Systematic review: Helicobacter pylori eradication for the prevention of gastric cancer

Cost-effectiveness analysis of different screening strategies for helicobacter pylori infection in Iran: A model-based evaluation

BACKGROUND

The World Health Organization recommends assessing screening for helicobacter pylori infection to lower gastric cancer (GC) rates. Therefore, we carried out a study to evaluate the cost-effectiveness of different H. pylori screening approaches in Iran.

MATERIALS AND METHODS

We used a Markov model with a 50-year time horizon and health system perspective to compare four H. pylori screening strategies (endoscopy, serology, urea breath test [UBT], stool antigen test [SAT]) to no screening in the population aged 20 years and older in Iran. Model parameters were extracted from primary data and published studies. Cost data also came from medical records of 120 patients at different stages of GC. We calculated costs, quality-adjusted life years (QALYs), and incremental cost-effectiveness ratios (ICERs) for each strategy. Probabilistic sensitivity analysis (PSA) using Monte Carlo simulation tested the model's robustness. All analyses were done in TreeAge Pro 2020.

RESULTS

All screening strategies provided more QALYs compared to no screening. Base-case analysis found the UBT strategy was the most cost-effective, with an ICER of 101,106,261.5 Iranian rial (IRR) per QALY gained, despite being more costly. No screening and endoscopy were dominated strategies, meaning they had higher costs but provided fewer effectiveness compared to other options. PSA showed at a willingness-to-pay (WTP) threshold of 316,112,349 IRR (Iran's GDP per capita) per QALY, UBT was the optimal strategy in 57.1% of iterations.

CONCLUSION

This cost-effectiveness analysis found that screening for H. pylori may be cost-effective in Iran. Among the 4 screening strategies examined, UBT was the most cost-effective approach. Further studies should do cost-effectiveness analyses for specific age groups to optimize the benefits achieved with limited resources.

Spatial Clusters of Cancer Mortality in Brazil: A Machine Learning Modeling Approach

Objectives: Our aim was to test if machine learning algorithms can predict cancer mortality (CM) at an ecological level and use these results to identify statistically significant spatial clusters of excess cancer mortality (eCM). Methods: Age-standardized CM was extracted from the official databases of Brazil. Predictive features included sociodemographic and health coverage variables. Machine learning algorithms were selected and trained with 70% of the data, and the performance was tested with the remaining 30%. Clusters of eCM were identified using SatScan. Additionally, separate analyses were performed for the 10 most frequent cancer types. Results: The gradient boosting trees algorithm presented the highest coefficient of determination (R 2 = 0.66). For total cancer, all algorithms overlapped in the region of Bagé (27% eCM). For esophageal cancer, all algorithms overlapped in west Rio Grande do Sul (48%-96% eCM). The most significant cluster for stomach cancer was in Macapá (82% eCM). The most important variables were the percentage of the white population and residents with computers. Conclusion: We found consistent and well-defined geographic regions in Brazil with significantly higher than expected cancer mortality.

Network meta-analysis of different dosages of esomeprazole and rabeprazole for the treatment of Helicobacter pylori

BACKGROUND

The optimal dosage of new generation proton pump inhibitors (PPIs) in increasing cure rate of Helicobacter pylori (H. pylori) infection remains unclear. This network meta-analysis aimed to comprehensively evaluate the comparative efficacy and safety of different dosages of esomeprazole and rabeprazole in treating H. pylori infection.

MATERIALS AND METHODS

We searched PubMed, Cochrane Central Registry for Controlled Trials (CENTRAL), and EMBASE for randomized controlled trials (RCTs) involving esomeprazole and rabeprazole with different dosages from their inception through 31 March, 2022. After data extraction and risk of bias assessment, network meta-analyses were conducted using STATA 14.0. We calculated the surface under the cumulative ranking (SUCRA) to rank all regimens.

RESULTS

Thirteen studies including 14 reports were included. Six dosages including rabeprazole 10 mg (R10bid), 20 mg (R20bid), and 40 mg (R40bid) twice daily and esomeprazole 20 mg (E20bid) and 40 mg (E40bid) twice daily as well as 40 mg once daily (E40qd) were identified. Network meta-analysis suggested that R40bid ranked highest in the cure rate (83.8%), followed by E40bid (82.6%), E20bid (54.5%), R20bid (34.2%), R10bid (22.8%), and E40qd (22.0%); however, E40qd ranked highest in adverse events (91.1%), followed by R20bid (57.8), R10bid (57.6%), E20bid (38.9%), E40bid (34.2%), and R40bid (20.4%). Sensitivity analyses confirmed the robustness of these results.

CONCLUSIONS

Based on the available evidence, R40bid and E40bid might be the optimum dosage to increase the cure rate; however, E40qd was superior for adverse events. Nevertheless, future studies should validate the results from this network meta-analysis.

Risk factors for gastric cancer in patients with Lynch syndrome

INTRODUCTION

The cumulative lifetime risk of gastric cancer (GC) in patients with Lynch syndrome (LS) is reported to be 8%. There is limited evidence on specific risk factors for GC and no agreement among guidelines on gastric endoscopic surveillance schedule in LS patients.

AIMS AND METHODS

We conducted a retrospective cohort study to identify risk factors for gastric precancerous conditions (chronic atrophic gastritis and intestinal metaplasia) and GC in patients with LS and a case-control study to compare the prevalence of these conditions with a control group.

RESULTS

We included 385 LS patients (40.5% male, mean age 49.0 years). During a median follow-up period of 48 months (interquartile range, 24-84 months), precancerous conditions were identified in 110 patients (34%) and the prevalence of advanced stages of atrophic gastritis was 3% for OLGA III/IV and 0.6% OLGIM III/IV. Family history of GC was significantly associated with OLGA III/IV ( P = 0.020). Among LS patients, 10 patients (2.6%) were diagnosed with GC (incidence rate of 5/1000 persons-year). Older age and OLGA III/IV were identified as risk factors for GC ( P < 0.001). When compared with controls, patients with LS had significantly higher rates of Hp infection ( P = 0.035) and lower OLGA and OLGIM stages ( P < 0.001 and P = 0.026, respectively).

CONCLUSION

In our cohort, the incidence of GC and advanced stages of atrophic gastritis was low. Older age and OLGA III/IV were associated with a higher risk of GC. Identification of risk factors for GC in LS patients can help tailoring endoscopic surveillance.

Levofloxacin-based therapy as an efficient alternative for eradicating Helicobacter pylori infection in Iran: a systematic review and meta-analysis

OBJECTIVES

Despite excessive resistance of Helicobacter pylori to clarithromycin among Iranian population, unfortunately, clarithromycin-based therapy is still prescribed in Iran. Recent studies have shown high rates of H. pylori eradication in patients treated with levofloxacin. The main purpose of this study was to compare the effect of levofloxacin with clarithromycin on the eradication of H. pylori infection in Iranian population.

METHODS

A comprehensive meta-analysis was done for the relevant cohort studies and clinical trials to compare the therapeutic effects of levofloxacin with clarithromycin in Iranian population. We pooled the data using odds ratio corresponding to 95% confidence intervals to find the clinical efficacy of levofloxacin versus clarithromycin to treat H. pylori infection. The heterogeneity and publication bias were also measured for the included studies.

RESULTS

A total of 13 studies were included in the quantitative synthesis. Eradication rate in patients receiving levofloxacin and clarithromycin were 75% and 66.3%, respectively (OR: 1.76; 95% CI: 1.40-2.20). In addition, in the subgroup analysis, it was confirmed that cure rate is relatively higher in levofloxacin-treated cases. However, there is significant heterogeneity as well as publication bias, thus, the results need to be interpreted with caution.

