Helicobacter pylori test-and-treat program can be cost-effective to prevent gastric cancer in Taiwanese adults: referred to the nationwide reimbursement database

Cost-Effectiveness of Population-Based Helicobacter pylori Screening With Eradication for Optimal Age of Implementation

BACKGROUND

Helicobacter pylori screening with eradication reduces gastric cancer (GC) development. However, it was unknown at what age the H. pylori screening should be implemented to achieve the greatest benefits at the least cost. This study aimed to determine the optimal age of H. pylori screening for primary GC prevention.

MATERIALS AND METHODS

A state transition model for a hypothetical cohort of 15-year-olds from a healthcare payer perspective on a lifetime horizon was developed. Nine ages for H. pylori testing were considered: 15, 18, 20, 30, 40, 50, 60, 70, and 80 years. H. pylori screening was compared with no screening and annual, biennial, and triennial endoscopies starting at age 50. The main outcomes were costs, quality-adjusted life-years (QALYs), life expectancy life-years (LYs), incremental cost-effectiveness ratios, GC cases, stage I GC cases, and GC-related deaths. One-way, two-way, and probabilistic sensitivity analyses were performed to assess the uncertainty of the parameters.

RESULTS

All H. pylori screenings at ages 15-80 were more cost-effective than all endoscopies and no screening. H. pylori screening at age 15 yielded the greatest cost-saving and benefits. The cost-effectiveness was sensitive to the adherence rate of H. pylori screening at age 15. Cost-effectiveness acceptability curves showed that H. pylori screening at age 15 was 99.6% cost-effective at a willingness-to-pay threshold of US$50,000 per QALY gained. Compared with no screening and biennial endoscopy in 15.6 million 15-year-olds from 2022 to 2037, respectively, H. pylori screening at age 15 saves US$9.70 million and US$2.39 billion, increases 1.26 million QALYs with 1312 LYs and 651 LYs, prevents 436 GC cases with 254 stage I GC cases and 305 stage I GC cases, and avoids 176 GC-related deaths and 72 GC-related deaths.

CONCLUSIONS

The optimal age for population-based H. pylori screening at ages 15-80 is the youngest, 15 years old. Shifting population-based H. pylori screening to younger people will reduce GC morbidity and mortality worldwide, along with a detailed investigation of the feasibility and long-term consequences of H. pylori eradication at a young age.

Evolution of the Correa's cascade steps: A long-term endoscopic surveillance among non-ulcer dyspepsia and gastric ulcer after H. pylori eradication

BACKGROUND

This study is aimed toward investigating the evolution of each Correa's step after Helicobacter pylori eradication in a long-term follow-up and exploring the factors correlated with a high-risk of gastric cancer.

METHODS

A total of 1824 H. pylori-infected subjects were enrolled to receive screening endoscopy. Among them, 491 received surveillance endoscopy. The patients were divided into Correa's steps I to VI, from normal to gastric cancer. A group-based trajectory model was used to classify patients as persistent high-risk status or not.

RESULTS

The prevalence rates of positive corpus-predominant gastritis index (CGI) were 20%-40% in all age groups and Correa's steps IV-V increased >35% after 50 years based on screening endoscopy. Successful eradication of H. pylori regressed CGI after the 1st year-and-thereafter (P < 0.05) and decreased Correa's step progression (Relative risk 0.66 [95% CI 0.49-0.89], P = 0.01); however, it did not regress OLGA and OLGIM. Not only in steps IV-V, but also in step III, the patients had a risk of developing gastric cancer (11.13-76.41 and 4.61 per 1000 person-years). Age (Hazard ratio 1.012 [1.003-1.020], P = 0.01), OLGA stages ≥ I (2.127 [1.558-2.903], P < 0.001), and OLGIM stages ≥ I (1.409 [1.119-1.774], P = 0.004) were correlated independently with a persistent high-risk status.

