folate in patients with chronic atrophic gastritis (CAG).

METHODS

One hundred and twenty-three patients who underwent H. pylori eradication from July 2013 to June 2014 at our hospital were enrolled and divided into a combination group (n = 71) and a single eradication group (n = 52). Patients in the single eradication group were given standard triple H. pylori eradication therapy, and cases in the combination group were given folate for 3 mo after H. pylori eradication. All cases were followed at 2 years after treatment. The stages of operative link for gastric intestinal metaplasia assessment (OLGIM) and operative link for gastritis assessment (OLGA) were compared between the two groups before and after treatment. Patients in the combination group were further divided into an H. pylori successful eradication group (n = 49) and an H. pylori reinfection group (n = 22) according to the result of ¹³C urea breath test, and CAG lesion score was compared among the three groups before and after treatment.

RESULTS

The stages of OLGIM and OLGA in the combination group were significantly better than those in the single eradication group at 2 years after treatment (P < 0.05). CAG lesion scores in the H. pylori successful eradication group and single eradication group at 2 years after treatment were significantly lower than those before treatment in the same group (P < 0.05), but there was no significant difference in CAG lesion score between before and after treatment in the H. pylori reinfection group (P > 0.05). After treatment, CAG lesion score in the H. pylori successful eradication group was significantly lower than those in the H. pylori reinfection group and single eradication group (P < 0.05), although there was no significant difference in CAG lesion score between the H. pylori reinfection group and single eradication group after treatment (P > 0.05).

CONCLUSION

H. pylori eradication combined with folate treatment could significantly improve gastric mucosal atrophy and intestinal metaplasia in patients with CAG, and promote disease recovery, with satisfactory long-term effect, especially for patients with successful H. pylori eradication.

Osteopontin polymorphism increases gastric precancerous intestinal metaplasia susceptibility in Helicobacter pylori infected male

AIM

Whether genetic polymorphisms of osteopontin (OPN) coding gene, SPP1, determine the risk of gastric precancerous intestinal metaplasia (IM) in Helicobacter pylori infected patients.

PATIENTS & METHODS

Helicobacter pylori infected patients (100 with and 210 without IM) were recruited to evaluate the associations of SPP1 promoter polymorphisms with gastric IM and adjusted for age, sex and smoking. Gastric OPN expression and inflammation were evaluated by immunohistochemistry, and haemotoxylin and eosin stain.

RESULTS

Only in males, but not females, carriage of both GG genotype at rs11730059 and C-G-C haplotype at rs6833161-rs2853744-rs11730582 significantly increased the IM risk (OR: 4.92; 95% CI: 1.65-14.65; p = 0.004). Nearly 87.5% of males with IM carried risky genotype or haplotype. Carriers of the risky genotype or haplotype also had increased gastric OPN expression (p = 0.038) and inflammation (p = 0.007).

CONCLUSION

SPP1 polymorphisms predispose to IM development in H. pylori infected males.

Helicobacter, Hygiene, Atopy, and Asthma

The hygiene hypothesis links environmental and microbial exposures in early life to the prevalence of atopy, allergy, and asthma. Helicobacter pylori infection is typically acquired in childhood and acquisition of the infection is associated with poor household hygiene. Some population surveys have shown an inverse association between H. pylori infection and atopy, allergy, and asthma leading to the suggestion that H. pylori infection may be protective against disease; others consider it simply a biomarker for poor household hygiene. We review the relevant surveys, cohort studies, meta-analyses, and studies testing the protective hypothesis. Overall, the results of surveys and cohort studies are inconsistent, whereas meta-analyses show a significant but weak inverse correlation. In contrast, studies directly testing the protection hypothesis in relation to asthma in populations with poor hygiene and low H. pylori prevalence failed to confirm a protective effect. H. pylori is a major cause of human disease including chronic gastritis, peptic ulcer, and gastric malignancies. H. pylori infections most likely serve as a biomarker for poor hygienic conditions in childhood. We conclude that while synergistic interactions between environmental factors in childhood are important determinants of the pathogenesis of atopy, allergy, and asthma; H. pylori is inversely related to good hygiene and thus it's presence serves as a biomarker rather than for a specific prevention role for H. pylori or H. pylori antigens.

Gastric adenocarcinoma

Gastric cancers, with gastric adenocarcinoma (GAC) as the most common histological type, impose a considerable global health burden. Although the screening strategies for early detection have been shown to be successful in Japan and South Korea, they are either not implemented or not feasible in most of the world, leading to late diagnosis in most patients. Helicobacter pylori infection contributes to the development of many endemic GACs, and pre-emptive eradication or early treatment of this bacterial infection might provide effective primary prevention. GACs are phenotypically and genotypically heterogeneous. Localized (clinical stage I) GAC is best treated either endoscopically or with limited surgical resection, but clinical stage II or stage III tumours require multidisciplinary adjunctive approaches in addition to surgery. Although GAC is highly treatable in its early stages, advanced (clinical stage IV) GAC has a median survival of just ∼9-10 months. However, detailed molecular and immune profiling of GAC is yielding promise; early studies with immune checkpoint inhibitors suggest that GAC is amenable to immune modulation. Molecular studies have yielded a vast quantity of new information for potential exploitation. Nevertheless, advances against GACs have lagged compared with other tumours of similar incidence, and more research is necessary to overcome the obstacles to prolong survival.

Consensus on the clinical management, screening-to-treat, and surveillance of Helicobacter pylori infection to improve gastric cancer control on a nationwide scale

BACKGROUND

Previous international consensus statements provided general policies for the management of Helicobacter pylori infection. However, there are geographic differences in the prevalence and antimicrobial resistance of H. pylori, and in the availability of medications and endoscopy. Thus, nationwide or regional consensus statements are needed to improve control of H. pylori infection and gastric cancer.

MATERIALS AND METHODS

This consensus statement for management of H. pylori in Taiwan has three major sections: (1) optimal diagnosis and indications; (2) current treatment strategies; and (3) screening-to-treat and surveillance for control of gastric cancer. The literature review emphasized recent data for development of draft statements and determination of levels of evidence. Twenty-five Taiwan experts conducted a consensus conference, by a modified Delphi process, to modify the draft statements. Consensus, defined as an agreement of least 80% of the experts, and recommendation grade were determined by anonymous voting.

RESULTS

There were 24 consensus statements. Section 1 has seven statements on recommendations for the diagnosis and indications for treatment of H. pylori infection. Section 2 has 10 statements that provide an updated treatment algorithm for first-line, second-line, and third-line regimens. Section 3 has seven statements regarding H. pylori eradication for reducing the risk of gastric cancer, with a cost-benefit analysis. After H. pylori eradication, the consensus highlights the use of endoscopic surveillance and/or chemoprevention to further reduce the burden of gastric cancer.

CONCLUSIONS

This consensus statement has updated recommendations for improving the clinical management of H. pylori infection in areas such as Taiwan, which have high prevalence of H. pylori infection and gastric cancer.

Screening and treating Helicobacter pylori infection for gastric cancer prevention on the population level

Helicobacter pylori infection is the major cause of gastric cancer, and removal of H. pylori infection from a population could theoretically decrease the number of cases by about 89%. However, in real-life settings, few studies have reported the effect of screening and treating this pathogen in population-based programs. This is mainly because of the lack of an adequate infrastructure for delivery of systematic screening services to asymptomatic individuals, the lack of standardization to ensure that each subject receives the correct diagnostic testing and antibiotic treatment, and limited resources. We illustrate our method of implementing two population-based screen-and-treat programs in Taiwan, where the epidemiological characteristics of disease burden have changed from the traditionally Eastern pattern towards that of the Western countries. Our first example is a high-risk population that resides on an offshore island, in which a strategy of mass eradication of H. pylori was applied. The other example is an intermediate-risk population, which is representative of the general average-risk population, in which there is integration of the screen-and-treat method with the established framework of colorectal cancer screening using the fecal-occult blood test. The information provided here may be useful for integration of gastric cancer prevention measures into the healthcare priorities of populations with different gastric cancer risks, such as those with limited resources.

