Helicobacter pylori eradication and metachronous gastric cancer after endoscopic mucosal resection of early gastric cancer

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

BACKGROUND & AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

[Guidelines for the diagnosis and treatment of Helicobacter pylori infection in Korea, 2013 revised edition]

Since the Korean College of Helicobacter and Upper Gastrointestinal Research has first developed the guideline for the diagnosis and treatment of Helicobacter pylori infection in 1998, the revised guideline was proposed in 2009 by the same group. Although the revised guideline was made by comprehensive review of previous articles and consensus of authoritative expert opinions, the evidence-based developmental process was not applied in the revision of the guideline. This new guideline has been revised especially in terms of changes in the indication and treatment of H. pylori infection in Korea, and developed by the adaptation process as evidence-based method; 6 guidelines were retrieved by systematic review and the Appraisal of Guidelines for Research and Evaluation (AGREE) II process, 21 statements were made with grading system and revised by modified Delphi method. After revision, 11 statements for the indication of test and treatment, 4 statements for the diagnosis and 4 statements for the treatment have been developed, respectively. The revised guideline has been reviewed by external experts before the official endorsement, and will be disseminated for usual clinical practice in Korea. Also, the scheduled update and revision of the guideline will be made periodically.

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.

Failure of Helicobacter pylori eradication and age are independent risk factors for recurrent neoplasia after endoscopic resection of early gastric cancer in 283 patients

BACKGROUND

Whether the incidence of metachronous gastric dysplasia and cancer could be decreased by eradication of Helicobacter pylori after endoscopic submucosal dissection (ESD) for early gastric cancer (EGC).

AIM

To compare the incidence of metachronous gastric lesion in the eradicated group and the persistent group. Second end point is to evaluate the risk factors for metachronous gastric lesions after ESD for EGC.

METHODS

In a single centre, between May 2007 and May 2010, the patients who had evidence of H. pylori infection at the time of ESD for EGC were included, and the follow-up data were analysed retrospectively.

RESULTS

We enrolled 283 patients who have shown H. pylori infection at the time of ESD for EGC. Successful eradication was achieved for 214 patients (75.6%) (Eradicated group), and 69 patients (24.4%) showed persistent H. pylori infection (Persistent group). Metachronous gastric lesions developed in 13 (18.8%) in the persistent group and 18 (8.4%) in the eradicated group (P = 0.016). In the ≥60-year-old group, the cumulative incidence of metachronous gastric cancer showed a significant increase (P = 0.012). Cumulative hazard ratio of subsequent gastric metachronous lesions differed between the eradication group and the persistent infection group (OR = 2.322, 95% CI = 1.136-4.744, P = 0.021), and ≥60 age at the time of endoscopic resection (OR = 2.803, 95% CI = 1.207-6.509, P = 0.016).

CONCLUSIONS

Both persistent H. pylori infection and old age (≥60) are independent risk factors for the increased incidence of metachronous gastric cancer.

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.

Long-term effect of Helicobacter pylori eradication on the development of metachronous gastric cancer after endoscopic resection of early gastric cancer

BACKGROUND

A prospective, randomized trial proved that Helicobacter pylori eradication significantly reduces the incidence of metachronous gastric cancer during a 3-year follow-up.

OBJECTIVE

To investigate the long-term effect of H pylori eradication on the incidence of metachronous gastric cancer after endoscopic resection of early gastric cancer.

DESIGN

Retrospective, multicenter study.

SETTING

Kyushu University Hospital and 6 other hospitals in Fukuoka Prefecture, Japan.

PATIENTS AND INTERVENTIONS

Follow-up data for 268 H pylori-positive patients who had undergone endoscopic resection of early gastric cancer were retrospectively investigated. A total of 177 patients underwent successful H pylori eradication (eradicated group), whereas 91 had persistent H pylori infection (persistent group).

MAIN OUTCOME MEASUREMENTS

The incidence of metachronous gastric cancer was compared in these 2 groups.

RESULTS

When the follow-up period was censored at 5 years, the incidence rate in the eradicated group was lower than that observed in the persistent group (P = .007). During the overall follow-up period ranging from 1.1 to 11.1 years (median 3.0 years), metachronous gastric cancer developed in 13 patients (14.3%) in the persistent group and in 15 patients (8.5%) in the eradicated group (P = .262, log-rank test). Based on a multivariate logistic regression analysis, baseline severe mucosal atrophy and a follow-up of more than 5 years were found to be independent risk factors for the development of metachronous gastric cancer.

LIMITATIONS

Retrospective study.

CONCLUSIONS

H pylori eradication does not reduce the incidence of metachronous gastric cancer. H pylori eradication should be performed before the progression of gastric mucosal atrophy.

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.