CONCLUSION

The patients in Correa's steps III-V, but not I-II, were at risk of gastric cancer after H. pylori eradication. Age, OLGA stages ≥ I, and OLGIM stages ≥ I were independent factors correlated to a persistent high-risk of gastric cancer. The data may be useful when scheduling surveillance endoscopy for subjects in each Correa's step (NCT04527055).

Mass screening and eradication of Helicobacter pylori as the policy recommendations for gastric cancer prevention

Gastric cancer is an inflammation-related cancer triggered by Helicobacter pylori infection. Understanding of the natural disease course has prompted the hypothesis that gastric cancer can be prevented by administering a short-course antibiotic treatment to eradicate the H. pylori infection and interrupt this carcinogenic cascade. Results from randomized controlled trials and cohort studies have repeatedly confirmed this concept, which has moved attention from individual management of H. pylori infection to population-wide implementation of screening programs. Such a paradigm shift follows a three-tier architecture. First, healthcare policy-makers determine the most feasible and applicable eligibility, invitation, testing, referral, treatment, and evaluation methods for an organized screening program to maximize the population benefits and cost-effectiveness. Second, provision of knowledge and effective feedback to frontline general practitioners, including choice of diagnostic tests, selection of eradication regimens, and the indication of endoscopic examination, ensures the quality of care and increases the likelihood of desired treatment responses. Third, initiatives to raise population awareness are designed regarding the impact of H. pylori infection and risky lifestyle habits on the stomach health. These programs, with increased accessibility and geographic coverage in progress, will accelerate the decline in morbidity, mortality, and associated costs of this preventable malignancy.

Management of Helicobacter pylori infection: the Maastricht VI/Florence consensus report

Helicobacter pyloriInfection is formally recognised as an infectious disease, an entity that is now included in the International Classification of Diseases 11th Revision. This in principle leads to the recommendation that all infected patients should receive treatment. In the context of the wide clinical spectrum associated with Helicobacter pylori gastritis, specific issues persist and require regular updates for optimised management.The identification of distinct clinical scenarios, proper testing and adoption of effective strategies for prevention of gastric cancer and other complications are addressed. H. pylori treatment is challenged by the continuously rising antibiotic resistance and demands for susceptibility testing with consideration of novel molecular technologies and careful selection of first line and rescue therapies. The role of H. pylori and antibiotic therapies and their impact on the gut microbiota are also considered.Progress made in the management of H. pylori infection is covered in the present sixth edition of the Maastricht/Florence 2021 Consensus Report, key aspects related to the clinical role of H. pylori infection were re-evaluated and updated. Forty-one experts from 29 countries representing a global community, examined the new data related to H. pylori infection in five working groups: (1) indications/associations, (2) diagnosis, (3) treatment, (4) prevention/gastric cancer and (5) H. pylori and the gut microbiota. The results of the individual working groups were presented for 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 various clinical fields.

Economic and health impacts of introducing Helicobacter pylori eradication strategy into national gastric cancer policy in Japan: A cost-effectiveness analysis

BACKGROUND

Helicobacter pylori (H. pylori) eradication reduces gastric cancer risk. Since 2013, a population-wide H. pylori eradication strategy for patients with chronic gastritis has begun to prevent gastric cancer in Japan. The aim of this study was to evaluate the economic and health effects of H. pylori eradication strategy in national gastric cancer prevention program.

MATERIALS AND METHODS

We developed a cohort state-transition model for H. pylori eradication and no eradication over a lifetime horizon from a healthcare payer perspective, and performed one-way and probabilistic sensitivity analyses. We targeted a hypothetical cohort of H. pylori-positive patients aged 20, 30, 40, 50, 60, 70, and 80. The main outcomes were costs, quality-adjusted life-years (QALYs), life expectancy life-years (LYs), incremental cost-effectiveness ratios, gastric cancer cases, and deaths from gastric cancer.

RESULTS

H. pylori eradication was more effective and cost-saving for all age groups than no eradication. Sensitivity analyses showed strong robustness of the results. From 2013-2019 for 8.50 million patients, H. pylori eradication saved US$3.75 billion, increased 11.11 million QALYs and 0.45 million LYs, and prevented 284,188 cases and 65,060 deaths. For 35.59 million patients without eradication, H. pylori eradication has the potential to save US$14.82 billion, increase 43.10 million QALYs and 1.66 million LYs, and prevent 1,084,532 cases and 250,256 deaths.