Therapeutic success with bismuth-containing sequential and quadruple regimens in Helicobacter pylori eradication

BACKGROUND AND STUDY AIMS

The success rate of Helicobacter pylori (H. pylori) eradication with the classical triple therapy is gradually declining. In this study, we aimed to compare and assess the efficacies of six different eradication regimens including sequential protocols.

PATIENTS AND METHODS

Endoscopically confirmed nonulcer dyspepsia patients were enrolled. H. pylori presence was determined either histologically or by a rapid urease test. Treatment-naive patients were randomly assigned to an either one of three 10-day (OAC, OTMB, and OACB) or one of three sequential protocols (OA+OCM, OA+OCMB, and OA+OMDB) (O=omeprazole, A=amoxicillin, C=clarithromycin, T=tetracycline, M=metronidazole, B=bismuth, D=doxycycline). The eradication was assessed 6-8weeks after the completion of the treatment by a 14C-urea breath test.

RESULTS

In total, 301 patients were included. Fifty-two percent of the participants (n=157) were female, and the mean age was 44.9years (range=18-70). The intention to treat (ITT) and per protocol (PP) eradication rate for each regimen is as follows: OAC (ITT=61.2%, PP=75%), OTMB (83.3%, 87%), OACB (76.5%, 79.6%), OA+OCM (72.3%, 73.9%), OA+OCMB (82.7%, 89.6%), and OA+OMDB (59.3%, 65.3%). Smoking significantly affected the eradication rate (P=0.04).

CONCLUSION

In this study, OTMB and OA+OCMB were significantly superior to the triple therapy and succeeded to reach the eradication rate proposed by the Maastricht consensus (over 80%). These two bismuth-containing regimens could be considered for first-line therapy in the regions with high clarithromycin resistance.

幽门螺杆菌根除治疗在胃癌预防中的现状及前景

幽门螺杆菌(Helicobacter pylori, H. pylori)与胃癌(gastric cancer, GC)发生发展密切相关, 根除H. pylori可降低GC发生率. 经济学分析表明, 在高危人群中根除治疗H. pylori作为预防GC的策略是成本效益较好的. 即使在GC低风险人群中, H. pylori筛查和治疗也能使上消化道其他非恶性疾病获益. 然而, 广泛开展H. pylori根除治疗可能带来其他问题, 包括抗生素耐药增加和与H. pylori负相关疾病(如胃食管反流病、Barrett食管、哮喘和肥胖等)的患病率升高. 本文将结合近年最新研究, 就上述问题展开论述, 进一步提出H. pylori根除治疗预防GC所面临的挑战以及将来可能的进展方向.

Novel and Effective Therapeutic Regimens for Helicobacter pylori in an Era of Increasing Antibiotic Resistance

Helicobacter pylori (H. pylori) is a common gastrointestinal bacterial strain closely associated with the incidence of chronic gastritis, peptic ulcers, gastric mucosa-associated lymphoid tissue lymphoma, and gastric cancer. A current research and clinical challenge is the increased rate of antibiotic resistance in H. pylori, which has led to a decreased H. pylori eradication rate. In this article, we review recent H. pylori infection and reinfection rates and H. pylori resistance to antibiotics, and we discuss the pertinent treatments. A PubMed literature search was performed using the following keywords: Helicobacter pylori, infection, reinfection, antibiotic resistance, bismuth, proton pump inhibitors, vonoprazan, susceptibility, quintuple therapy, dual therapy, and probiotic. The prevalence of H. pylori has remained high in some areas despite the decreasing trend of H. pylori prevalence observed over time. Additionally, the H. pylori reinfection rate has varied in different countries due to socioeconomic and hygienic conditions. Helicobacter pylori monoresistance to clarithromycin, metronidazole or levofloxacin was common in most countries. However, the prevalence of amoxicillin and tetracycline resistance has remained low. Because H. pylori infection and reinfection present serious challenges and because H. pylori resistance to clarithromycin, metronidazole or levofloxacin remains high in most countries, the selection of an efficient regimen to eradicate H. pylori is critical. Currently, bismuth-containing quadruple therapies still achieve high eradication rates. Moreover, susceptibility-based therapies are alternatives because they may avoid the use of unnecessary antibiotics. Novel regimens, e.g., vonoprazan-containing triple therapies, quintuple therapies, high-dose dual therapies, and standard triple therapies with probiotics, require further studies concerning their efficiency and safety for treating H. pylori.

A systematic review and meta-analysis of the role of Helicobacter pylori eradication in preventing gastric cancer

BACKGROUND

Increasing evidence has suggested that Helicobacter pylori (H. pylori) eradication might prevent the development of gastric cancer (GC). This systematic review and meta-analysis aimed to better explore the role of H. pylori eradication in preventing GC, with particular reference to patients with precancerous lesions at baseline histology.

METHODS

Searches for human studies were performed through October 2016 and risk ratios (RRs), were obtained. Heterogeneity between studies was estimated using the Cochran Q test and I2 values, whereas the possibility of publication bias was estimated with funnel plots. Additionally, we performed subgroup and sensitivity analyses.

RESULTS

In 26 studies suitable for meta-analysis (10 randomized controlled trials and 16 cohort studies) 52,363 subjects were included. The risk of GC among patients in whom H. pylori was successfully eradicated was significantly lower than that among controls: pooled RRs [95% CI] 0.56 [0.48-0.66], Z= -7.27, P=0.00001. This finding applied separately for randomized controlled trials (0.65 [0.51-0.84], Z= -3.33, P=0.0009) and for cohort studies (0.51 [0.42-0.62], Z= -6.63, P=0.00001). Concerning H. pylori eradication in patients with precancerous lesions, subgroup analyses showed that patients with non-atrophic or atrophic gastritis benefited from H. pylori eradication for the risk of GC development, whereas those with intestinal metaplasia or dysplasia did not.

CONCLUSION

H. pylori eradication is associated with a significantly lower risk of GC; this finding has significant implications for the prevention of this cancer. The benefit is maximized when H. pylori eradication is applied at early stages of the infection.

Population screening and treatment of Helicobacter pylori infection

Helicobacter pylori is an important human pathogen, associated with a substantial burden from both malignant and non-malignant diseases. The bacterium is classed as a human carcinogen, being strongly linked with gastric cancer, the third most common cause of cancer death worldwide and is also associated with common conditions such as dyspepsia and peptic ulcer. Eradication of H. pylori reduces the incidence of gastric cancer and peptic ulcer, as well as the prevalence and costs of managing dyspepsia. Economic analyses suggest that eradication of H. pylori as a means of controlling gastric cancer is cost-effective in high-risk populations. Even in populations at low risk of gastric cancer, there might be other benefits arising from screening and treatment, owing to the effects on non-malignant upper gastrointestinal diseases. However, public health authorities have been slow to consider the benefits of population-based screening and treatment as a means of reducing the morbidity and mortality associated with the infection. There are also concerns about widespread use of eradication therapy, including antimicrobial resistance and a rise in the prevalence of diseases that are negatively associated with H. pylori, such as GERD, Barrett oesophagus, asthma and obesity. This Review summarizes these issues.