CONCLUSIONS

We found that the success of levofloxacin treatment was significantly higher than that of clarithromycin. Therefore, it is suggested that clarithromycin-based triple therapy be replaced by levofloxacin-based triple therapy in countries with high resistance rate to clarithromycin such as Iran. Nevertheless, findings of the present study need to be approved with larger investigation on Iranian population.

Cost-Effectiveness of Screening Helicobacter pylori for Gastric Cancer Prevention: a Systematic Review

Globally, prevalence of Helicobacter pylori is around 50%, and it has a directly proportional relationship with gastric cancer. Screening and treatment of Helicobacter pylori could reduce gastric cancer by 35%. Drawing on the scarce resources, it is reasonable to use the most cost-effectiveness Helicobacter pylori screening procedure. The purpose of this study was to evaluate Helicobacter pylori screening techniques and to specify the efficient technique from a cost-effectiveness perspective. This systematic review was conducted via searching electronic databases including Scopus, Embase, PubMed, Web of Science, and Cochrane Reviews. Our search retrieved 904 articles, of which, 606 full-text studies have been selected after duplicate removal. Next, the 25 articles were sorted based on eligibility criteria and quality appraisal; eventually, only eight studies have been included for analysis. We reported the incremental cost-effectiveness ratio (ICER) screening compared to non-screening and different screening strategies. Eight studies were identified and retained for the final analysis. In this study, when screening techniques were compared to no-screening, serology screening techniques showed to be cost-effective. The lowest ICER calculated was US$$1230 cost per life-year gained (LYG) and US$1500 cost per quality-adjusted life-year (QALY). However, determining the optimal strategy compared to other strategies was depended on parameters such as context-specific, type of cost, threshold, and perspective, and also, it influenced by the framework of the cost-effectiveness analysis.

Endoscopy to Diagnose and Prevent Digestive Cancers in Lynch Syndrome

Lynch syndrome patients could benefit from various recommendations to prevent digestive cancers. In this review, we summarize the criteria to identify Lynch syndrome in patients with digestive cancers. We detail endoscopic screening procedures in patients with Lynch syndrome for gastric, small bowel, pancreatic, and colorectal cancers. We review the precise modalities of endoscopic follow-up, particularly the discrepancies that exist between the guidelines of the various scientific societies. We discuss the treatment of colorectal cancers in Lynch syndrome cases and patient adherence to endoscopic follow-up programs.

In Vitro Framework to Assess the Anti-Helicobacter pylori Potential of Lactic Acid Bacteria Secretions as Alternatives to Antibiotics

Helicobacter pylori is a prevalent bacterium that can cause gastric ulcers and cancers. Lactic acid bacteria (LAB) ameliorate treatment outcomes against H. pylori, suggesting that they could be a source of bioactive molecules usable as alternatives to current antibiotics for which resistance is mounting. We developed an in vitro framework to compare the anti-H. pylori properties of 25 LAB and their secretions against H. pylori. All studies were done at acidic and neutralized pH, with or without urea to mimic various gastric compartments. Eighteen LAB strains secreted molecules that curtailed the growth of H. pylori and the activity was urea-resistant in five LAB. Several LAB supernatants also reduced the urease activity of H. pylori. Pre-treatment of H. pylori with acidic LAB supernatants abrogated its flagella-mediated motility and decreased its ability to elicit pro-inflammatory IL-8 cytokine from human gastric cells, without reverting the H. pylori-induced repression of other pro-inflammatory cytokines. This study identified the LAB that have the most anti-H. pylori effects, decreasing its viability, its production of virulence factors, its motility and/or its ability to elicit pro-inflammatory IL-8 from gastric cells. Once identified, these molecules can be used as alternatives or complements to current antibiotics to fight H. pylori infections.

Incidence of metachronous gastric cancer after endoscopic submucosal dissection associated with eradication status of Helicobacter pylori

OBJECTIVE

This study compared the clinicopathological features and treatment outcomes of patients with primary early gastric cancers (EGCs) who had undergone Helicobacter pylori eradication and endoscopic submucosal dissection (ESD) with those of patients who were H. pylori-positive and had undergone ESD. Additionally, we investigated the incidence of metachronous cancer in these patients.

METHODS

We retrospectively analyzed 1849 EGCs in 1407 patients who underwent ESD whom 201 primary EGCs were detected after H. pylori eradication (eradication group) and 1648 primary EGCs were detected in patients infected with H. pylori (infection group). We evaluated the clinicopathological features and treatment outcomes of the first ESD. We next divided 938 patients whose follow-up periods were >1 year into three groups, an eradication group (n = 61), an infection group (n = 562), and an eradication after ESD group (n = 315). The groups' cumulative metachronous occurrence rates were determined.

RESULTS

The eradication group's median tumor size was significantly smaller, and the tumors were significantly more likely to be flat/depressed than those in the infection group. The groups did not differ regarding the treatment outcomes. The cumulative incidence of metachronous cancer was significantly higher in the eradication group than in the eradication after ESD group (P = 0.0454) and in the infection group than in the eradication after ESD group (P = 0.0233).

CONCLUSION

The treatment outcomes for EGC in the eradication group were favorable. The higher incidence of metachronous cancer in the eradication group suggests that careful endoscopic follow-up examinations are required.

Does Helicobacter pylori Eradication Reduce the Incidence of Metachronous Gastric Cancer After Curative Endoscopic Resection of Early Gastric Cancer: A Systematic Review and Meta-Analysis

BACKGROUND

Whether Helicobacter pylori eradication could reduce the risk of metachronous gastric cancer remain controversial. In the present study, we performed a systematic review and meta-analysis to evaluate the preventive effect of H. pylori eradication on the occurrence of metachronous gastric cancer after curative endoscopic resection of early gastric cancer.

METHODS

The related studies were identified by searching PubMed and Embase databases. According to the H. pylori infection status and subsequent treatment, all patients were classified into H. pylori negative group, H. pylori eradication group and noneradication group. The relevant data were extracted and pooled effect size was assessed using a fixed effect model or a random effect model.

RESULTS

A total of 11 retrospective cohort studies and 3 randomized controlled trials were included in this meta-analysis. The results based on the cohort studies indicated that the risk of metachronous gastric cancer was significantly lower in H. pylori eradication group than in noneradication group (hazard ratios: 0.65, 95% confidence interval: 0.50-0.86, P=0.002; I=0%). The pooled result of 2 randomized controlled trials demonstrated that the patients receiving anti-H. pylori treatment had a lower risk of metachronous gastric cancer than those who did not receive H. pylori eradication treatment (hazard ratios: 0.43, 95% confidence interval: 0.26-0.70, P=0.001; I=0%). In addition, the occurrence of metachronous gastric cancer in H. pylori eradication group was not significantly different from that in H. pylori negative group.

CONCLUSIONS

Successful H. pylori eradication may be useful for the prevention of metachronous gastric cancer after curative endoscopic resection of early gastric cancer. Thus, anti-H. pylori treatment should be considered for those patients with H. pylori infection after curative endoscopic resection.