CONCLUSIONS

National policy using population-wide H. pylori eradication to prevent gastric cancer has significant cost savings and health impacts for young-, middle-, and old-aged individuals in Japan. The findings strongly support the promotion of H. pylori eradication strategy for all age groups in high-incidence countries.

Helicobacter pylori Infection in Geriatric Patients: Current Situation and Treatment Regimens

Helicobacter pylori (H. pylori) has so far infected more than half the global population. It is the most important and controllable risk factor for gastric cancer. The elderly, who are at a higher incidence of the infection, are also commonly found to develop antibiotic resistance. The symptoms, diagnosis, clinical features (of gastric or extra-digestive diseases), and treatment of H. pylori infection in the elderly, are different from that in the non-elderly. Health conditions, including comorbidities and combined medication have limited the use of regular therapies in elderly patients. However, they can still benefit from eradication therapy, thus preventing gastric mucosal lesions and gastric cancer. In addition, new approaches, such as dual therapy and complementary therapy, have the potential to treat older patients with H. pylori infection.

Screening and eradication of Helicobacter pylori for gastric cancer prevention: the Taipei global consensus

OBJECTIVE

A global consensus meeting was held to review current evidence and knowledge gaps and propose collaborative studies on population-wide screening and eradication of Helicobacter pylori for prevention of gastric cancer (GC).

METHODS

28 experts from 11 countries reviewed the evidence and modified the statements using the Delphi method, with consensus level predefined as ≥80% of agreement on each statement. The Grading of Recommendation Assessment, Development and Evaluation (GRADE) approach was followed.

RESULTS

Consensus was reached in 26 statements. At an individual level, eradication of H. pylori reduces the risk of GC in asymptomatic subjects and is recommended unless there are competing considerations. In cohorts of vulnerable subjects (eg, first-degree relatives of patients with GC), a screen-and-treat strategy is also beneficial. H. pylori eradication in patients with early GC after curative endoscopic resection reduces the risk of metachronous cancer and calls for a re-examination on the hypothesis of 'the point of no return'. At the general population level, the strategy of screen-and-treat for H. pylori infection is most cost-effective in young adults in regions with a high incidence of GC and is recommended preferably before the development of atrophic gastritis and intestinal metaplasia. However, such a strategy may still be effective in people aged over 50, and may be integrated or included into national healthcare priorities, such as colorectal cancer screening programmes, to optimise the resources. Reliable locally effective regimens based on the principles of antibiotic stewardship are recommended. Subjects at higher risk of GC, such as those with advanced gastric atrophy or intestinal metaplasia, should receive surveillance endoscopy after eradication of H. pylori.

CONCLUSION

Evidence supports the proposal that eradication therapy should be offered to all individuals infected with H. pylori. Vulnerable subjects should be tested, and treated if the test is positive. Mass screening and eradication of H. pylori should be considered in populations at higher risk of GC.

Cost-effectiveness analysis of screen-and-treat strategy in asymptomatic Chinese for preventing Helicobacter pylori-associated diseases

BACKGROUND

The high prevalence of Helicobacter pylori (H pylori) infection in China results in a substantial public health burden. Medical experts have not agreed on the best solution of population intervention for this problem. We presented a health economic evaluation of a population-based H pylori screen-and-treat strategy for preventing gastric cancer, peptic ulcer disease (PUD), and nonulcer dyspepsia (NUD).

MATERIALS AND METHODS

Decision trees and Markov models were developed to evaluate the cost-effectiveness of H pylori screening followed by eradication treatment in asymptomatic Chinese. The modeled screen-and-treat strategy reduced the risk of gastric cancer, PUD, and NUD. The main outcomes were the costs, effectiveness, and the incremental cost-effectiveness ratio. Uncertainty was explored by one-way and probabilistic sensitivity analyses.