The Gastric Microbiome and Its Influence on Gastric Carcinogenesis: Current Knowledge and Ongoing Research

Gastric malignancies are a leading cause of cancer-related death worldwide. At least 2 microbial species are currently linked to carcinogenesis and the development of cancer within the human stomach. These include the bacterium Helicobacter pylori and the Epstein-Barr virus. In recent years, there has been increasing evidence that within the human gastrointestinal tract it is not only pathogenic microbes that impact human health but also the corresponding autochthonous microbial communities. This article reviews the gastrointestinal microbiome as it relates primarily to mechanisms of disease and carcinogenesis within the upper gastrointestinal tract.

TNF-α-308/-238 polymorphisms are associated with gastric cancer: A case-control family study in China

BACKGROUND

Associations of TNF-α-308 (rs1800629) and -238 (rs361525) with gastric cancer had the inconsistent indication among different populations.

METHODS

In this case-control family study, 47 families were determined with the probands diagnosed with gastric cancer (case family, n=296), accordingly 47 families without gastric cancer were matched with the case families by multivariate distribution of age, sex, social class, and pedigree size (control family, n=319). Polymerase chain reaction-restriction fragment length polymorphism (RFLP-PCR) was used to identify the TNF genotype. Chi-square test was used to compare the groups regarding genotype and the allele frequencies, HWE test for Hardy-Weinberg equilibrium.

RESULTS

The frequencies of TNF-α-308 GA and AA genotypes were significantly higher in case family than that in control family. The risk of gastric cancer was increased in GA and AA carriers in the first degree (OR=2.06, 95% CI=1.20-3.51 and OR=4.89, 95% CI=2.74-8.74), however the similar result was not found in the second degree. Helicobacter pylori infection status were significantly associated with risk of gastric cancer in first-degree relatives (OR=1.96, 95% CI=1.26-3.05) while no statistical significance was noted in the second-degree relatives. Haplotypes of TNF-α-308/-238 alleles, GA/GG, AA/GG and AA/GA indicated the susceptibilities to gastric cancer with OR and 95% confident intervals resulting 2.07 (1.34-3.21), 4.49 (2.74-7.33) and 4.98 (1.76-14.01) respectively.

CONCLUSIONS

TNF-α-G308A (rs1800629) polymorphisms are associated with gastric cancer in Chinese population. Haplotypes of TNF-α-308/-238 GA/GG, AA/GG and AA/GA increase the susceptibilities to gastric cancer. The first-degree relatives are more likely to develop into gastric cancer with TNF-α-G308 polymorphisms and H. pylori positive than the second-degree are.

Management of Helicobacter pylori infection-the Maastricht V/Florence Consensus Report

Important progress has been made in the management of Helicobacter pylori infection and in this fifth edition of the Maastricht Consensus Report, key aspects related to the clinical role of H. pylori were re-evaluated in 2015. In the Maastricht V/Florence Consensus Conference, 43 experts from 24 countries examined new data related to H. pylori in five subdivided workshops: (1) Indications/Associations, (2) Diagnosis, (3) Treatment, (4) Prevention/Public Health, (5) H. pylori and the Gastric Microbiota. The results of the individual workshops were presented to a final consensus voting that included all participants. Recommendations are provided on the basis of the best available evidence and relevance to the management of H. pylori infection in the various clinical scenarios.

[New opportunities for the prevention of gastric cancer]

The approvals and provisions of the Management of Helicobacter pylori infection-the Maastricht V/ Florence Consensus Report and those of the Kyoto Global Consensus Conference on H. pylori-associated gastritis, concerning with the primary and secondary prevention of gastric cancer (GC), unambiguously suggest that H. pylori infection is the most important risk factor of GC. Accordingly, the basis for the primary and secondary prevention of GC is the optimization of H. pylori eradication therapy. The clear direct relationship of the risk of GC to the severity and extent of atrophic gastritis, intestinal metaplasia and dysplasia and no reversal of intestinal metaplasia and dysplasia in the presence of H. pylori eradication presume that gastroprotective agents should be used for primary and secondary prevention. Experimental and clinical findings can lead to the conclusion that rebamipide is a highly effective and safe agent for the primary and secondary prevention of GC in patients with and without H. pylori infection, by optimizing anti-Helicobacter therapy, its anti-inflammatory effect and ability to restore the cellular structure of the gastric epithelium.

Evaluating efficacy of screening for upper gastrointestinal cancer in China: a study protocol for a randomized controlled trial

Objective

To evaluate the efficacy and feasibility of screening procedure for upper gastrointestinal cancer in both high-risk and non-high-risk areas in China.

Setting

Seven cities/counties, representing three economical-geographical regions (Eastern, Central and Western) in China, were selected as screening centers: three in high-risk areas and four in non-high-risk areas.

Participants

Villages/communities in these seven centers regarded as clusters were randomly assigned to either intervention group (screening by endoscopic examination) or control group (with normal community care) in a 1:1 ratio stratified by each center. Eligible participants are local residents aged 40–69 years in the selected villages/communities with no history of cancer or endoscopic examination in the latest 3 years who are mentally and physically competent. Those who are not willing to take endoscopic examination or are unwilling to sign the consent form are excluded from the study. Totally 140,000 participants will be enrolled.

Interventions

In high-risk areas of upper gastrointestinal cancer, all subjects in screening group will be screened by endoscopy. In non-high-risk areas, 30% of the subjects in screening group, identified through a survey, will be screened by endoscopy.

Primary and secondary outcome measures

The primary outcome is the mortality caused by upper gastrointestinal cancer. The secondary outcomes include detection rate, incidence rate, survival rate, and clinical stage distribution. Additional data on quality of life and cost-effectiveness will also be collected to answer important questions regarding screening effects.

Conclusions

Screening strategy evaluated in those areas with positive findings may be promoted nationally and applied to the majority of Chinese people. On the other hand, negative findings will provide scientific evidence for abandoning a test and shifting resources elsewhere.

Trial registration

The study has been registered with the Protocol Registration System in Chinese Clinical Trial Registry (identifier: ChiCTR-EOR-16008577).

[Molecular genetic predictors of resistance to anti-Helicobacter pylori therapy]

In current clinical practice, there is no optimal empirical therapy for Helicobacter pylori (H. pylori) infection and there is a progressive decrease in the efficiency of classical eradication therapy (ET) regimens. The variability in the efficiency of ET in a specific patient is largely due to the heterogeneous molecular genetic mechanisms underlying the resistance of the microorganism to the components of the treatment regimens. The basis of the mechanisms for antibiotic resistance in H. pylori is mainly the point mutations in some genes, which determine alterations in the mechanisms of action of drugs, such as clarithromycin (domain V of 23S rRNA), metronidazole (rdxA, frxA), amoxicillin (pbp1A), tetracycline (16S rRNA), and levofloxacin (gyrA). The predictors of resistance to ET are also the CagA-negative status of the microorganism and the presence of the vacA s2 allele. There are a number of host genetic determinants (the CYP2C19 genotype (*1/*1, *1/*17, *17/*17) and the MDR1 3435 T/T genotype (in an Asian population)) that reduce the efficiency of ET, by altering the pharmacokinetics of proton pump inhibitors. In addition, the IL-1β-511 C/C polymorphism that affects gastric acid secretion is a predictor of the inefficiency of ET.