Influence of N-acylhomoserine lactonase silver nanoparticles on the quorum sensing system of Helicobacter pylori: A potential strategy to combat biofilm formation

The treatment of Helicobacter pylori usually fails due to their ability to form biofilms and resistance to antibiotics. This might potentially lead to gastric carcinoma and mucosa-associated lymphoid tissue lymphoma. In the present study, we elucidate the potential role of N-acylhomoserine lactonase stabilized silver nanoparticles (AiiA-AgNPs) in treating biofilms produced by H. pylori. AiiA-AgNPs inhibited quorum sensing (QS) by degradation of QS molecules, thereby reducing biofilm formation, urease production, and altering cell surface hydrophobicity of H. pylori. AiiA-AgNPs showed no cytotoxic effects on RAW 264.7 macrophages at the effective concentration (1-5 µM) of antibiofilm activity. In addition, AiiA-AgNP in high concentration (80-100 µM) exhibited cytotoxicity against HCT-15 carcinoma cells, depicting its therapeutic role in treating cancer.

Cost-effectiveness analysis and effectiveness of pharmacist-managed outpatient clinics in Helicobacter pylori eradication therapy

BACKGROUND

Helicobacter pylori is involved in many upper gastrointestinal diseases such as peptic ulcers and gastric cancers. In this study, we compared the cost-effectiveness of lansoprazole and vonoprazan in H. pylori eradication therapy and examined the effectiveness of pharmacist-managed outpatient clinics.

METHODS

We investigated the efficacy and cost-effectiveness of pharmacist-managed outpatient clinics in H. pylori eradication therapy at our hospital from January 2015 to December 2017. The subjects were classified into three groups: lansoprazole group; vonoprazan group; and the medication instruction group, which received instructions at the pharmacist-managed outpatient clinics (intervention group). We examined the eradication rate and cost-effectiveness ratio of each group.

RESULTS

The eradication rate of primary eradication therapy was 75.2% in the lansoprazole group, 87.8% in the vonoprazan group and 91.4% in the intervention group. When mental component summary was used as quality of life score, cost-effectiveness ratio was 224.7 yen in lansoprazole group, 223.9 yen in vonoprazan group and 222.2 yen in intervention group. Setting up pharmacist-managed outpatient clinics increases the pharmacist labour cost necessary for eradication therapy. However, if the medication instructions provided by the pharmacist can lead to improved disinfection efficiency, improvement in cost efficiency can be expected.

CONCLUSION

Although medication instructions provided at the pharmacist-managed outpatient clinics incur additional labour costs, they improve patient quality of life as well as disinfection rate in H. pylori eradication therapy. Therefore, pharmacist-managed outpatient clinics are useful from the viewpoint of pharmacoeconomics.

Short-term detection of gastric genotoxicity using the DNA double-strand break marker γ-H2AX

DNA damage caused by Helicobacter pylori infection and chronic inflammation or exposure to genotoxic agents is considered an important risk factor of gastric carcinogenesis. In this study, we have evaluated a short-term technique to detect DNA damage response to various chemical carcinogens; it involves visualization of Ser 139-phosphorylated histone H2AX (γ-H2AX) foci by immunohistochemistry and expression analysis of other genes by quantitative RT-PCR. Six-week-old male rats were intragastrically administered N-methyl-N-nitrosourea (MNU), 3,2'-dimethyl-4-aminobiphenyl (DMAB), dimethylnitrosamine (DMN), and 1,2- dimethylhydrazine (DMH) for 5 days/week for 4 weeks, using corn oil as a vehicle. Animals were sacrificed at day 28, and their stomachs were excised. γ-H2AX foci formation, indicating DNA double-strand breaks, was observed in the proliferative zone of both fundic and pyloric glands. The number of positive cells per gland was significantly high in pyloric glands in the MNU group and in fundic glands in the MNU and DMAB groups. A significant increase in p21waf1 mRNA level was observed in the DMN group compared with the control, which was in contrast to the decreasing tendency of the h2afx mRNA level in the MNU and DMN groups. Apoptotic cells positive for γ-H2AX pan or peripheral nuclear staining were observed on the surface layer of the fundic mucosa in the MNU group. The fundic pepsinogen a5 (pga5) mRNA level showed a significant decrease, indicating gland damage. The pyloric pepsinogen c mRNA level showed no change. In conclusion, γ-H2AX in combination with other gene expression analyses could be a useful biomarker in a short-term experiment on gastric chemical genotoxicity.

Long-Term Effects of Helicobacter pylori Eradication on Metachronous Gastric Cancer Development

Background/Aims

Gastric mucosal atrophy and intestinal metaplasia due to Helicobacter pylori infection are the main precursor lesions of gastric cancer. The aim of this study was to evaluate the long-term effects of H. pylori eradication on the progression of precancerous lesions to metachronous cancer after endoscopic resection of early gastric cancer (EGC).

Methods

Patients who underwent endoscopic resection of EGC were retrospectively reviewed. Changes in precancerous lesions and development of metachronous cancer were compared according to H. pylori eradication and final infection status.

Results

In total, 565 patients were followed for over 5 years after endoscopic resection of EGC. The grade of atrophy on corpus was significantly lower in the H. pylori-eradicated group than in the persistent group during follow-up (p=0.029). In patients ＜70 years of age, the cumulative incidence rate of metachronous cancer was significantly lower in the H. pylori-eradicated group than in the persistent group (p=0.018). Age was an independent risk factor for metachronous cancer development.

Conclusions

H. pylori eradication might prevent the development of metachronous cancer in patients ＜70 years of age by delaying the progression of precancerous lesions after endoscopic resection of EGC.

Global estimate of gastric cancer in Helicobacter pylori-infected population: A systematic review and meta-analysis

There is information regarding the rates of gastric cancer (GC) in different populations and the important role of Helicobacter pylori in GC development; however, no comprehensive study has yet been performed to investigate the prevalence of GC in H. pylori-infected patients. PubMed, Embase, and Cochrane Library through January 1, 2000 were searched without language restrictions. Quality of included studies was assessed with a critical appraisal checklist recommended by the Joanna Briggs Institute. All of the analyses were conducted using Comprehensive Meta-Analysis Software Version 2.0 and Stata 14.0. Forty-four studies from 17 countries were included. The pooled frequency of GC was 17.4% (95% confidence interval: 16.4-18.5) in H. pylori-infected population. The frequency of GC among H. pylori-infected population varied markedly across countries. The highest rate of GC was observed in H. pylori-infected individuals from Asian countries. The frequency of GC was relatively high in H. pylori-infected population in the world. However, the eradication of H. pylori might be a promising strategy for GC prevention, especially in high-risk populations such as Asian countries.

SNP-SNP interactions of three new pri-miRNAs with the target gene PGC and multidimensional analysis of H. pylori in the gastric cancer/atrophic gastritis risk in a Chinese population

Gastric cancer (GC) is a multistep complex disease involving multiple genes, and gene–gene interactions have a greater effect than a single gene in determining cancer susceptibility. This study aimed to explore the interaction of the let-7e rs8111742, miR-365b rs121224, and miR-4795 rs1002765 single nucleotide polymorphisms (SNPs) with SNPs of the predicted target gene PGC and Helicobacter pylori status in GC and atrophic gastritis (AG) risk. Three miRNA SNPs and seven PGC SNPs were detected in 2448 cases using the Sequenom MassArray platform. Two pairwise combinations of miRNA and PGC SNPs were associated with increased AG risk (let-7e rs8111742 – PGC rs6458238 and miR-4795 rs1002765 – PGC rs9471643). Singly, miR-365b rs121224 and PGC rs6912200 had no effect individually but in combination they demonstrated an epistatic interaction associated with AG risk. Similarly, let-7e rs8111742 and miR-4795 rs1002765 SNPs interacted with H. pylori infection to increase GC risk (rs8111742: P_interaction = 0.024; rs1002765: P_interaction = 0.031, respectively). A three-dimensional interaction analysis found miR-4795 rs1002765, PGC rs9471643, and H. pylori infection positively interacted to increase AG risk (P_{interaction =} 0.027). Also, let-7e rs8111742, PGC rs6458238, and H. pylori infection positively interacted to increase GC risk (P_{interaction =} 0.036). Furthermore, both of these three-dimensional interactions had a dosage–effect correspondence (P_trend < 0.001) and were verified by MDR. In conclusion, the miRNAs SNPs (let-7e rs8111742 and miR-4795 rs1002765) might have more superior efficiency when combined with PGC SNPs and/or H. pylori for GC or AG risk than a single SNP on its own.

