Helicobacter pylori status and risks of metachronous recurrence after endoscopic resection of early gastric cancer: a systematic review and meta-analysis

Optimal Surveillance of Metachronous Gastric Lesion after Endoscopic Resection of Early Gastric Cancer

Endoscopic resection (ER)-a minimal invasive procedure, compared to surgical gastrectomy, with the advantage of preserving the entire stomach and maintaining the patient's quality of life-is a widely used curative treatment for early gastric cancers (EGCs). Despite its advantages, such as the preservation of the whole stomach, a large area of the gastric mucosa with histologic changes such as atrophy and intestinal metaplasia remains after ER, and so does the risk of metachronous gastric cancers (MGCs). Therefore, regular surveillance endoscopy after curative ER of EGCs is important so that MGCs are detected early and so minimally invasive ER remains a treatment option. To date, the optimal interval for surveillance endoscopy after curative ER of EGCs has not been established. Therefore, this review summarizes the results of the published studies on this topic with the aim of establishing the optimal surveillance interval for early identification of MGCs. Based on my review, the median timing of MGC occurrence is within 3 years, and reports suggest biannual endoscopy during the first 3 years; however, the evidence suggests that individual patient characteristics may influence the risk of MGCs. Therefore, stratified endoscopic strategies for surveillance based on patient characteristics, such as age, family history of gastric cancer, synchronous gastric lesions, and corpus intestinal metaplasia, should be applied.

Helicobacter pylori eradication following endoscopic resection might prevent metachronous gastric cancer: a systematic review and meta-analysis of studies from Japan and Korea

OBJECTIVES

A systematic review and meta-analysis was performed to evaluate the preventive effectiveness of Helicobacter pylori eradication against metachronous gastric cancer (MGC) or dysplasia following endoscopic resection (ER) for early gastric cancer (EGC) or dysplasia.

METHODS

PubMed, Cochrane Library, MEDLINE, and EMBASE were searched until 31 October 2023, and randomized controlled trials or cohort studies were peer-reviewed. The incidence of metachronous gastric lesions (MGLs) including MGC or dysplasia was compared between Helicobacter pylori persistent and negative groups, eradicated and negative groups, and eradicated and persistent groups.

RESULTS

Totally, 21 eligible studies including 82,256 observations were analyzed. Compared to those never infected, Helicobacter pylori persistent group (RR = 1.58, 95% CI = 0.98-2.53) trended to have a higher risk of MGLs and significantly in partial subgroups, while the post-ER eradicated group (RR = 0.79, 95% CI = 0.43-1.45) did not increase the risk of MGLs. Moreover, successful post-ER eradication could significantly decrease the risk of MGLs (RR = 0.54, 95% CI = 0.44-0.65) compared to those persistently infected. Sensitivity analysis obtained generally consistent results, and no significant publication bias was found.

CONCLUSION

The persistent Helicobacter pylori infection trends to increase the post-ER incidence of MGC or dysplasia, but post-ER eradication can decrease the risk correspondingly. Post-ER screening and eradication of Helicobacter pylori have preventive effectiveness on MGC, and the protocol should be recommended to all the post-ER patients.Systematic review registration: The PROSPERO registration identification was CRD42024512101.

Maintaining H. pylori Negativity After Eradication Can Consolidate Its Benefit in Gastric Cancer Prevention: A Meta-Analysis

INTRODUCTION

Several studies have reported the role of Helicobacter pylori eradication in gastric cancer (GC) prevention. However, for individuals with unsatisfactory management of their H. pylori infection status after eradication, the risk of GC remains unclear.

METHODS

An exhaustive search strategy of the incidence of GC (including primary gastric cancer and metachronous gastric cancer) incidence in patients with unsuccessful eradication or H. pylori reinfection was implemented in the PubMed, Embase, Cochrane Library, and Web of Science. The hazard ratios (HRs) and cumulative incidence of total GC in patients with failed eradication or H. pylori reinfection (FE-Hp (+)) group were compared with that in patients with successful eradication and no H. pylori reinfection (SE-Hp (-)) group and patients with noneradication (NE) group.