The Clinical Evidence Linking Helicobacter pylori to Gastric Cancer

Gastric cancer has long been recognized to be accompanied and preceded by chronic gastritis, lasting decades. Arguably, the most important development in our understanding of gastric cancer pathogenesis over the past 50 years has been the realization that, for most cases of gastric cancer, Helicobacter pylori is the cause of the underlying gastritis. Gastritis can promote gastric carcinogenesis, typically via the Correa cascade of atrophic gastritis, intestinal metaplasia, and dysplasia. Nested case-control studies have shown that H pylori infection increases the risk of gastric cancer significantly, both of the intestinal and diffuse subtypes, and that H pylori is responsible for approximately 90% of the world's burden of noncardia gastric cancer. Based largely on randomized studies in high gastric cancer prevalence regions in East Asia, it appears that primary and tertiary intervention to eradicate H pylori can halve the risk of gastric cancer. Some public health authorities now are starting screening and treatment programs to reduce the burden of gastric cancer in these high-risk areas. However, there is currently much less enthusiasm for initiating similar attempts in the United States. This is partially because gastric cancer is a relatively less frequent cause of cancer in the United States, and in addition there are concerns about theoretical downsides of H pylori eradication, principally because of the consistent inverse relationship noted between H pylori and esophageal adenocarcinoma. Nevertheless, establishing a link between chronic H pylori infection and gastric cancer has led to novel insights into cancer biology, the gastrointestinal microbiome, and on individual and population-based gastric cancer prevention strategies.

Helicobacter pylori screening: options and challenges

Helicobacter pylori gastritis is the most frequent infectious disease in the gastrointestinal tract. Clinical sequelae of the infection including peptic ulcer disease, sporadic gastric cancer (GC) and primary B-cell gastric lymphoma (MALT-lymphoma) may develop in up to 20% of the infected individuals. The H. pylori screen-and-treat strategy is addressed to members of communities with high GC incidence, and first-degree relatives of GC patients. For primary GC prevention, H. pylori screen-and-treat is most effective in patients without precancerous conditions. In populations at moderate risk, strategies for GC prevention need to be explored. A special clinical scenario for primary and secondary prevention of H. pylori related benign complications are patients on non-steroidal anti-inflammatory drugs and low-dose aspirin. Vaccination represents another option for eliminating H. pylori infection in the population and a new H. pylori vaccine has shown promising results. However, long-term effects with the use of vaccine are not available.

Helicobacter Pylori and Gastric Cancer: Clinical Aspects

Objective:

Although Helicobacter pylori (H. pylori) is considered as the main etiological factor for gastric cancer, the strategy of screening and treating the oncogenic bacterium is still controversial. The objective was to evaluate the status and progress of the cognition about the relationship between H. pylori infection and gastric cancer from a clinical aspect.

Data Sources:

The data used in this review were mainly from the PubMed articles published in English from 1984 to 2015.

Study Selection:

Clinical research articles were selected mainly according to their level of relevance to this topic.

Results:

Gastric cancer is the fifth most common malignancy and the third leading cause of cancer deaths worldwide. The main etiological factor for gastric cancer is H. pylori infection. About 74.7–89.0% gastric cancer was related to H. pylori infection. Up to date, some regional gastric cancer prevention programs including the detection and treatment of H. pylori infection are under way. Current data obtained from the randomized controlled trials suggest that population-based H. pylori screening and treatment is feasible and cost-effective in preventing gastric cancer; however, a population-based H. pylori eradication campaign would potentially lead to bacterial resistance to the corresponding antibiotics, as well as a negative impact on the normal flora.

Conclusions:

The important questions of feasibility, program costs, appropriate target groups for intervention, and the potential harm of mass therapy with antibiotics must first be answered before implementing any large-scale program.

Treatment of Helicobacter pylori infection: Where are we now?

Gastric cancer and Helicobacter pylori infection remain a burden in many Asian countries. In the face of rising antibiotic resistance, the eradication rate of standard triple therapy is declining in many Asian countries. We reviewed the updated epidemiology of gastric cancer, prevalence of H. pylori infection, and antibiotic resistance in Asia. We also reviewed the strategies to improve the efficacy of H. pylori eradication therapies, including the use of high dose proton pump inhibitor, four drug therapies (including bismuth quadruple, concomitant, and sequential therapy), susceptibility guided therapy, extending the treatment duration to 14 days, and development of effective rescue therapy. Four drug therapies are usually more effective than triple therapy when given in the same duration, except in areas with concomitantly high metronidazole resistance and low clarithromycin resistance. The efficacies of different four drug regimens appeared to be similar. However, trials from different geographic areas showed contradictory results, indicating that the optimal therapy should be decided according to the local prevalence of antibiotic resistance. We proposed a prediction model to calculate the efficacy of different regimens according to the prevalence of antibiotic resistance. More large randomized trials which provide information on the antibiotic resistance are urgently needed to build a more accurate and reliable model. It is hoped that we will be able to decide the optimal regimens by routine surveillance of antibiotic resistance.

Effect of Helicobacter pylori Eradication and ABO Genotype on Gastric Cancer Development

BACKGROUND

Evidence is lacking regarding how Helicobacter pylori infection status, eradication history, and ABO blood type affect the development of gastric cancer (GC) given the multifactorial and distinctive etiology according to cancer location (noncardia vs cardia) and histologic type (intestinal vs diffuse-type). We evaluated the effect of H. pylori infection status incorporated with H. pylori eradication history and ABO genotype on GC development according to cancer location and histologic type.

METHODS

A case-control study of 997 patients with noncardia GC (NCGC) and 1147 control subjects was performed using risk analyses with 14 factors including H. pylori infection with eradication history and ABO genotype. As final analyses, multivariable logistic regression models were fitted. Additionally, H. pylori infection status with eradication history was tested for its association with age, atrophic gastritis (AG), and intestinal metaplasia (IM).

RESULTS

The ABO genotype with the B allele was associated with a significantly lower risk of NCGC of both histologic types. The reduction in risk for NCGC by adding the B allele was more prominent in diffuse-type than that in the intestinal-type. H. pylori infection with eradication history was associated with a significantly lower risk of NCGC of both histologic types, compared with those without eradication history (odds ratio (OR), 0.22; 95% confidence interval (CI), 0.14-0.34) approaching that of uninfected subjects. Past infection status without an eradication history was associated with older age, AG, and IM.

CONCLUSIONS

H. pylori eradication and the B allele decreased the risks of the intestinal and diffuse-types of NCGC. H. pylori eradication revealed a strong association against developing NCGC. Therefore, it should be considered as a primary measure in NCGC prevention.

Concomitant, bismuth quadruple, and 14-day triple therapy in the first-line treatment of Helicobacter pylori: a multicentre, open-label, randomised trial

BACKGROUND

Whether concomitant therapy is superior to bismuth quadruple therapy or 14-day triple therapy for the first-line treatment of Helicobacter pylori infection remains poorly understood. We aimed to compare the efficacy and safety of 10-day concomitant therapy, 10-day bismuth quadruple therapy, and 14-day triple therapy in the first-line treatment of H pylori.