Helicobacter pylori and clinical aspects of gastric cancer

In spite of important new insights into the basic mechanisms of gastric carcinogenesis, progress in the management of gastric cancer has been modest. Some modifications in the chemotherapies used for palliation and strategies for downstaging of the disease prior to surgical intervention are noteworthy. The positive experience with endoscopic mucosal resection (EMR) and submucosal dissection (ESD) for treatment of early gastric cancer has been confirmed and extended. The procedure-related morbidity and post-interventional quality of life is clearly favorable compared to open surgical resection in well-selected patients. New data on Helicobacter pylori revealed that eradication after endoscopic resection of early gastric cancer significantly reduces the incidence of recurrent and metachronous gastric neoplasias. It can further improve healing rates of treatment induced gastric ulcers. Eradication therapy therefore remains the best target for prevention of the disease. Critical is the "point of no return" when mucosal alterations (i.e. intestinal metaplasia, glandular atrophy) are no longer reversible. A population-based screen-and-eradicate strategy for H. pylori infection can at present only be recommended in high incidence regions.

Does the eradication of Helicobacter pylori delay the diagnosis of gastric cancer?

OBJECTIVE

To assess the frequency of gastric cancer patients having received eradication treatment of Helicobacter pylori, and whether this treatment has any influence on the delay in the diagnosis or the stage of the tumours at the time of the operation.

MATERIAL AND METHODS

A total of 119 consecutive patients with gastric cancer were interviewed preoperatively between 2001 and 2003 at the Department of Surgery, Helsinki University Central Hospital. Abdominal symptoms, previous endoscopies, previous H. pylori testing and eradication therapies were recorded. RESULTS. Of these patients, 112 (94%) had abdominal symptoms before the cancer diagnosis, and in 110 patients (92%) these symptoms were alarming or had changed before the cancer diagnosis. Thirty-five patients (29%) had received H. pylori eradication therapy prior to the diagnosis of gastric cancer (15 after onset or change in symptoms, 10 more than 5 years prior to the cancer diagnosis). The median duration of alarm, new or changed symptoms was longer among patients with H. pylori eradication therapy after the onset or change in their symptoms as compared to other patients (12.0 versus 4.5 months, p=0.001). However, there was no difference in the tumour stages at time of the operation between the eradication and no eradication groups. A previous gastroscopy within 2 years prior to the cancer diagnosis was performed in 17 (14%) patients. Diffuse-type cancers were missed significantly more often in endoscopies than cancers of intestinal type.

CONCLUSION

Previous H. pylori eradication may delay the detection of gastric cancer if it is given during symptoms caused by tumour.

Normalization of pH level and gastric mucosa after eradication of H. pylori in the remnant stomach

BACKGROUND

The Updated Sydney System (USS) is used to evaluate chronic gastritis and chronic atrophic gastritis (CAG) due to H. pylori infection. Here, we investigated USS scores and gastric juice pH levels in H. pylori infection-positive or -eradicated patients with remnant stomach after surgery.

METHODS

Gastric juice pH levels were measured using pH test-tape in 197 patients (112 H. pylori-positive and 85 H. pylori-negative after eradication) who had undergone distal gastrectomy and conventional H. pylori eradication therapy.

RESULTS

In H. pylori infection-positive remnant stomach cases, gastric juice pH showed a reverse correlation with pepsinogen I/II ratio, and H. pylori infection-negative patients following eradication showed associations with the degree of atrophy and intestinal metaplasia at both the anastomosis and in the corpus. Further, pH levels in these patients were normalized time depending after the eradication in the remnant stomach.

CONCLUSIONS

Eradication therapy for the remnant stomach contributes to the possible improvement of stomach conditions by controlling the pH level of gastric juice. This effect will be protective against the risk of secondary stomach carcinogenesis in the remnant stomach.

Effect of eradication of Helicobacter pylori on incidence of metachronous gastric carcinoma after endoscopic resection of early gastric cancer: an open-label, randomised controlled trial

BACKGROUND

The relation between Helicobacter pylori infection and gastric cancer has been proven in epidemiological studies and animal experiments. Our aim was to investigate the prophylactic effect of H pylori eradication on the development of metachronous gastric carcinoma after endoscopic resection for early gastric cancer.

METHODS

In this multi-centre, open-label, randomised controlled trial, 544 patients with early gastric cancer, either newly diagnosed and planning to have endoscopic treatment or in post-resection follow-up after endoscopic treatment, were randomly assigned to receive an H pylori eradication regimen (n=272) or control (n=272). Randomisation was done by a computer-generated randomisation list and was stratified by whether the patient was newly diagnosed or post-resection. Patients in the eradication group received lansoprazole 30 mg twice daily, amoxicillin 750 mg twice daily, and clarithromycin 200 mg twice daily for a week; those in the control group received standard care, but no treatment for H pylori. Patients were examined endoscopically at 6, 12, 24, and 36 months after allocation. The primary endpoint was diagnosis of new carcinoma at another site in the stomach. Analyses were by intention to treat. This trial is registered with the UMIN Clinical Trials Registry, number UMIN000001169.