RESULTS

Seven eligible studies (including 8,767 patients with H. pylori infection) were identified. In the FE-Hp (+) group, the total GC risk was 1.86-fold of that in the SE-Hp (-) group (HR = 1.86, 95% confidence interval [CI]: 1.14-3.04, P = 0.013). The total GC risk in the NE group was also higher than that in the FE-Hp (+) group (HR = 1.98, 95% CI: 1.11-3.52, P = 0.002). On further analysis with different end points showed that the pooled GC risk increased over time (5-year follow-up: HR = 2.92, 1.34-6.34; 10-year follow-up: HR = 4.04, 2.56-6.37).

DISCUSSION

Compared with the SE-Hp (-) group, the FE-Hp (+) group had a higher risk of gastric carcinoma. Long-term monitoring of H. pylori infection status could consolidate the benefit of eradicating H. pylori for preventing GC prevention in patients after eradication.

Characteristic endoscopic findings in Helicobacter pylori diagnosis in clinical practice

INTRODUCTION

Helicobacter pylori is a major risk factor for gastric cancer. In addition to eradication therapy, early-phase detection of gastric cancer through screening programs using high-vision endoscopy is also widely known to reduce mortality. Although European and US guidelines recommend evaluation of atrophy and intestinal metaplasia by high-vision endoscopy and pathological findings, the guideline used in Japan - the Kyoto classification of gastritis - is based on endoscopic evaluation, and recommends the grading of risk factors. This system requires classification into three endoscopic groups: H. pylori-negative, previous H. pylori infection (inactive gastritis), and current H. pylori infection (active gastritis). Major endoscopic findings in active gastritis are diffuse redness, enlarged folds, nodularity, mucosal swelling, and sticky mucus, while those in H pylori-related gastritis - irrespective of active or inactive status - are atrophy, intestinal metaplasia, and xanthoma.

AREAS COVERED

This review describes the endoscopic characteristics of current H. pylori infection, and how characteristic endoscopic findings should be evaluated.

EXPERT OPINION

Although the correct evaluation of endoscopic findings related to H. pylori remains necessary, if findings of possible infection are observed, it is important to diagnose infection by detection methods with high sensitivity and specificity, including the stool antigen test and urea breath test.

Interaction between intestinal flora and gastric cancer in tumor microenvironment

Gastric Cancer (GC) is a prevalent malignancy globally and is the third leading cause of cancer-related deaths. Recent researches focused on the correlation between intestinal flora and GC. Studies indicate that bacteria can influence the development of gastrointestinal tumors by releasing bacterial extracellular vesicles (BEVs). The Tumor microenvironment (TME) plays an important role in tumor survival, with the interaction between intestinal flora, BEVs, and TME directly impacting tumor progression. Moreover, recent studies have demonstrated that intestinal microflora and BEVs can modify TME to enhance the effectiveness of antitumor drugs. This review article provides an overview and comparison of the biological targets through which the intestinal microbiome regulates TME, laying the groundwork for potential applications in tumor diagnosis, treatment, and prognosis.

Helicobacter pylori Treatment and Gastric Cancer Risk After Endoscopic Resection of Dysplasia: A Nationwide Cohort Study

BACKGROUND & AIMS

The study investigated the association between Helicobacter pylori treatment and the risk of gastric cancer after endoscopic resection of gastric dysplasia.

METHODS

Patients who received endoscopic resection for gastric dysplasia between 2010 and 2020 from Korean nationwide insurance data were included. We verified the occurrence of new-onset gastric cancer and metachronous gastric neoplasm, which encompasses both cancer and dysplasia, >1 year after the index endoscopic resection. Newly diagnosed gastric cancer ≥3 years and ≥5 years was regarded as late-onset gastric cancer. A multivariable Cox regression model with H pylori treatment status as a time-dependent covariate was used to determine the risk of gastric cancer and metachronous gastric neoplasms.