METHODS

In this multicentre, open-label, randomised trial, we recruited adult patients (aged >20 years) with H pylori infection from nine medical centres in Taiwan. Patients who had at least two positive tests from the rapid urease test, histology, culture, or serology or who had a single positive ¹³C-urea breath test for gastric cancer screening were eligible for enrolment. Patients were randomly assigned (1:1:1) to either concomitant therapy (lansoprazole 30 mg, amoxicillin 1 g, clarithromycin 500 mg, and metronidazole 500 mg, all given twice daily) for 10 days; bismuth quadruple therapy (bismuth tripotassium dicitrate 300 mg four times a day, lansoprazole 30 mg twice daily, tetracycline 500 mg four times a day, and metronidazole 500 mg three times a day) for 10 days; or triple therapy (lansoprazole 30 mg, amoxicillin 1 g, and clarithromycin 500 mg, all given twice daily) for 14 days. A computer-generated permuted block randomisation sequence with a block size of 6 was used for randomisation, and the sequence was concealed in an opaque envelope until the intervention was assigned. Investigators were masked to treatment allocation. The primary outcome was the eradication frequency of H pylori with first-line therapy assessed in the intention-to-treat population. This trial is registered with ClinicalTrials.gov, number NCT01906879.

FINDINGS

Between July 17, 2013, and April 20, 2016, 5454 patients were screened for eligibility. Of these, 1620 patients were randomly assigned in this study. The eradication frequencies were 90·4% (488/540 [95% CI 87·6-92·6]) for 10-day bismuth quadruple therapy, 85·9% (464/540 [82·7-88·6]) for 10-day concomitant therapy, and 83·7% (452/540 [80·4-86·6]) for 14-day triple therapy in the intention-to-treat analysis. 10-day bismuth quadruple therapy was superior to 14-day triple therapy (difference 6·7% [95% CI 2·7-10·7, p=0·001), but not 10-day concomitant therapy. 10-day concomitant therapy was not superior to 14-day triple therapy. The frequency of adverse events was 67% (358/533) in patients treated with 10-day bismuth quadruple therapy, 58% (309/535) in patients treated with 10-day concomitant therapy, and 47% (252/535) in patients treated with 14-day triple therapy.

INTERPRETATION

Bismuth quadruple therapy is preferable to 14-day triple therapy in the first-line treatment in the face of rising prevalence of clarithromycin resistance. Concomitant therapy given for 10 days might not be optimum and a longer treatment length should be considered.

FUNDING

National Taiwan University Hospital and Ministry of Science and Technology of Taiwan.

Sequential therapy for 10 days versus triple therapy for 14 days in the eradication of Helicobacter pylori in the community and hospital populations: a randomised trial

OBJECTIVE

Significant heterogeneity was observed in previous trials that assessed the efficacies of sequential therapy for 10 days (S10) versus triple therapy for 14 days (T14) in the first-line treatment of Helicobacter pylori. We aimed to compare the efficacy of S10 and T14 and assess the factors affecting their efficacies.

DESIGN

We conducted this open-label randomised multicentre trial in eight hospitals and one community in Taiwan. 1300 adult subjects with H pylori infection naïve to treatment were randomised (1:1) to receive S10 (lansoprazole and amoxicillin for the first 5 days, followed by lansoprazole, clarithromycin and metronidazole for another 5 days) or T14 (lansoprazole, amoxicillin and clarithromycin for 14 days). All drugs were given twice daily. Successful eradication was defined as negative ¹³C-urea breath test at least 6 weeks after treatment. Our primary outcome was the eradication rate by intention-to-treat (ITT) and per-protocol (PP) analyses. Antibiotic resistance was determined by agar dilution test.

RESULTS

The eradication rates of S10 and T14 were 87.2% (567/650, 95% CI 84.4% to 89.6%) and 85.7% (557/650, 95% CI 82.8% to 88.2%) in the ITT analysis, respectively, and were 91.6% (556/607, 95% CI 89.1% to 93.4%) and 91.0% (548/602, 95% CI 88.5% to 93.1%) in the PP analysis, respectively. There were no differences in compliance or adverse effects. The eradication rates in strains susceptible and resistant to clarithromycin were 90.7% and 62.2%, respectively, for S10, and were 91.5% and 44.4%, respectively, for T14. The efficacy of T14, but not S10, was affected by CYP2C19 polymorphism.

CONCLUSIONS

S10 was not superior to T14 in areas with low clarithromycin resistance.

TRIAL REGISTRATION NUMBER

NCT01607918.

Mass Eradication of Helicobacter pylorito Prevent Gastric Cancer: Theoretical and Practical Considerations

Although the age-adjusted incidence of gastric cancer is declining, the absolute number of new cases of gastric cancer is increasing due to population growth and aging. An effective strategy is needed to prevent this deadly cancer. Among the available strategies, screen-and-treat for Helicobacter pylori infection appears to be the best approach to decrease cancer risk; however, implementation of this strategy on the population level requires a systematic approach. The program also must be integrated into national healthcare priorities to allow the limited resources to be most effectively allocated. Implementation will require adoption of an appropriate screening strategy, an efficient delivery system with a timely referral for a positive test, and standardized treatment regimens based on clinical efficacy, side effects, simplicity, duration, and cost. Within the population, there are subpopulations that vary in risk such that a "one size fits all" approach is unlikely to be ideal. Sensitivity analyses will be required to identify whether the programs can be utilized by heterogeneous populations and will likely require adjustments to accommodate the needs of subpopulations.

Downward trend in the prevalence of Helicobacter pylori infections and corresponding frequent upper gastrointestinal diseases profile changes in Southeastern China between 2003 and 2012

This present study aims to determine trends in the prevalence of H. pylori infections in Southeastern China between 2003 and 2012, and investigate corresponding changes in the prevalence of upper gastrointestinal diseases. This retrospective study screened 196,442 patients with a mean age of 47.49 ± 14.47 years (age range 5-100 years) in Southeastern China, and a total of 134,812 cases of an endoscopy-referral patient population with digestive symptoms between 2003 and 2012 were enrolled. Based on esophago-gastro-duodenoscopy and pathology, patients diagnosed with chronic gastritis, peptic ulcer, gastric cancer or reflux esophagitis were included in this study. Basic demographic and clinical characteristics such as H. pylori infection status and endoscopic findings were collected and analyzed. Among the 134,812 subjects, mean prevalence of H. pylori infection was 31.97 %; which demonstrated a linear downward trend from 42.40 to 23.82 % (P < 0.001) at an annual rate of 2 % from 2003 to 2012. Similarly, the prevalence of duodenal and gastric ulcer rapidly decreased from 12.65 to 6.57 % and from 7.51 to 3.78 %, respectively; while the prevalence of gastric cancer (from 3.76 to 2.34 %) did not significantly change in the same time period. In contrast, the prevalence of reflux esophagitis increased from 6.19 to 12.80 %. The progressively decreasing prevalence of H. pylori infections from 2003 to 2012 in Southeastern China appears to be linked with the decline of related upper gastrointestinal diseases and increase of some gastrointestinal motility diseases.

Gastric cancer: somatic genetics as a guide to therapy

Gastric cancer is the leading cause of cancer-related mortality across the world, with poor prognosis and a median overall survival of ≤12 months for advanced stage gastric cancer. Environmental, genetic and other predisposing factors contribute to the development of gastric cancer and a predominant factor was found to be infection of Helicobacter pylori Advances in understanding the deranged signalling pathways that are critical for normal cellular homeostasis helped in the development of novel drugs that target specific proteins and pathways to curtail the growth of gastric cancer. Genetic studies revealed several single nucleotide polymorphisms, chromosomal aberrations and epigenetic alterations that likely play a major role in elevating the susceptibility to develop gastric cancer. Methylation pattern of specific genes may likely prove to be a valid biomarker for early detection of gastric cancer, but much progress is needed to establish specific markers. Important developments have been made in targeting human epidermal growth factor receptor-2 and vascular endothelial growth factor receptor 2 for treating advanced gastro-oesophageal junction cancer, using specific monoclonal antibodies. Lack of efficacy with regard to targeting other signalling pathways including mesenchymal-epithelial transition/hepatocyte growth factor and mammalian target of rapamycin is probably due to suboptimal patient selection for these clinical trials, which is probably due to the lack of appropriate biomarkers, to decide on responsive patient population. Besides the development of antagonists for the cell growth-related signalling pathways, advances are also being made to tackle gastric cancer by immunotherapies, targeting immune check-points, which may hold promise for better treatment options in future.