RESULTS

For preventing gastric cancer, PUD, and NUD together in a cohort of 10 million asymptomatic Chinese at the age of 20 years, the H pylori screen-and-treat strategy saved 288.1 million dollars, 28 989 life years, and 111 663 quality-adjusted life years, and prevented 11 611 gastric cancers, 5422 deaths from gastric cancer, and 1854 deaths from PUD during life expectancy. Uncertainty of screening age from 20 to 60 did not affect the superiority of the screen-and-treat strategy over the no-screen strategy. The one-way and probabilistic sensitivity analyses confirmed the robustness of our study's results.

CONCLUSIONS

Compared with the no-screen strategy, population-based screen-and-treat strategy for H pylori infection proved cheaper and more effective for preventing gastric cancer, PUD, and NUD in Chinese asymptomatic general population.

Higher risk of gastric cancer among immigrants to Ontario: a population-based matched cohort study with over 2 million individuals

BACKGROUND

The risk of gastric carcinoma (GC) varies around the world and between females and males. We aimed to compare the risk of GC among immigrants to Ontario, Canada, to the risk of GC in its general population.

METHODS

This was a retrospective population-based matched cohort study from 1991 to 2014. We identified immigrants who were first eligible for the Ontario Health Insurance Plan at age 40 years or older, and matched 5 controls by year of birth and sex. We calculated crude rates and relative rates of GC stratified by sex. We modeled GC hazard using multivariable Cox proportional hazards regression, where a time-varying coefficient was incorporated to examine changes in the association of immigrant status with GC hazard over time.

RESULTS

Among females, 415 GC cases were identified among 209,843 immigrants and 1872 among 1,049,215 controls. Among males, 596 GC cases were identified among 191,792 immigrants and 2998 among 958,960 controls. Comparing immigrants from East Asia and Pacific with the controls, the crude relative rate of GC was 1.54 for females and 1.32 for males. The adjusted hazard ratio (HR) for GC among female immigrants was 1.29 [95% confidence interval (CI) 1.12, 1.48] within 10 years and 1.19 (1.01, 1.40) beyond 10 years; for males, the HR was 1.17 (1.04, 1.31) within 10 years and 1.00 (0.87, 1.15) beyond 10 years.

CONCLUSION

The risk of GC among immigrants is elevated. Although high-risk immigrant populations in Ontario have been identified, further knowledge is required before a program of GC prevention that is targeted to them can be planned.

Helicobacter pylori management in ASEAN: The Bangkok consensus report

Helicobacter pylori (H. pylori) infection remains to be the major cause of important upper gastrointestinal diseases such as chronic gastritis, peptic ulcer, gastric adenocarcinoma, and mucosa-associated lymphoid tissue lymphoma. H. pylori management in ASEAN: the Bangkok consensus report gathered key opinion leaders for the region to review and evaluate clinical aspects of H. pylori infection and to develop consensus statements, rationales, and grades of recommendation for the management of H. pylori infection in clinical practice in ASEAN countries. This ASEAN Consensus consisted of 34 international experts from 10 ASEAN countries, Japan, Taiwan, and the United States. The meeting mainly focused on four issues: (i) epidemiology and disease association; (ii) diagnostic tests; (iii) management; and (iv) follow-up after eradication. The final results of each workshop were presented for consensus voting by all participants. Statements, rationale, and recommendations were developed from the available current evidence to help clinicians in the diagnosis and treatment of H. pylori and its clinical diseases.