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.

What is the quantitative risk of gastric cancer in the first-degree relatives of patients? A meta-analysis

AIM

To quantify the risk of gastric cancer in first-degree relatives of patients with the cancer.

METHODS

A comprehensive literature search was performed. Case-control trials comparing the frequency of a positive family history of gastric cancer in patients with gastric cancer, vs non-gastric cancer controls were retrieved. Studies with missed or non-extractable data, studies in children, abstracts, and duplicate publications were excluded. A meta-analysis of pooled odd ratios was performed using Review Manager 5.0.25. We performed subgroup analysis on Asian studies and a sensitivity analysis based on the quality of the studies, type of the outcome, sample size, and whether studies considered only first-degree relatives.

RESULTS

Thirty-two relevant studies out of 612 potential abstracts (n = 80690 individuals) were included. 19.0% of the patients and 10.9% of the controls had at least one relative with gastric cancer (P < 0.00001). The pooled relative risk for the development of gastric cancer in association with a positive family history was 2.35 (95%CI: 1.96-2.81). The Cochran Q test for heterogeneity was positive (P < 0.00001, I² = 92%). After excluding the three outlier studies with the highest relative risks, heterogeneity remained significant (P < 0.00001, I² = 90%). The result was not different among Asian studies as compared to others and remained robust in several sensitivity analyses. In the 26 studies which exclusively analysed the history of gastric cancer in first-degree relatives, the relative risk was 2.71 (95%CI: 2.08-3.53; P < 0.00001).

CONCLUSION

Individuals with a first-degree relative affected with gastric cancer have a risk of about 2.5-fold for the development of gastric cancer. This could be due to genetic or environmental factors. Screening and preventive strategies should be developed for this high-risk population.

The Prevalence of Gastric Intestinal Metaplasia and Distribution of Helicobacter pylori Infection, Atrophy, Dysplasia, and Cancer in Its Subtypes

Objectives. Gastric intestinal metaplasia (IM) is frequently encountered and is considered a precursor of gastric adenocarcinoma. In the Van region of Turkey, gastric adenocarcinoma incidence is high but the prevalence of gastric IM is not known. Helicobacter pylori (H. pylori) infection is a main factor leading to atrophy, IM, and cancer development in the stomach. The aim of the current study was to investigate the prevalence of IM and its subtypes and the prevalence of H. pylori infection, atrophy, dysplasia, and cancer in gastric IM subtypes. Materials and Methods. This retrospective study was conducted on 560 IM among the 4050 consecutive patients who were undergoing esophagogastroduodenoscopy (EGD) with biopsy between June 2010 and October 2014. Clinical records and endoscopic and histopathologic reports of patients with IM were analyzed. Results. The prevalence of gastric IM was 13.8%. The prevalence of incomplete IM was statistically significantly higher than complete IM. Type III IM was the most frequent subtype. Conclusions. Gastric IM is a common finding in patients undergoing EGD with biopsy in this region. High prevalence of incomplete type IM, especially type III, can be associated with the high prevalence of gastric cancer in our region.

Preventing metachronous gastric lesions after endoscopic submucosal dissection through Helicobacter pylori eradication

BACKGROUND AND AIM

Metachronous recurrence often occurs after endoscopic submucosal dissection for early gastric cancer, and a method for preventing recurrence is unknown. We aimed to identify risk factors for metachronous lesions, and the effects of aspirin use and Helicobacter pylori eradication on preventing recurrence.

METHODS

A total of 1041 consecutive patients who underwent endoscopic submucosal dissection for early gastric cancer between January 2007 and December 2011 were retrospectively analyzed. Every patient was examined endoscopically at 2, 6, and 12 months after endoscopic submucosal dissection, and then annually. Patients were classified into the metachronous group or non-metachronous group according to the existence of metachronous lesions and subdivided by Helicobacter pylori status into three groups: not infected, eradicated after infection, and not eradicated.

RESULTS

At 39 months' median follow-up, metachronous gastric lesions had developed in 35 patients (3.4%), including 16 with dysplasia and 19 cancers. Metachronous group were significantly older than non-metachronous group (P = 0.02). Although non-metachronous group took aspirin more frequently than metachronous group (15.5% vs 5.7%), the difference was statistically insignificant (P = 0.11). In the not eradicated group, the odds ratio of metachronous lesion was 7.762 compared with the not infected group (95% confidence interval, 1.483-60.854; P = 0.02). In the eradicated group, the odd ratio of metachronous lesion was 8.120 compared with not infected group (95% confidence interval, 1.950-58.985; P = 0.01).

CONCLUSION

Helicobacter pylori infection was an independent risk factor for metachronous gastric lesions. However, eradication of Helicobacter pylori alone does not prevent all metachronous lesions in an inflamed stomach.

Gastric cancer: prevention, screening and early diagnosis

Gastric cancer continues to be an important healthcare problem from a global perspective. Most of the cases in the Western world are diagnosed at late stages when the treatment is largely ineffective. Helicobacter pylori (H. pylori) infection is a well-established carcinogen for gastric cancer. While lifestyle factors are important, the efficacy of interventions in their modification, as in the use of antioxidant supplements, is unconvincing. No organized screening programs can be found outside Asia (Japan and South Korea). Although several screening approaches have been proposed, including indirect atrophy detection by measuring pepsinogen in the circulation, none of them have so far been implemented, and more study data is required to justify any implementation. Mass eradication of H. pylori in high-risk areas tends to be cost-effective, but its adverse effects and resistance remain a concern. Searches for new screening biomarkers, including microRNA and cancer-autoantibody panels, as well as detection of volatile organic compounds in the breath, are in progress. Endoscopy with a proper biopsy follow-up remains the standard for early detection of cancer and related premalignant lesions. At the same time, new advanced high-resolution endoscopic technologies are showing promising results with respect to diagnosing mucosal lesions visually and targeting each biopsy. New histological risk stratifications (classifications), including OLGA and OLGIM, have recently been developed. This review addresses the current means for gastric cancer primary and secondary prevention, the available and emerging methods for screening, and new developments in endoscopic detection of early lesions of the stomach.

Eradication of Helicobacter pylori after endoscopic resection of gastric tumors does not reduce incidence of metachronous gastric carcinoma

BACKGROUND & AIMS

It is not clear whether eradication of Helicobacter pylori infection reduces the risk for metachronous gastric carcinoma. We performed a prospective, randomized, open-label trial of the effects of H pylori eradication on the incidence of metachronous carcinoma after endoscopic resection of gastric tumors.

METHODS

From April 2005 through February 2011 there were 901 consecutive patients with H pylori infection who had been treated with endoscopic resection for gastric dysplasia or cancer and who were assigned randomly to groups given therapy to eradicate the infection (n = 444) or no therapy (controls, n = 457). The eradication group received 20 mg omeprazole, 1 g amoxicillin, and 500 mg clarithromycin twice daily for 1 week. Patients underwent endoscopic examination 3, 6, and 12 months after treatment, and then yearly thereafter. The primary outcome was development of metachronous gastric carcinoma.