FINDINGS

At 3-year follow-up, metachronous gastric carcinoma had developed in nine patients in the eradication group and 24 in the control group. In the full intention-to-treat population, including all patients irrespective of length of follow-up (272 patients in each group), the odds ratio for metachronous gastric carcinoma was 0.353 (95% CI 0.161-0.775; p=0.009); in the modified intention-to-treat population, including patients with at least one post-randomisation assessment of tumour status and adjusting for loss to follow-up (255 patients in the eradication group, 250 in the control group), the hazard ratio for metachronous gastric carcinoma was 0.339 (95% CI 0.157-0.729; p=0.003). In the eradication group, 19 (7%) patients had diarrhoea and 32 (12%) had soft stools.

INTERPRETATION

Prophylactic eradication of H pylori after endoscopic resection of early gastric cancer should be used to prevent the development of metachronous gastric carcinoma.

FUNDING

Hiroshima Cancer Seminar Foundation.

The association between Helicobacter pylori infection and early gastric cancer: a meta-analysis

OBJECTIVE

Helicobacter pylori (H. pylori) is recognized as a definite carcinogen for gastric cancer. The prevalence of H. pylori infection in patients with gastric cancer varies widely among studies and no meta-analysis on the prevalence of H. pylori infection in early gastric cancer (EGC) has been performed. We aimed to review systematically the relationship between H. pylori infection and EGC, and different types of EGC.

METHODS

Observational studies reporting raw data on the prevalence of H. pylori infection in EGC and controls, or comparing different types of EGC, conducted in adult populations, and published in the English language were identified through MEDLINE and EMBASE up to June 2006.

RESULTS

Of 87 relevant studies, 19 case-control studies met inclusion criteria. Of these, 15 studies compared EGC (N = 2,722) and non-neoplasm controls (N = 13,976) or advanced gastric cancer (AGC) (N = 1,130), 9 studies compared the intestinal-type (I-EGC) and diffuse-type (D-EGC) of EGC, and 2 studies compared the differentiated-type (DF-EGC) and undifferentiated-type (UDF-EGC) of EGC and were included in the meta-analysis. The prevalence of H. pylori infection was significantly higher in patients with EGC (87.3%) than in non-neoplasm controls (61.4%) (OR 3.38, 95% CI 2.15-5.33, P < 0.00001). However, significant heterogeneity was seen (P < 0.00001). Four large sample (N > or = 100) studies (N = 2,060) may result in the heterogeneity, but the conclusion remained unchanged when sensitivity analysis was made with the other 11 homogeneous small sample studies alone, in which the prevalence of H. pylori infection was significantly higher in EGC (N = 662) than that in controls (N = 5,898) (87.8%vs 68.6%, P < 0.00001), and the odds ratio (OR 3.28, 95% CI 2.34-4.61) was similar to the large sample studies alone (OR 3.40, 95% CI 1.14-10.12). The prevalence of H. pylori infection in EGC was significantly higher than in AGC (6 studies) (OR 2.13, 95% CI 1.75-2.59) and 16-fold higher in patients with DF-EGC than in those with UDF-EGC (OR 16.53, 95% CI 2.64-103.43). No significant difference in the prevalence of H. pylori infection was seen between the patients with I-EGC and D-EGC types (OR 0.75, 95% CI 0.26-2.18).

CONCLUSIONS

This study indicates that H. pylori infection is strongly associated with early gastric cancer when compared with non-neoplasm controls or advanced gastric cancer. To determine more accurately the effect size of H. pylori in EGC, age-matched normal controls or adjusting for age in the analysis should be considered in H. pylori-related gastric cancer case-control studies.

Eradication of Helicobacter pylori for primary gastric cancer and secondary gastric cancer after endoscopic mucosal resection

Because most gastric cancers develop from a background of Helicobacter pylori-infected gastric mucosa, H. pylori plays an important role in gastric carcinogenesis. Therefore, eradication of H. pylori may inhibit the incidence of gastric cancers. In experimental studies, H. pylori eradication has proved to act as a prophylaxis against gastric cancer. However, the results of recent randomized controlled studies are absolutely contradictory. In Japan, mucosal gastric cancer is usually resected by endoscopic treatment. As only a small part of the gastric mucosa is resected, secondary gastric cancer after endoscopic resection of the primary gastric cancer often develops at another site in the stomach. A nonrandomized Japanese study involving 132 early gastric cancer patients reported that eradication of H. pylori after endoscopic resection tended to reduce the development of secondary gastric cancer. Also, a retrospective multicenter survey indicated that the incidence rate of secondary gastric cancer in H. pylori-eradicated patients was about one-third that among patients in the non eradication group. We conducted a large-scale multicenter randomized trial to confirm the effect of H. pylori eradication on secondary and residual gastric cancer after endoscopic resection. This study was begun in 2003 and is ongoing at present. Diagnosis of a new carcinoma at another site of the stomach is defined as the primary end point, and recurrence of tumors at the resection site as a secondary end point. A total of 542 subjects have been enrolled in the study. This study will have the statistical power to demonstrate whether H. pylori eradication decreases the incidence and recurrence of gastric cancer.