Cost-effective options for the prevention and management of gastrointestinal and liver disease in the Asia-Pacific region

The Asia-Pacific region contains more than half of the world's population and is markedly heterogeneous in relation to income levels and the provision of public and private health services. For low-income countries, the major health priorities are child and maternal health. In contrast, priorities for high-income countries include vascular disease, cancer, diabetes, dementia, and mental health disorders as well as chronic inflammatory disorders such as hepatitis B and hepatitis C. Cost-effectiveness analyses are methods for assessing the gains in health relative to the costs of different health interventions. Methods for measuring health outcomes include years of life saved (or lost), quality-adjusted life years, and disability-adjusted life years. The incremental cost-effectiveness ratio measures the cost (usually in US dollars) per life year saved, quality-adjusted life year gained, or disability-adjusted life year averted of one intervention relative to another. In low-income countries, approximately 50% of infant deaths (< 5 years) are caused by gastroenteritis, the major pathogen being rotavirus infection. Rotavirus vaccines appear to be cost-effective but, thus far, have not been widely adopted. In contrast, infant vaccination for hepatitis B is promoted in most countries with a striking reduction in the prevalence of infection in vaccinated individuals. Cost-effectiveness analyses have also been applied to newer and more expensive drugs for hepatitis B and C and to government-sponsored programs for the early detection of hepatocellular, gastric, and colorectal cancer. Most of these studies reveal that newer drugs and surveillance programs for cancer are only marginally cost-effective in the setting of a high-income country.

The corpus-predominant gastritis index can be an early and reversible marker to identify the gastric cancer risk of Helicobacter pylori-infected nonulcer dyspepsia

BACKGROUND

Corpus-predominant gastritis index (CGI) is an early histological marker to identify Helicobacter pylori-infected gastric cancer relatives at risk of cancer. This study validated whether CGI is more prevalent in H. pylori-infected nonulcer dyspepsia (NUD) subjects than in duodenal ulcer (DU) controls and whether it is reversible after H. pylori eradication or is correlated with noninvasive biomarkers.

MATERIALS AND METHODS

In this longitudinal cohort study, 573 H. pylori-infected subjects were enrolled, including 349 NUD and 224 DU. Gastric specimens were provided to assess CGI, spasmolyic polypeptide-expressing metaplasia (SPEM), and Operative Link on Gastric Intestinal Metaplasia assessment (OLGIM). Serum pepsinogen I and II levels were assessed using enzyme-linked immunosorbent assay. CGI subjected were followed up at least 1 year after H. pylori eradication.

RESULTS

NUD subjects had higher prevalence rates of CGI (47.0% vs 29.9%, P<.001) and OLGIM stages III-IV (24.1% vs 15.2%, P=.01) than controls. CGI was highly prevalent in NUD subjects after the age of 40, which was 10 years earlier than atrophic gastritis and intestinal metaplasia. NUD subjects with CGI had higher risk of SPEM (OR 2.86, P<.001) and lower serum pepsinogen I/II ratios (P<.001) than those without CGI. Serum pepsinogen I/II ratios <9 could predict CGI modestly (AUROC 0.69, 95% CI: 0.63-0.74). CGI was regressed after eradication (P<.001).

CONCLUSIONS

CGI was more prevalent in H. pylori-infected NUD subjects than in controls, was correlated with SPEM, and may serve as a marker earlier than OLGIM to indicate risk of gastric cancer. Moreover, CGI could be regressed after eradication.

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.

A screening program to test and treat for Helicobacter pylori infection: Cost-utility analysis by age, sex and ethnicity

BACKGROUND

The World Health Organization recommends all countries consider screening for H. pylori to prevent gastric cancer. We therefore aimed to estimate the cost-effectiveness of a H. pylori serology-based screening program in New Zealand, a country that includes population groups with relatively high gastric cancer rates.

METHODS

A Markov model was developed using life-tables and morbidity data from a national burden of disease study. The modelled screening program reduced the incidence of non-cardia gastric cancer attributable to H. pylori, if infection was identified by serology screening, and for the population expected to be reached by the screening program. A health system perspective was taken and detailed individual-level costing data was used.

RESULTS

For adults aged 25-69 years old, nation-wide screening for H. pylori was found to have an incremental cost of US$196 million (95% uncertainty interval [95% UI]: $182-$211 million) with health gains of 14,200 QALYs (95% UI: 5,100-26,300). Cost per QALY gained was US$16,500 ($7,600-$38,400) in the total population and 17% (6%-29%) of future gastric cancer cases could be averted with lifetime follow-up. A targeted screening program for Māori only (indigenous population), was more cost-effective at US$8,000 ($3,800-$18,500) per QALY.