RESULTS

During a median follow-up period of 3 years, 10 patients who received H pylori eradication and 17 controls developed metachronous carcinoma; this difference was not significant (P = .15). The incidence of metachronous carcinoma between the 2 groups did not differ significantly at 1, 2, 3, and 4 years after administration of the therapy. There were no significant differences in the development of metachronous carcinoma among patients who were positive (n = 16) or negative (n = 11) for H pylori infection (P = .32).

CONCLUSIONS

In this prospective trial, eradication of H pylori after endoscopic resection of gastric tumors did not significantly reduce the incidence of metachronous gastric carcinoma. ClinicalTrials.gov Number: NCT01510730.

Efficacy of Helicobacter pylori eradication for the prevention of metachronous gastric cancer after endoscopic resection for early gastric cancer

Helicobacter pylori (H. pylori) plays an important role in gastric carcinogenesis, as the majority of gastric cancers develop from H. pylori-infected gastric mucosa. The rate of early gastric cancer diagnosis has increased in Japan and Korea, where H. pylori infection and gastric cancer are highly prevalent. Early intestinal-type gastric cancer without concomitant lymph node metastasis is usually treated by endoscopic resection. Secondary metachronous gastric cancers often develop because atrophic mucosa left untreated after endoscopic treatment confers a high risk of gastric cancer. The efficacy of H. pylori eradication for the prevention of metachronous gastric cancer remains controversial. However, in patients who undergo endoscopic resection of early gastric cancer, H. pylori eradication is recommended to suppress or delay metachronous gastric cancer. Careful and regularly scheduled endoscopy should be performed to detect minute metachronous gastric cancer after endoscopic resection.

Serum antibody against Helicobacter pylori FlaA and risk of gastric cancer

BACKGROUND

Helicobacter pylori (H. pylori) infection is a major risk factor for gastric cancer (GC); however, only a minority of infected individuals develops GC. We aim to assess the association between serostatus of antibody against H. pylori flagellin A (FlaA) and risk of GC and to evaluate the value of serum FlaA antibody as a novel screening biomarker for GC risk.

METHODS

A hospital-based case-control study including 232 cases and 264 controls was conducted. Logistic regression was adopted to analyze the association between the serostatus of FlaA antibody and risk of GC. Serum FlaA antibody was measured by an enzyme-linked immunosorbent assay (ELISA). Receiver operating characteristic (ROC) curve was used to evaluate the screening efficacy and to identify a cutoff point of serum FlaA antibody level.

RESULTS

Helicobacter pylori infection was associated with an increased risk of GC (p = .007). A positive association between serum FlaA antibody and GC risk was observed in overall subjects and H. pylori-positive subjects (OR [95% CI]: 6.8 [4.3-10.7] and 6.9 [3.6-13.4], respectively; p < .001). The seropositivity of FlaA antibody was strongly related to GC risk in a dose-dependent manner (p for trend < .001). The optimal cutoff value (OD) was 0.1403, providing a sensitivity of 74.1% and a specificity of 64.4%. The area under the ROC curve (AUC) was 0.74 in overall subjects and 0.73 in H. pylori-positive subjects, respectively.

CONCLUSIONS

FlaA was an independent risk factor for H. pylori-related GC. Serum FlaA antibody may serve as a novel noninvasive biomarker for early detection of GC.

Cost-effectiveness of screening and treating Helicobacter pylori for gastric cancer prevention

Gastric cancer is the second leading cause of cancer-related death worldwide. A meta-analysis of seven randomized controlled trials concluded that Helicobacter pylori eradication reduces gastric cancer incidence by 35%. Current consensus is that H. pylori screening and treatment is cost-effective only in high-risk populations. This paper provides an up-to-date overview of the evidence for cost-effectiveness of H. pylori screening and treatment in different population settings and risk levels for H. pylori infection. Ten unique cost-effectiveness or cost-utility analyses were identified. All found that screening for H. pylori to prevent gastric cancer in the general population costs less than $50,000 per LYG. This finding was robust for differences in H. pylori prevalence, gender and ethnicity. Based on limited evidence, re-treatment (for treatment failure), repeated screening, limiting screening and treatment to those with the CagA phenotype, or universal treatment, does not appear to be cost-effective. However, most included studies failed to consider both the broader benefits as well as the adverse effects of widespread use of antibiotics for H. pylori.

Ethnicity is a strong predictor for Helicobacter pylori infection in young women in a multi-ethnic European city

BACKGROUND AND AIM

At the same time that Helicobacter pylori prevalence is declining in Western countries, immigrants from developing countries with high H. pylori prevalence have settled in Western urban areas. Actual epidemiological data on H. pylori in a migrant community may help in realizing a more selective approach to assess H. pylori-related diseases. We aimed to define H. pylori prevalence as well as risk groups for H. pylori in a cohort of young women living in a multi-ethnic European city.

METHODS

We measured Immunoglobulin G (IgG) anti-H. pylori and CagA-antibodies in serum of pregnant women included in a population-based prospective cohort study, the Generation R study. Information on demographics and socioeconomic status was collected by questionnaires. Chi-square and logistic regression were used.

RESULTS

In total, 3146 (46%) of the 6837 tested women (mean age 29.7 ± 5.3) were H. pylori-positive and 1110 (35%) of them were CagA-positive. The H. pylori prevalence in Dutch women was 24%, which was significantly lower than in non-Dutch women (64%; P < 0.001). In particular, H. pylori positivity was found in 92% of Moroccan (odds ratio 19.2; 95% confidence interval 11.8-32.0), 80% of Cape Verdean (7.6; 5.0-11.5), 81% of Turkish (9.0; 6.7-12.1), 60% of Dutch Antillean (3.3; 2.3-4.7), and 58% of Surinamese women (3.0; 2.3-3.8). Among H. pylori-positive Dutch subjects, 19% were CagA-positive compared with 40% of the non-Dutch subjects (P < 0.001).

CONCLUSIONS

Despite a general trend of declining prevalence in Western countries, H. pylori remains highly prevalent in migrant communities, which may constitute target groups for screening and eradication to prevent H. pylori-related diseases.

Why is there a change in patterns of GE cancer?

Recent decades have seen a worrying trend in incidence rates of distal oesophageal and proximal gastric cancers. Fuelled by radical changes in lifestyle, diet, physical activity and environmental exposures, as well as an ageing population and host genetic predisposition, the incidence of oesophageal adenocarcinoma (OAC) is on the rise in Western populations. While overall incidence of gastric cancers is declining, the ageing of society means that an increase in absolute numbers is expected over coming years. Both cancers tend to present at an advanced stage, hence prognosis remains poor despite increasingly effective screening and treatment strategies. The development of gastric and oesophageal malignancies is influenced by myriad factors, not least geographical, racial and socioeconomic differences in addition to lifestyle choices. The multidimensional nature of these risk factors requires a holistic understanding of their net influence in the development of malignancy. This review explores the evidence base for established and putative risk factors in the development of gastric and oesophageal cancers. It is hoped that with a clear understanding of important risk factors, a multidisciplinary approach including effective primary prevention, regular screening of high-risk groups and continued research into the molecular biology of gastrointestinal carcinogenesis may facilitate a reduction in incidence rates, as well as early detection and optimal management of upper gastrointestinal malignancies.