Prevalence of upper gastrointestinal endoscopic findings in the community: A systematic review of studies in unselected samples of subjects

BACKGROUND AND AIM

Upper gastrointestinal endoscopic findings, such as esophagitis, Barrett's esophagus, peptic ulcer, and malignancy, represent a public health problem. This systematic review aimed to evaluate the prevalence of upper gastrointestinal endoscopic findings in the community.

METHODS

A systematic search was conducted in PUBMED and EMBASE to May 2015. Studies were eligible if they reported the prevalence of upper gastrointestinal endoscopic findings in unselected samples of the community.

RESULTS

Twelve articles were eligible, nine reported data from three endoscopic surveys (n = 3063 subjects), and three from national screening programs (n = 84 153). The overall prevalence of upper gastrointestinal endoscopic findings in the community was 30% in the Kalixanda study (Sweden), 24.9% in the Loiano-Monghidoro study (Italy), and 68.9% in the Systematic Investigation of Gastrointestinal Diseases study (China). The pooled prevalence of esophagitis, endoscopically suspected esophageal metaplasia (ESEM), peptic ulcer, and gastric cancer in all studies was 11.2, 5.1, 6.8, and 0.33%, respectively. The most frequent finding was esophagitis in Europe, with a prevalence of 15.5% in Sweden and 11.8% in Italy, and peptic ulcer in China (17.1%), both in asymptomatic and symptomatic individuals. The prevalence of Helicobacter pylori was positively associated with the prevalence of peptic ulcer (r = 0.91) but negatively associated with the prevalence of both esophagitis (r = -0.99) and ESEM (r = -0.95).

CONCLUSIONS

Upper gastrointestinal endoscopic findings are present in at least a quarter of subjects in the community with different patterns in Western and Eastern countries, both in asymptomatic and symptomatic subjects. H. pylori prevalence negatively impacts on the prevalence of reflux-related esophageal findings.

Asia-Pacific consensus on the management of gastro-oesophageal reflux disease: an update focusing on refractory reflux disease and Barrett's oesophagus

OBJECTIVE

Since the publication of the Asia-Pacific consensus on gastro-oesophageal reflux disease in 2008, there has been further scientific advancement in this field. This updated consensus focuses on proton pump inhibitor-refractory reflux disease and Barrett's oesophagus.

METHODS

A steering committee identified three areas to address: (1) burden of disease and diagnosis of reflux disease; (2) proton pump inhibitor-refractory reflux disease; (3) Barrett's oesophagus. Three working groups formulated draft statements with supporting evidence. Discussions were done via email before a final face-to-face discussion. We used a Delphi consensus process, with a 70% agreement threshold, using Grading of Recommendations Assessment, Development and Evaluation (GRADE) criteria to categorise the quality of evidence and strength of recommendations.

RESULTS

A total of 32 statements were proposed and 31 were accepted by consensus. A rise in the prevalence rates of gastro-oesophageal reflux disease in Asia was noted, with the majority being non-erosive reflux disease. Overweight and obesity contributed to the rise. Proton pump inhibitor-refractory reflux disease was recognised to be common. A distinction was made between refractory symptoms and refractory reflux disease, with clarification of the roles of endoscopy and functional testing summarised in two algorithms. The definition of Barrett's oesophagus was revised such that a minimum length of 1 cm was required and the presence of intestinal metaplasia no longer necessary. We recommended the use of standardised endoscopic reporting and advocated endoscopic therapy for confirmed dysplasia and early cancer.

CONCLUSIONS

These guidelines standardise the management of patients with refractory gastro-oesophageal reflux disease and Barrett's oesophagus in the Asia-Pacific region.

New advances in targeted gastric cancer treatment

Despite a decrease in incidence over past decades, gastric cancer remains a major global health problem. In the more recent period, survival has shown only minor improvement, despite significant advances in diagnostic techniques, surgical and chemotherapeutic approaches, the development of novel therapeutic agents and treatment by multidisciplinary teams. Because multiple genetic mutations, epigenetic alterations, and aberrant molecular signalling pathways are involved in the development of gastric cancers, recent research has attempted to determine the molecular heterogeneity responsible for the processes of carcinogenesis, spread and metastasis. Currently, some novel agents targeting a part of these dysfunctional molecular signalling pathways have already been integrated into the standard treatment of gastric cancer, whereas others remain in phases of investigation within clinical trials. It is essential to identify the unique molecular patterns of tumours and specific biomarkers to develop treatments targeted to the individual tumour behaviour. This review analyses the global impact of gastric cancer, as well as the role of Helicobacter pylori infection and the efficacy of bacterial eradication in preventing gastric cancer development. Furthermore, the paper discusses the currently available targeted treatments and future directions of research using promising novel classes of molecular agents for advanced tumours.

The Incidence of Gastric Adenocarcinoma Among Patients With Gastric Intestinal Metaplasia: A Long-term Cohort Study

BACKGROUND AND AIMS

Gastric intestinal metaplasia (IM) has been known as a premalignant condition, but estimates of its cancer risk vary widely. We aimed to analyze cancer risk of gastric IM by a long-term cohort study.

METHODS

We conducted a hospital-based study that included all patients with gastric IM between 1992 and 2010, and the development of gastric adenocarcinoma was evaluated until July 2011. Patients developing gastric cancer ≤180 days after the index diagnosis of IM were excluded. The incidence rate, the cumulative incidence, and the standardized incidence ratio (SIR) of gastric cancer were determined, and hazard ratios (HRs) of risk factors were calculated.

RESULTS

We identified 7059 patients with a median follow-up duration of 5.1 years, and 81 patients developed gastric adenocarcinoma during the study period. The 5-, 10-, and 15-year cumulative incidences of gastric cancer were 0.9% [95% confidence interval (CI), 0.6-1.1), 2.0% (95% CI, 1.5-2.6), and 3.0% (95% CI, 2.0-4.0), respectively. On multivariate analysis, older age (eg, 75 y and above; HR=7.4; 95% CI, 2.8-19.6), low-grade dysplasia (HR=4.0; 95% CI, 2.1-7.9), and high-grade dysplasia (HR=18.8; 95% CI, 9.0-39.5) were independent risk factors. As compared with the risk in the general population, the SIR of gastric cancer among patients with gastric IM was 2.5 (95% CI, 2.0-3.1). However, the SIR was only 2.0 (95% CI, 1.5-2.6) in the nondysplasia subgroup, but was up to 35.2 (95% CI, 15.2-69.4) in the high-grade dysplasia subgroup.

CONCLUSIONS

Gastric IM is an important risk factor for gastric cancer, but surveillance should be arranged only for those at an especially high risk.

Eradication of Helicobacter pylori and Gastric Cancer: A Systematic Review and Meta-analysis of Cohort Studies

BACKGROUND

Helicobacter pylori (H. pylori) is associated with an increased risk of gastric adenocarcinoma and gastric mucosa associated lymphoid tissue (MALT) lymphoma and a decreased risk of esophageal adenocarcinoma. We aimed to assess how eradication therapy for H. pylori influences the risk of developing these cancers.