CONCLUSIONS

This modeling study found that H. pylori screening was likely to be cost-effective in this high-income country, particularly for the indigenous population. While further research is needed to help clarify the precise benefits, costs and adverse effects of such screening programs, there seems a reasonable case for policy-makers to give pilot programs consideration, particularly for any population groups with relatively elevated rates of gastric cancer.

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.

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.

Helicobacter pylori and Gastrointestinal Malignancies

Helicobacter pylori infection is the principal trigger of gastric carcinogenesis and gastric cancer (GC) and remains the third leading cause of cancer-related death in both sexes worldwide. In a big Japanese study, the risk of developing GC in patients with peptic ulcer disease who received H. pylori eradication therapy and annual endoscopic surveillance for a mean of 9.9 years was significantly lower after successful eradication therapy compared to the group with persistent infection (0.21%/year and 0.45%/year, respectively, p = .049). According to a recent meta-analysis, H. pylori eradication is insufficient in GC risk reduction in subjects with advanced precancerous conditions (i.e., intestinal metaplasia and dysplasia). A microsimulation model suggested screening smokers over the age of 50 in the U.S. for serum pepsinogens. This would allow to detect advanced gastric atrophy with endoscopic follow-up of subjects testing positive as a cost-effective strategy to reduce GC mortality. In a Taiwanese study, the anti-H. pylori IgG-based test-and-treat program had lower incremental cost-effectiveness ratios than that with (13)C-urea breath test in both sexes to prevent GC whereas expected years of life lost for GC were higher and the incremental cost-effectiveness ratios of test-and-treat programs were more cost-effective in young adults (30-69 years old) than in elders (>70 years old). With respect to gastrointestinal malignancies other than GC, a meta-analysis confirmed the inverse association between H. pylori infection and esophageal adenocarcinoma. In a Finnish study, H. pylori seropositivity was associated with an increased risk of biliary tract cancers (multivariate adjusted OR 2.63; 95% CI: 1.08-6.37), another meta-analysis showed a slightly increased rate of pancreatic cancer in patients with CagA-negative strains (OR: 1.30; 95% CI: 1.02-1.65), whereas current data suggest that the association between H. pylori and colorectal neoplasms may be population dependent.

Viruses, Other Pathogenic Microorganisms and Esophageal Cancer

BACKGROUND

Esophageal cancer (EC) is the eighth most prevalent malignant tumor and the sixth leading cause of cancer mortality throughout the world. Despite the technical developments in diagnosis and treatment, the 5-year survival rate is still low. The etiology of EC remains poorly understood; multiple risk factors may be involved and account for the great variation in EC incidence in different geographic regions.

SUMMARY

Infection with carcinogenetic pathogens has been proposed as a risk factor for EC. This review explores the recent studies on the association of human papillomavirus (HPV), Epstein-Barr virus (EBV), Helicobacter pylori and esophageal bacterial biota with EC.

KEY MESSAGE

Among the above-mentioned pathogens, HPV most likely contributes to esophageal squamous cell carcinoma (ESCC) in high-risk populations. New techniques are being applied to studies on the role of infection in EC, which will inevitably bring novel ideas to the field in the near future.

PRACTICAL IMPLICATIONS

Multiple meta-analyses support the finding of a higher HPV detection rate in regions associated with high risk for ESCC compared to low-risk areas. A potential role of HPV in the rise of esophageal adenocarcinoma (EAC) was proposed recently. However, further studies are required before a firm conclusion can be drawn. Less work has been done in studying the association between EBV and ESCC, and the results are quite controversial. H. pylori infection is found to be inversely related to EC, which is probably due to the reduced incidence of gastroesophageal reflux disease. Analysis of the esophageal bacterial biota revealed distinct clusters of bacteria in normal and diseased esophagi. A type II microbiome rich in Gram-negative bacteria potentially contributes to EAC by inducing chronic inflammation. Novel findings from such studies as these may benefit public health by justifying anti-infection measures to prevent EC.