RESULTS

Gastric dysplasia in 69,722 patients was treated with endoscopy, and 49.5% were administered H pylori therapy. During the median 5.6 years of follow-up, gastric cancer developed in 2406 patients and metachronous gastric neoplasms developed in 3342 patients. Receiving H pylori therapy was closely related to lower gastric cancer risk (adjusted hazard ratio [aHR], 0.88; 95% confidence interval [CI], 0.80-0.96). H pylori treatment also significantly decreased metachronous gastric neoplasm development (aHR, 0.76; 95% CI, 0.70-0.82). Furthermore, H pylori therapy showed a prominent protective effect for late-onset gastric cancer development at ≥3 years (aHR, 0.84; 95% CI, 0.75-0.94) and ≥5 years (aHR, 0.80; 95% CI, 0.68-0.95).

CONCLUSIONS

In this nationwide cohort, H pylori therapy after endoscopic resection of gastric dysplasia was associated with a reduced risk of gastric cancer and metachronous gastric neoplasm occurrence.

Curative criteria for endoscopic treatment of gastric cancer

Endoscopic treatment, particularly endoscopic submucosal dissection, has become the primary treatment for early gastric cancer. A comprehensive optical assessment, including white light endoscopy, image-enhanced endoscopy, and magnification, are the cornerstones for clinical staging and determining the resectability of lesions. This paper discusses factors that influence the indication for endoscopic resection and the likelihood of achieving a curative resection. Our review stresses the critical need for interpreting the histopathological report in accordance with clinical guidelines and the imperative of tailoring decisions based on the patients' and lesions' characteristics and preferences. Moreover, we offer guidance on managing complex scenarios, such as those involving non-curative resection. Finally, we identify future research avenues, including the role of artificial intelligence in estimating the depth of invasion and the urgent need to refine predictive scores for lymph node metastasis and metachronous lesions.

Effect of Helicobacter pylori eradication on gastric precancerous lesions: A systematic review and meta-analysis

BACKGROUND

The question of whether eradication of Helicobacter pylori (Hp) can reverse gastric precancerous lesions, including intestinal metaplasia, remains uncertain, leading to ongoing debate. Therefore, a meta-analysis was performed to evaluate the effect of Hp eradication on gastric precancerous lesions.

MATERIALS AND METHODS

PubMed, Embase, Cochrane Library, Web of Science, Scopus database, and ClinicalTrials.gov were systematically searched from inception to April 2023 for studies that explored the impact of Hp eradication on gastric precancerous lesions. Risk ratios (RRs) and their 95% confidence intervals (95% CIs) were selected as the effect size. We used the random-effects model to assess pooled data. We also performed quality assessments, subgroup analyses, and sensitivity analyses.

RESULTS

Fifteen studies were included. Compared with placebo, Hp eradication could significantly prevent the progression of gastric precancerous lesions (RR = 0.87, 95% CI: 0.81-0.94, p < 0.01) and reverse them (RR = 1.32, 95% CI: 1.17-1.50, p < 0.01). Then, specific precancerous lesions were further explored. The progression of intestinal metaplasia was significantly prevented by Hp eradication compared to placebo or no treatment (RR = 0.80, 95% CI: 0.69-0.94, p < 0.01). Moreover, compared with placebo or no treatment, Hp eradication also improved chronic atrophic gastritis (RR = 1.84, 95% CI: 1.30-2.61, p < 0.01) and intestinal metaplasia (RR = 1.41, 95% CI: 1.15-1.73, p < 0.01). However, in terms of preventing dysplasia progression (RR = 0.86, 95% CI: 0.37-2.00) and improving dysplasia (RR = 0.89, 95% CI: 0.47-1.70), Hp eradication had no advantage compared to placebo or no treatment.

CONCLUSIONS

Hp eradication therapy could prevent the progression of gastric precancerous lesions and reverse them. Notably, intestinal metaplasia can be reversed, but this may only be appropriate for patients with epigenetic alterations and milder lesions.