METHODS

This was a systematic review and meta-analysis. We searched PubMed, Web of Science, Embase, and the Cochrane Library and selected articles that examined the risk of gastric cancer, MALT lymphoma, or esophageal cancer following eradication therapy, compared with a noneradicated control group.

RESULTS

Among 3629 articles that were considered, nine met the inclusion criteria. Of these, eight cohort studies assessed gastric cancer while one randomized trial assessed esophageal cancer. Out of 12 899 successfully eradicated patients, 119 (0.9%) developed gastric cancer, compared with 208 (1.1%) out of 18 654 noneradicated patients. The pooled relative risk of gastric cancer in all eight studies was 0.46 (95% confidence interval [CI] = 0.32 to 0.66, I(2) = 32.3%) favoring eradication therapy. The four studies adjusting for time of follow-up and confounders showed a relative risk of 0.46 (95% CI = 0.29 to 0.72, I(2) = 44.4%).

CONCLUSIONS

This systematic review and meta-analysis indicates that eradication therapy for H. pylori prevents gastric cancer. There was insufficient literature for meta-analysis of MALT lymphoma or esophageal cancer.

Gastric Cancer: How Can We Reduce the Incidence of this Disease?

Gastric cancer remains a prevalent disease worldwide with a poor prognosis. Helicobacter pylori plays a major role in gastric carcinogenesis. H. pylori colonization leads to chronic gastritis, which predisposes to atrophic gastritis, intestinal metaplasia, dysplasia, and eventually gastric cancer. Screening, treatment, and prevention of H. pylori colonization can reduce the incidence of gastric cancer. Other interventions that may yield a similar effect, although of smaller magnitude, include promotion of a healthy lifestyle including dietary measures, non-smoking, low alcohol intake, and sufficient physical activity. This chapter reviews interventions that can lead to a decline in gastric cancer incidence in high and low incidence countries.

Influence of Helicobacter pylori Infection on Metabolic Syndrome in Old Chinese People

Background. H. pylori infection is one of the most common chronic infectious inflammatory diseases worldwide and is also a risk factor for atherosclerosis. Patients with metabolic syndrome are known to be at increased risk for atherosclerosis. The aim of our study was to assess the effects of H. pylori infection on serum lipids, body mass index (BMI), and metabolic syndrome in old Chinese people. Material and Method. A total of 191 (133 males and 58 females, aged 73.19 ± 11.03 years) people who had gastroscopy examination in our hospital were divided into H. pylori-positive group (n = 80) and H. pylori-negative group (n = 111). H. pylori infection was diagnosed by rapid urease test. Results. Patients with H. pylori infection had higher BMI and fasting glucose levels and incidence of metabolic syndrome (p < 0.01). It was found that BMI (p < 0.01, OR 74.469), H. pylori infection (p < 0.01, OR 5.427), total cholesterol (p < 0.01, OR 15.544), and diabetes mellitus (p < 0.01, OR 23.957) were significantly associated with the risk of metabolic syndrome by binary logistic regression analysis. Conclusions. Patients with H. pylori infection had higher BMI and fasting glucose levels and had incidence of metabolic syndrome.

Strategies for Prevention of Gastric Cancer: Progress from Mass Eradication Trials

BACKGROUND

Helicobacter pylori infection is the cause of the majority of gastric cancer. Meta-analyses on several interventional trials, irrespective of the target population, unanimously demonstrated the benefit of eradication therapy in reducing the occurrence of gastric cancer. Based on the evidence for the preventive effects on gastric cancer by eradication therapy in the general population, the International Agency for Research on Cancer advocated eradication of H. pylori as the primary preventive strategy for gastric cancer. Consensus reports on H. pylori gastritis by experts also recommended eradication of H. pylori as the strategy for prevention of gastric cancer.

KEY MESSAGES

H. pylori is responsible for the majority of gastric cancer. As the eradication of the infection has been shown to reduce subsequent development of gastric cancer, a number of large-scale controlled trials involving a large number of subjects are currently underway in various countries to further verify the feasibility and effects of H. pylori eradication on gastric cancer prevention. However, such studies might be considered unethical as we already knew that the criminal role of H. pylori in gastric carcinogenesis. In Japan, rather than conducting clinical trials, the government adopted insurance coverage for H. pylori gastritis irrespective of symptoms. This policy brought about a massive surge in eradication therapy, which will ensue in a drastic reduction in the prevalence of H. pylori by 2030 as well as gastric cancer.

CONCLUSIONS

Primary prevention of gastric cancer is now moving into implementation phase in Japan and will be spreading in other counties where long-term clinical trials have started.

CXC chemokine CXCL12 tissue expression and circulating levels in peptic ulcer patients with Helicobacter pylori infection

Helicobacter pylori (H. pylori) infection is among the most prevalent human infections. CXCL12 is a well-known CXC chemokine involved in inflammation and play major roles in angiogenesis. There is currently very limited data on the role of CXCL12 in peptic ulcer disease. Hence, we aimed to explore whether CXCL12 is involved in the pathogenesis of peptic ulcer induced by H. pylori. In this study, we enrolled 102 H. pylori-infected patients, including 51 with active ulcer (GA) and 51 with healing ulcer (GH). We also recruited 50 healthy subjects as control, which did not show any sign or symptoms of chronic inflammatory diseases, infection, or immune-related disorders. Endoscopy was performed to determine the stage of the disease. ELISA was used for detection of H. pylori infection and CXCL12 measurement. We also employed western blotting to detect CXCL12 in ulcerative lesions of H. pylori. Demographic data were also collected by questionnaire. Our results demonstrated that CXCL12 serum levels in GA group (151.8±18.31pg/mL) were significantly higher than those in GH (36.89±6.78pg/mL) and control groups (33.77±9.12pg/mL) (P<0.0001). However, we did not observe a significant difference between GH and control groups. Moreover, overexpression of CXCL12 in gastric lesions of patients in GA group was confirmed by Western blot analysis. According to the result of the present study, it could be concluded that CXCL12 is involved in the pathogenesis and healing of H. pylori-induced peptic ulcer. CXCL12 serum levels may also be used to distinguish between GA and GH phases of the disease.

Gastric adenocarcinoma: the role of Helicobacter pylori in pathogenesis and prevention efforts

Gastric cancer is the third most common cause of cancer deaths in the world, prompting high-risk countries like South Korea and Japan to establish nationwide screening programmes. Helicobacter pylori is linked to the majority of gastric adenocarcinoma cases and to the vast majority of non-cardia gastric adenocarcinomas. Several studies have demonstrated the effectiveness of 'test-and-treat' programmes for H. pylori infection to prevent gastric cancer in high-risk populations. While this strategy has gained momentum, providers in low-risk developed countries may be unaware of the risk individual patients face, particularly those who have emigrated from high-risk regions and members of economically disadvantaged minority groups. Rapidly evolving science in recent years has made it difficult for clinicians to keep up with the current best practices. This article reviews the epidemiology of H. pylori and gastric cancer, screening and diagnostic tests and the current treatment regimens for clinicians.

Recurrence of Helicobacter pylori infection after successful eradication

Helicobacter pylori (H. pylori) is a gram-negative, micro-aerobic bacterium that lives in the stomach and duodenum. Infection with H. pylori would cause some diseases such as peptic ulcer disease and gastric cancer. Some H. pylori associated gastric diseases could be prevented by the eradication of H. pylori. However, some people develop recurrence after successful H. pylori eradication. Many factors affect the recurrence such as human development index, treatment for the whole family, standard treatment combined with supragingival scaling, and iatrogenic transmission. This article reviews the recurrence of H. pylori infection after successful treatment.