Review article: biofilm formation by Helicobacter pylori as a target for eradication of resistant infection

BACKGROUND

Helicobacter pylori is one of the most common causes of bacterial infection in humans. Resistance of this infection to conventional therapies has suggested the role of a biofilm-growing bacterium, which is recalcitrant to many antimicrobial agents.

AIM

To review the current knowledge on biofilm formation by H. pylori and to discuss the implications of this behaviour in the context of human infections and their treatment.

RESULTS

Scanning electron microscopy analysis of gastric biopsies of infected patients demonstrated that H. pylori forms biofilm on the gastric mucosa epithelium. Adaptation to the biofilm environment may produce many persister cells, namely dormant cells, which are highly tolerant to antimicrobials that could account for the recalcitrance of H. pylori infections in vivo. Resistant H. pylori infection has become increasingly common with triple or quadruple therapy, even in the presence of H. pylori strains susceptible to all antibiotics. The mucolytic and thiol-containing antioxidant N-acetylcysteine, associated with antibiotics, was successfully used in clinic for therapy of patients with chronic respiratory tract infections. Consistently, N-acetylcysteine treatment prior to starting antibiotic therapy allowed the disappearance of gastric biofilm in all patients in whom H. pylori was eradicated.

CONCLUSION

Effective strategies targeting H. pylori biofilm infections are possible, through the use of substances degrading components of the biofilm.

Eradication Treatment of Helicobacter pylori Infection: Its Importance and Possible Relationship in Preventing the Development of Gastric Cancer

Helicobacter pylori is the most important carcinogen for gastric adenocarcinoma. Bacterial virulence factors are essential players in modulating the immune response involved in the initiation of carcinogenesis in the stomach; host genetic factors contribute to the regulation of the inflammatory response and to the aggravation of mucosal damage. In terms of environmental factors, salt intake and smoking contribute to the development of lesions. Various therapeutic schemes are proposed to eradicate H. pylori infection, which could potentially prevent gastric cancer, offering the greatest benefit if performed before premalignant changes of the gastric mucosa have occurred.

Mucosal barrier defects in gastric intestinal metaplasia: in vivo evaluation by confocal endomicroscopy

BACKGROUND

Helicobacter pylori infection and intestinal metaplasia (IM) are associated with gastric cancer. An impaired gastric mucosal barrier could be involved in this carcinogenesis.

OBJECTIVE

To evaluate laser confocal laser endomicroscopy (CLE) for in vivo functional imaging of mucosal barrier defects in patients with IM.

DESIGN

Prospective, controlled study.

SETTING

A tertiary-care academic center.

PATIENTS

This study involved patients with IM of the gastric mucosa who underwent CLE for surveillance.

INTERVENTIONS

Specific IM mucosa and non-IM mucosa in patients were identified by CLE, and targeted biopsy samples were taken for histopathology and electron microscopy.

MAIN OUTCOME MEASUREMENTS

Post-CLE assessment of paracellular fluorescein leakage was devised and validated by electron microscopy. We also evaluated the effect of H pylori eradication on the mucosal barrier.

RESULTS

Forty-two patients were included. Of non-IM samples, the paracellular permeability was significantly increased in H pylori-positive samples compared with H pylori-negative controls (54 ± 31% vs 3 ± 6%, P < .05). Of IM samples, the permeability was significantly increased in both H pylori-negative and H pylori-positive samples (67 ± 34% and 72 ± 28% vs 3 ± 6%, both P < .05). The results of post-CLE assessment correlated well with the electron microscopy findings (R(2) 0.834, P < .0001). After the eradication of H pylori, the paracellular barrier dysfunction of non-IM mucosa was significantly improved as shown by electron microscopy and CLE (both P < .001). However, there was no significant change in IM mucosa.

LIMITATIONS

Single-center study.

CONCLUSIONS

CLE allows functional imaging of mucosal barrier defects. Gastric IM is associated with an impaired paracellular barrier irrespective of H pylori eradication.

Quality of RCTs exploring Helicobacter pylori eradication for the prevention of gastric cancer and preneoplastic lesions

Randomized controlled trials (RCTs) are considered the gold standard for evaluating the efficacy of clinical interventions and developing evidence-based clinical practice guidelines; however, they can yield biased results when their methodology is less than rigorous, or their published reports fail to report key items. A number of RCTs have been carried out to explore the relationship between Helicobacter pylori eradication and gastric cancer, but their results remain controversial. In this article, we will comprehensively review searched medical electronic databases, and appraise the reporting and methodological quality of these relevant RCTs according to the Consolidated Standards of Reporting Trials 2010 statement and the Cochrane Handbook in order to learn about the internal and external validity of these RCTs.

The diagnosis and management of gastric cancer: expert discussion and recommendations from the 12th ESMO/World Congress on Gastrointestinal Cancer, Barcelona, 2010

Well-recognized experts in the field of gastric cancer discussed during the 12th European Society Medical Oncology (ESMO)/World Congress Gastrointestinal Cancer (WCGIC) in Barcelona many important and controversial topics on the diagnosis and management of patients with gastric cancer. This article summarizes the recommendations and expert opinion on gastric cancer. It discusses and reflects on the regional differences in the incidence and care of gastric cancer, the definition of gastro-esophageal junction and its implication for treatment strategies and presents the latest recommendations in the staging and treatment of primary and metastatic gastric cancer. Recognition is given to the need for larger and well-designed clinical trials to answer many open questions.

Why is the coexistence of gastric cancer and duodenal ulcer rare? Examination of factors related to both gastric cancer and duodenal ulcer

The coexistence of gastric cancer with duodenal ulcer has been found empirically to be rare, but why it is rare is difficult to explain satisfactorily. To elucidate this question, we carried out a literature review of the subject. The frequency with which the two diseases coexist is 0.1-1.7%, and the main factor associated with both gastric cancer and duodenal ulcer is Helicobacter pylori infection. However, there are marked differences between the disorders of hyperchlorhydria in duodenal ulcer, and hypochlorhydria in gastric cancer. The most acceptable view of the reason for the difference may be that the acquisition of H. pylori infection occurs mainly in childhood, so that the time of acquisition of atrophic gastritis may be the most important, and if atrophic gastritis is not acquired early, high levels of gastric acid may occur, and consequently acute antral gastritis and duodenal ulcer may occur in youth, whereas, in elderly individuals, persistent H. pylori infections and the early appearance of atrophic gastritis may be the causes of low gastric acid, and consequently gastric cancer may occur. In patients with duodenal ulcer, factors such as nonsteroidal anti-inflammatory drugs (NSAIDs) and dupA-H. pylori strains may contribute to preventing the early acquisition of atrophic gastritis, while acid-suppressive therapy and vascular endothelial growth factor and other entities may inhibit atrophic gastritis. In contrast, in gastric cancer, factors such as excessive salt intake, acid-suppressive therapy, polymorphisms of inflammatory cytokines, and the homB-H. pylori strain may contribute to the early acquisition of atrophic gastritis, while factors such as NSAIDs; fruits and vegetables; vitamins A, C, and E; and good nutrition may inhibit it.

Synthesis and antimicrobial evaluation of nitazoxanide-based analogues: identification of selective and broad spectrum activity

A library composed of nitazoxanide-based analogues was synthesized and assayed for increased antibacterial efficacy against the pyruvate-ferredoxin oxidoreductase (PFOR) using microorganisms Helicobacter pylori, Campylobacter jejuni and Clostridium difficile. Derivatives were found to recapitulate and improve activity against these organisms and select analogues were tested for their ability to disrupt the PFOR enzyme directly. The library was also screened for activity against staphylococci and resulted in the identification of analogues capable of inhibiting both staphylococci and all PFOR organisms at low micromolar minimum inhibitory concentrations with low toxicity to human foreskin cells.