Endoscopic Resection of Early Gastric Cancer and Pre-Malignant Gastric Lesions

Early gastric cancer comprises gastric malignancies that are confined to the mucosa or submucosa, irrespective of lymph node metastasis. Endoscopic resection is currently pivotal for the management of such early lesions, and it is the recommended treatment for tumors presenting a very low risk of lymph node metastasis. In general, these lesions consist of two groups of differentiated mucosal adenocarcinomas: non-ulcerated lesions (regardless of their size) and small ulcerated lesions. Endoscopic submucosal dissection is the technique of choice in most cases. This procedure has high rates of complete histological resection while maintaining gastric anatomy and its functions, resulting in fewer adverse events than surgery and having a lesser impact on patient-reported quality of life. Nonetheless, approximately 20% of resected lesions do not fulfill curative criteria and demand further treatment, highlighting the importance of patient selection. Additionally, the preservation of the stomach results in a moderate risk of metachronous lesions, which underlines the need for surveillance. We review the current evidence regarding the endoscopic treatment of early gastric cancer, including the short-and long-term results and management after resection.

Statistical proof of Helicobacter pylori eradication in preventing metachronous gastric cancer after endoscopic resection in an East Asian population

We conducted a comprehensive literature review and meta-analysis study on the efficacy of Helicobacter pylori (H. pylori) eradication in preventing metachronous gastric cancer after endoscopic resection among an East Asian population. Our results showed that the eradication of this pathogen significantly reduced the risk of susceptibility to metachronous gastric cancer in these patients. However, based on the available evidence, several factors such as increasing age, severe atrophy in the corpus and antrum, and intestinal metaplasia all may increase the risk of metachronous gastric cancer in H. pylori eradicated patients.

Clinical outcomes of metachronous recurrence of gastric epithelial neoplasia based on Helicobacter pylori infection status and microsatellite stability

BACKGROUND/AIMS

Helicobacter pylori eradication may prevent the recurrence of gastric epithelial neoplasia after endoscopic treatment. However, H. pylori eradication therapy is unlikely to prevent gastric cancer. This study determined the longterm results and clinical outcomes of patients with gastric epithelial neoplasia based on H. pylori infection status and microsatellite stability (MSS).

METHODS

Patients diagnosed with gastric epithelial neoplasia who underwent an endoscopic mucosal resection or submucosal dissection between 2004 and 2010 were included in this retrospective study. During the follow-up period (range, 4 to 14 years), disease recurrence was monitored, and tissue examinations were conducted for seven sets of microsatellite loci initially linked to the tumour suppressor gene locus. When H. pylori infection was identified, patients underwent eradication therapy.

RESULTS

The patients (n = 120) were divided into three groups: H. pylori-negative with MSS, H. pylori-positive with MSS, and microsatellite instability (MSI). After H. pylori eradication, the rate of metachronous recurrence was significantly different in the MSI (28.2%) and MSS groups (3.7%, p < 0.01). The mean duration of recurrence was 77 months (range, 24 to 139) in the MSI group. There was no recurrence after eradication therapy in patients who were positive for H. pylori in the MSS group.

CONCLUSION

H. pylori eradication could help prevent gastric cancer recurrence in patients with stable microsatellite loci. Careful, long-term monitoring is required in patients with unstable microsatellite loci.

From part to whole, operative link on to endoscopic grading of gastric intestinal metaplasia, pathology to endoscopy: gastric intestinal metaplasia graded by endoscopy

Objective: To conduct a systematic review and meta-analysis on the prediction of severity of gastric intestinal metaplasia (GIM) in localized and entire gastric mucosa using endoscopy. Methods: The authors searched Web of Science, PubMed, Embase and Cochrane Central Register of Controlled Trials and performed systematic searches on endoscopic grading of GIM of the entire stomach using Meta-DiSc and Stata. Results: Sensitivity and specificity for the stratified prediction of overall GIM were 0.91 (95% CI: 0.85-0.95) and 0.91 (95% CI: 0.88-0.93), respectively. Sensitivity in predicting the different grades of GIM was higher in operative link on GIM assessment grades 0, III and IV but lower in grades I and II. Conclusion: Digital chromoendoscopy is well suited to predicting the severity of localized and overall GIM.