Association Between Helicobacter pylori Eradication and Gastric Cancer Incidence: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

Eradication of Helicobacter pylori infection has been reported to reduce the risk of gastric cancer among asymptomatic individuals in high-risk areas. The magnitude of benefit of H pylori eradication in populations with different levels of gastric cancer risk and in different clinical scenarios is unclear. We performed a systematic review and meta-analysis of randomized controlled trials and observational studies to investigate the effects of H pylori eradication on the incidence of gastric cancer.

METHODS

We searched PubMed, Cochrane Library, and ClinicalTrials.gov, reviewing titles and abstracts of studies of the effects of eradication of H pylori infection on risk of gastric cancer, through May 2015. We also searched bibliographies of included studies, related reviews, and abstracts presented at Digestive Disease Week. Twenty-four eligible studies (22 research manuscripts and 2 abstracts) were included in our meta-analysis (715 incident gastric cancers among a total of 48,064 individuals/340,255 person-years). We assessed the effects, as well as their modification by baseline gastric cancer incidence, study design (randomized trial vs observational study), clinical scenario (asymptomatic infected individuals vs individuals after endoscopic resection of early gastric cancer), demographic characteristics of patients (age and sex), and duration of follow-up.

RESULTS

After adjustment for baseline gastric cancer incidence, individuals with eradication of H pylori infection had a lower incidence of gastric cancer than those who did not receive eradication therapy (pooled incidence rate ratio = 0.53; 95% confidence interval: 0.44-0.64). There was little heterogeneity among studies. Baseline gastric cancer incidence modified the benefit of H pylori eradication (P = .037 for interaction); the incidence rate ratio of gastric cancer decreased in a nonlinear fashion with increasing baseline incidence of gastric cancer (P = .018, in comparison with the linear model). The benefit also modestly increased with age (P = .023 for interaction), but this might be due to correlation between age and baseline gastric cancer incidence. Eradication provided significant benefit for asymptomatic infected individuals (pooled incidence rate ratio, 0.62; 95% CI: 0.49-0.79) and individuals after endoscopic resection of gastric cancers (pooled incidence rate ratio, 0.46; 95% CI: 0.35-0.60). The benefits of H pylori eradication did not differ with study design, sex, or follow-up period.

CONCLUSIONS

In a systematic review and meta-analysis, we associated eradication of H pylori infection with a reduced incidence of gastric cancer. The benefits of eradication vary with baseline gastric cancer incidence, but apply to all levels of baseline risk.

Interaction between inflammatory mediators and miRNAs in Helicobacter pylori infection

Helicobacter pylori cause chronic inflammation favouring gastric carcinogenesis, and its eradication may prevent malignant transformation. We evaluated whether H. pylori infection and its eradication modify the expression of inflammatory mediators in patients with chronic gastritis. Furthermore, we assessed whether microRNAs modulate inflammatory pathways induced by H. pylori and identified miRNA–gene interaction networks. mRNA and protein expression of TNFA, IL6, IL1B, IL12A, IL2 and TGFBRII and miRNAs miR‐103a‐3p, miR‐181c‐5p, miR‐370‐3p, miR‐375 and miR‐223‐3p were evaluated in tissue samples from 20 patients with chronic gastritis H. pylori negative (Hp−) and 31 H. pylori positive (Hp+), before and three months after bacterium eradication therapy, in comparison with a pool of Hp− normal gastric mucosa. Our results showed that H. pylori infection leads to up‐regulation of TNFA, IL6, IL12A and IL2 and down‐regulation of miRNAs. Bacterium eradication reduces the expression of TNFA and IL6 and up‐regulates TGFBRII and all investigated miRNAs, except miR‐223‐3p. Moreover, transcriptional profiles of inflammatory mediators and miRNAs after eradication are different from the non‐infected group. Deregulated miRNA–mRNA interaction networks were observed in the Hp+ group before and after eradication. Therefore, miRNAs modulated cytokine expression in the presence of H. pylori and after its eradication, suggesting that miRNAs participate in the pathological process triggered by H. pylori in the gastric mucosa.

Stage-specific Dietary Factors Associated with the Correa Multistep and Multifactorial Process of Human Gastric Carcinogenesis

We assessed how individual dietary intakes act at different points in the chain of sequential stage of the Correa model in an area of Taiwan with high incidence of gastric cancer (GC). Using data on 2,201 participants in a two-stage screening for gastric neoplasia with pepsinogen test, we identified 154 superficial gastritis (SG), 32 atrophic gastritis (AG), 117 intestinal metaplasia (IM), and 22 GC. Effects of individual item-based and construct-based dietary variables aggregated by factor analysis on each stage of gastric neoplasm were assessed. Based on 1,211 subjects with complete information on serological test and dietary questionnaire, SG was associated with positive quartile trend for the intake of meat (trend test P = 0.0014) and the intake of fruits and leafy vegetables (trend test P = 0.0177), but with the negative trend for the intake of shrimp sauce (trend test P = 0.039). A significant positive association was noted between milk and AG (trend test P = 0.014) and IM (P = 0.0087). A positive association between seafood and IM was noted (P = 0.011). Frequent leafy vegetable intake based on individual item was inversely associated with GC (P = 0.0084), whereas frequent intake of meat showed a high positive association (P<0.001). Stage-specific dietary factors underpinning the Correa model were identified.

Risk factors for gastric intestinal metaplasia

Gastric intestinal metaplasia is the most common precancerous lesion of gastric cancer. Due to the unsatisfying treatment efficacy for gastric cancer especially advanced gastric cancer, the key steps of prevention and treatment of gastric cancer are lowering the incidence and improving the early diagnosis. Therefore, it is very important to clarify the risk factors associated with gastric cancer and its precancerous lesion for first-line prevention of gastric cancer. Accumulated evidence indicates that the development of gastric intestinal metaplasia is closely related to Helicobacter pylori infection, age, sex, family history of gastric cancer, smoking, high salt diet, bile acid reflux and so on. This review mainly focuses these factors associated with gastric intestinal metaplasia.

Helicobacter pylori chronic gastritis updated Sydney grading in relation to endoscopic findings and H. pylori IgG antibody: diagnostic methods

Helicobacter pylori (Hp) inhabits the stomach of > 50% of humans and has been established as a major etiological factor in the pathogenesis of chronic gastritis, gastric atrophy, peptic ulcer disease, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. The aim of this study was to provide unequivocal information about Hp-associated gastritis grading according to the Sydney grading system and to compare the histopathological features with the endoscopic findings and anti-Hp immunoglobulin (Ig)G serological status. This analytical study was conducted on 157 patients with dyspeptic gastritis. All patients underwent esophagogastroduodenoscopy, and antrum and corpus biopsies were taken. Blood samples were obtained from all participants. Different stains were performed on formalin-fixed, paraffin-embedded tissue blocks that included hematoxylin and eosin and Giemsa stain for histopathological interpretation. The endoscopic findings of gastritis were observed in 120 patients and most of them showed hyperemia (80 patients), whereas seven patients had normal appearing gastric mucosa. Histologically variable numbers of mononuclear inflammatory cellular infiltrates were seen in 150 cases (95.5%). Most of them showed Grade 1 gastritis (80 patients), whereas Grades 2 and 3 were found in 43 and 27 biopsies, respectively. Hp colonization was observed in most of the examined biopsies (93.7%). Hp-IgG seropositivity was found in 80.9% of cases and 19.1% were seronegative. The relationship between endoscopic and histological findings was significant (p < 0.001).