Helicobacter pylori and gastric cancer

Gastric cancer remains a major cause of cancer death worldwide. The discovery of Helicobacter pylori Helicobacter pylori and its association with gastric cancer has opened up new insights into its pathogenesis. Gastric cancer pathogenesis is the result of a complex interplay between bacterial, host and environmental factors resulting in a step wise histological progression to neoplasia. H. pylori is a major factor in the early stages of cancer development and the mechanism of action of its virulence factors are being steadily unravelled. It is also now recognised that host genetic polymorphisms also play a complex role interacting synergistically with the bacterial virulence factors. The role of H. pylori in the causation of gastric cancer also raises the possibility of cancer prevention through screening and eradication, actions which may improve outcomes in high risk populations but which may not be cost-effective in areas of low risk. Ultimately, despite the vast improvements in knowledge, as yet there has not been a corresponding improvement in terms of gastric cancer survival rates.

Ureases as a target for the treatment of gastric and urinary infections

Urease is known to be a major contributor to pathologies induced by Helicobacter pylori and Proteus species. In H pylori, urease allows the bacteria to survive in an acidic gastric environment during colonisation, playing an important role in the pathogenesis of gastric and peptic ulcers. Ureolytic activity also results in the production of ammonia in close proximity to the gastric epithelium, causing cell damage and inflammation. In the case of Proteus species (notably Proteus mirabilis) infection, stones are formed due to the presence of ammonia and carbon dioxide released by urease action. In addition, the ammonia released is able to damage the glycosaminoglycan layer, which protects the urothelial surface against bacterial infection. In this context, the administration of urease inhibitors may be an effective therapy for urease-dependent pathogenic bacteria. This is a review of the role of ureases in H pylori and Proteus species infections, focussing on the biochemical and clinical aspects of the most promising and/or potent urease inhibitors for the treatment of gastric and urinary tract infections.

Biological activity of modified and exchanged 2-amino-5-nitrothiazole amide analogues of nitazoxanide

Head group analogues of the antibacterial and antiparasitic drug nitazoxanide (NTZ) are presented. A library of 39 analogues was synthesized and assayed for their ability to suppress growth of Helicobacter pylori, Campylobacter jejuni, Clostridium difficile and inhibit NTZ target pyruvate:ferredoxin oxidoreductase (PFOR). Two head groups assayed recapitulated NTZ activity and possessed improved activity over their 2-amino-5-nitrothiazole counterparts, demonstrating that head group modification is a viable route for the synthesis of NTZ-related antibacterial analogues.

Gastric cancers in Finnish patients after cure of Helicobacter pylori infection: A cohort study

Helicobacter pylori infection is associated with gastric cancer. A total of 97% of the infected subjects have elevated levels of H. pylori antibodies. The antibody titers have been shown to decline rapidly (40-60% within 4-12 months) only after successful eradication therapy. We allocated 26,700 consecutive patients tested during 1986-1998 for H. pylori antibodies to 3 subcohorts: seropositive patients with rapidly falling antibody titers (Hp+CURED, n = 3,650), seropositive patients where no serological information indicating cure was obtained (Hp+NoInfo, n = 11,638) and seronegative patients (Hp-, n = 11,422). In the subcohorts, the standardised incidence ratios (SIRs) with 95% confidence intervals (CI) were defined for subsequent cancers of stomach, pancreas, colon, rectum, breast and prostate separately and for all cancers except stomach combined. The mean follow-up time was 10.1 years and the number of gastric cancers was 72. For the Hp+CURED, the SIR for gastric cancers for the first 5 follow-up years was 1.62 but decreased from the sixth follow-up year thereon to 0.14 (CI: 0.00-0.75). Likewise, the risk ratio, defined in a Poisson regression analysis using the Hp+NoInfo group as the reference, decreased from 1.60 to 0.13 (CI: 0.02-1.00, p = 0.049). The SIR for Hp- was not significantly higher than that for Hp+NoInfo for any of the cancers analysed. To conclude, cured H. pylori infection led to a significantly decreased incidence of gastric cancers from the sixth follow-up year. Advanced atrophic gastritis would be a plausible contributor to the elevated SIR in elderly Hp- patients.

Helicobacter pylori and gastric adenocarcinoma

Gastric cancer is the second most common cause of cancer death worldwide. A large body of evidence supports a causal role of Helicobacter pylori in the majority of gastric malignancies. Great strides have been made in understanding the pathogenesis of this relationship, but much remains to be learned. Moreover, because of the high prevalence of infection, the lack of definitive trials, and the challenges of H. pylori treatment, there remains no consensus on the role of routine screening and treatment of this infection to prevent cancer. This article reviews the current knowledge on H. pylori and gastric cancer and presents some of the clinical and public health challenges associated with this pathogen.

Guidelines for the management of Helicobacter pylori infection in Japan: 2009 revised edition

BACKGROUND

Over the past few years, the profile of Helicobacter pylori infection has changed in Japan. In particular, the relationship between H. pylori and gastric cancer has been demonstrated more clearly. Accordingly, the committee of the Japanese Society for Helicobacter Research has revised the guidelines for diagnosis and treatment of H. pylori infection in Japan.

MATERIALS AND METHODS

Four meetings of guidelines preparation committee were held from July 2007 to December 2008. In the new guidelines, recommendations for treatment have been classified into five grades according to the Minds Recommendation Grades, while the level of evidence has been classified into six grades. The Japanese national health insurance system was not taken into consideration when preparing these guidelines.

RESULTS

Helicobacter pylori eradication therapy achieved a Grade A recommendation, being useful for the treatment of gastric or duodenal ulcer, for the treatment and prevention of H. pylori-associated diseases such as gastric cancer, and for inhibiting the spread of H. pylori infection. Levels of evidence were determined for each disease associated with H. pylori infection. For the diagnosis of H. pylori infection, measurement of H. pylori antigen in the feces was added to the tests not requiring biopsy. One week of proton-pump inhibitor-based triple therapy (including amoxicillin and metronidazole) was recommended as second-line therapy after failure of first-line eradication therapy.

CONCLUSION

The revised Japanese guidelines for H. pylori are based on scientific evidence and avoid the administrative restraints that applied to earlier versions.

Role of Helicobacter pylori infection in gastric cancer pathogenesis: a chance for prevention

Gastric cancer in the absence of strategies implemented for early detection continues to have a dismal prognosis. There are limited options for a curative therapy once patients present with clinical manifestations of this malignant disease. Helicobacter pylori (H. pylori) infection plays a key role in gastric carcinogenesis, supported by epidemiological, preclinical and clinical studies. The recognition of H. pylori infection as a critical risk factor in the development of gastric cancer opens the chance for new venues in prevention strategies.

Cost-effectiveness of eradication of Helicobacter pylori in gastric cancer survivors after endoscopic resection of early gastric cancer

BACKGROUND

Clinical effectiveness of Helicobacter pylori eradication in gastric cancer survivors after endoscopic resection of early gastric cancer (EGC) was recently established in a randomized controlled trial. We aimed to establish long-term cost-effectiveness in gastric cancer survivors after endoscopic resection of EGC.

MATERIALS AND METHODS

A Markov model was constructed to compare the costs and outcomes of the two intervention strategies: (1) eradicate H. pylori after complete resection of EGC by endoscopy (2) do not eradicate. Estimates for variables in the model were obtained by extensive review of published reports. Analyses were made from the Korean public healthcare provider's perspective.

RESULTS

Base-case analysis indicated H. pylori eradication costs less (US$ 29,780 vs. US$ 30,594) than no eradication, and save more lives (mean life expectancy from eradication: 13.60 years vs. 13.55 years). One-way and three-way sensitivity analyses showed the robustness of the cost-effectiveness results.

CONCLUSION

In this selective population with very high risk of developing gastric cancer, H. pylori eradication should be considered for reimbursement with priority to prevent subsequent cancer and also reduce health care cost.

Early Helicobacter pylori eradication decreases risk of gastric cancer in patients with peptic ulcer disease

BACKGROUND & AIMS

Helicobacter pylori (H pylori) is a risk factor for gastric cancer. We investigated whether early H pylori eradication is associated with gastric cancer risk in patients with peptic ulcer diseases.

METHODS

This nationwide cohort study was based on the Taiwan National Health Insurance Database (NHID), which provided data on 80,255 patients who were hospitalized for the first time between 1997 and 2004 with a primary diagnosis of peptic ulcer diseases and received H pylori eradication therapy. The patient population was divided into early (within 1 year) and late (after 1 year) eradication cohorts; standardized incidence ratios (SIRs) and hazards ratios (HRs) were determined.

RESULTS

There was no significant difference in gastric cancer risk between patients who received early H pylori eradication and the general population (SIR, 1.05; 95% confidence interval [CI]: 0.96-1.14), but late eradication was associated with an increased risk (SIR, 1.36; 95% CI: 1.24-1.49). In gastric ulcer patients who received early eradication, SIRs of gastric cancer decreased from 1.60 at 3-4 years to 1.05 at 7-10 years after hospitalization; the SIRs decreased from 0.57 to 0.33 for duodenal ulcer patients over the same period. Among patients who received late eradication, SIRs decreased from 2.14 to 1.32 for those with gastric ulcers and from 0.90 to 0.66 for those with duodenal ulcers. Early H pylori eradication (HR, 0.77) and frequent aspirin or nonsteroidal anti-inflammatory drug use (HR, 0.65) were independent protective factors for gastric cancer.

CONCLUSIONS

Early H pylori eradication is associated with decreased risk of gastric cancer in patients with peptic ulcer diseases.

Gastric cancer mortality trends in Spain, 1976-2005, differences by autonomous region and sex

BACKGROUND

Gastric cancer is the second leading cause of oncologic death worldwide. One of the most noteworthy characteristics of this tumor's epidemiology is the marked decline reported in its incidence and mortality in almost every part of the globe in recent decades. This study sought to describe gastric cancer mortality time trends in Spain's regions for both sexes.

METHODS

Mortality data for the period 1976 through 2005 were obtained from the Spanish National Statistics Institute. Cases were identified using the International Classification of Diseases 9th and 10th revision (codes 151 and C16, respectively). Crude and standardized mortality rates were calculated by geographic area, sex, and five-year period. Joinpoint regression analyses were performed to ascertain whether changes in gastric cancer mortality trends had occurred, and to estimate the annual percent change by sex and geographic area.

RESULTS

Gastric cancer mortality decreased across the study period, with the downward trend being most pronounced in women and in certain regions situated in the interior and north of mainland Spain. Across the study period, there was an overall decrease of 2.90% per annum among men and 3.65% per annum among women. Generally, regions in which the rate of decline was sharpest were those that had initially registered the highest rates. However, the rate of decline was not constant throughout the study period: joinpoint analysis detected a shift in trend for both sexes in the early 1980s.

CONCLUSION

Gastric cancer mortality displayed in both sexes a downward trend during the study period, both nationally and regionally. The different trend in rates in the respective geographic areas translated as greater regional homogeneity in gastric cancer mortality by the end of the study period. In contrast, rates in women fell more than did those in men. The increasing differences between the sexes could indicate that some risk factors may be modifying the sex-specific pattern of this tumor.

Does Helicobacter pylori eradication therapy for peptic ulcer prevent gastric cancer?

AIM

To investigate the effects of Helicobacter pylori (H pylori) eradication therapy for treatment of peptic ulcer on the incidence of gastric cancer.

METHODS

A multicenter prospective cohort study was conducted between November 2000 and December 2007 in Yamagata Prefecture, Japan. The study included patients with H pylori-positive peptic ulcer who decided themselves whether to receive H pylori eradication (eradication group) or conventional antacid therapy (non-eradication group). Incidence of gastric cancer in the two groups was determined based on the results of annual endoscopy and questionnaire surveys, as well as Yamagata Prefectural Cancer Registry data, and was compared between the two groups and by results of H pylori therapy.

RESULTS

A total of 4133 patients aged between 13 and 91 years (mean 52.9 years) were registered, and 56 cases of gastric cancer were identified over a mean follow-up of 5.6 years. The sex- and age-adjusted incidence ratio of gastric cancer in the eradication group, as compared with the non-eradication group, was 0.58 (95% CI: 0.28-1.19) and ratios by follow-up period (< 1 year, 1-3 years, > 3 years) were 1.16 (0.27-5.00), 0.50 (0.17-1.49), and 0.34 (0.09-1.28), respectively. Longer follow-up tended to be associated with better prevention of gastric cancer, although not to a significant extent. No significant difference in incidence of gastric cancer was observed between patients with successful eradication therapy (32/2451 patients, 1.31%) and those with treatment failure (11/639 patients, 1.72%). Among patients with duodenal ulcer, which is known to be more prevalent in younger individuals, the incidence of gastric cancer was significantly less in those with successful eradication therapy (2/845 patients, 0.24%) than in those with treatment failure (3/216 patients, 1.39%).

CONCLUSION

H pylori eradication therapy for peptic ulcer patients with a mean age of 52.9 years at registration did not significantly decrease the incidence of gastric cancer.

Bactericidal activities of the cationic steroid CSA-13 and the cathelicidin peptide LL-37 against Helicobacter pylori in simulated gastric juice

BACKGROUND

The worldwide appearance of drug-resistant strains of H. pylori motivates a search for new agents with therapeutic potential against this family of bacteria that colonizes the stomach, and is associated with adenocarcinoma development. This study was designed to assess in vitro the anti-H. pylori potential of cathelicidin LL-37 peptide, which is naturally present in gastric juice, its optimized synthetic analog WLBU2, and the non-peptide antibacterial agent ceragenin CSA-13.

RESULTS

In agreement with previous studies, increased expression of hCAP-18/LL-37 was observed in gastric mucosa obtained from H. pylori infected subjects. MBC (minimum bactericidal concentration) values determined in nutrient-containing media range from 100-800 microg/ml for LL-37, 17.8-142 microg/ml for WLBU2 and 0.275-8.9 microg/ml for ceragenin CSA-13. These data indicate substantial, but widely differing antibacterial activities against clinical isolates of H. pylori. After incubation in simulated gastric juice (low pH with presence of pepsin) CSA-13, but not LL-37 or WLBU2, retained antibacterial activity. Compared to LL-37 and WLBU2 peptides, CSA-13 activity was also more resistant to inhibition by isolated host gastric mucins.

CONCLUSION

These data indicate that cholic acid-based antimicrobial agents such as CSA-13 resist proteolytic degradation and inhibition by mucin and have potential for treatment of H. pylori infections, including those caused by the clarithromycin and/or metronidazole-resistant strains.