Long-Term Outcome of Gastric Mild-Moderate Dysplasia: A Real-World Clinical Experience

BACKGROUND & AIMS

The natural course of gastric mild-moderate dysplasia in a country with high incidence of gastric cancer (GC) is relatively unknown. We aimed to determine the long-term cumulative incidence of and risk factors for advanced neoplasia in patients with gastric dysplasia.

METHODS

This was a single-center observational study including all consecutive patients diagnosed with gastric mild-moderate dysplasia between 2000 and 2017. Follow-up data were collected until December 2019. We determined the cumulative incidence of advanced neoplasia and identified risk factors with Cox regression.

RESULTS

A total of 3489 consecutive participants were followed for a median of 4.19 years from initial mild-moderate dysplasia diagnosis. The median surveillance interval between index endoscopy and next follow-up endoscopy was 1.08 years, and more than half of patients had at least 3 surveillance gastroscopies. During the study period, the majority of participants did not show disease progression, either with dysplasia not detected (51.4%) or with persistent dysplasia (46.1%). There were 88 (2.9%) patients (5.13 per 1000 patient-years) who progressed to advanced neoplasia within a median of 4.3 years. The annual incidence of advanced neoplasia and GC were 0.43% and 0.26%, respectively, within 5 years of mild-moderate dysplasia diagnosis. Increasing age, male sex, moderate dysplasia, dysplasia detected in fundus or cardia at index endoscopy, and persistent Helicobacter pylori infection during follow-up were independent risk factors for developing advanced neoplasia.

CONCLUSIONS

Even in a country with high incidence of GC, the majority of patients with gastric mild-moderate dysplasia did not experience disease progression in the long term. Intensified surveillance during the first 5 years after mild-moderate dysplasia detection is suggested.

Comparative molecular subtypes of index and metachronous gastric adenocarcinomas: a study of 42 Korean patients

To date, there have been no studies comparing the molecular subtypes of Index gastric cancers (IGCs) and metachronous gastric cancers (MGCs). We evaluated a cohort of 42 patients with 43 IGCs and 45 MGCs. Molecular subtyping was performed by immunohistochemistry of mismatch repair (MMR) proteins, E-cadherin, p53, and Epstein-Barr virus- (EBV-) in situ hybridization (ISH). Gastric adenocarcinomas were classified into 5 subtypes: EBV-associated, MMR deficient (MMRD), E-cadherin aberrant, p53-aberrant [p53(+)], and p53 non-aberrant [p53(neg)]. All IGCs had been successfully treated by either surgery (19%) or endoscopic resection (81%). The mean interval between IGCs and MGCs was 85 months. Among the IGCs, EBV-associated, MMRD, E-cadherin-aberrant, p53(+), and p53(neg) molecular subtypes represented 2 (5%), 4 (9%), 2 (5%), 21 (49%), and 14 (32%) of the cases, respectively. Two cases had concomitant p53(+) and aberrant E-cadherin molecular subtypes. Among metachronous cancers, EBV-associated, MMRD, E-cadherin-aberrant, p53(+), and p53(neg) molecular subtypes represented 3 (7%), 11 (24%), 0 (0%), 22 (49%), and 9 (20%) cases. Concomitant p53(+) was observed in 1 EBV-associated and 2 MMRD MGCs. Although, there was no significant difference in the frequency of most molecular subtypes in IGCs and MGCs, the number of MMRD gastric cancers more than doubled in the MGC group. Half of the MGCs had a divergent molecular subtype compared to that of the IGCs. Notably, the interval between the development of IGCs and MGCs was significantly longer in patients with divergent molecular subtypes (P = 0.010). All 4 patients with MMRD IGC developed MMRD MGCs. Although the concept of mucosal field cancerization may explain the matching molecular subtypes in early-developing MGCs, the presence of divergent subtypes in late-occurring MGCs suggests a shift in the carcinogenic mechanism affecting the residual mucosa possibly related to Helicobacter pylori eradication.

Long-term changes in the gut microbiota after triple therapy, sequential therapy, bismuth quadruple therapy and concomitant therapy for Helicobacter pylori eradication in Chinese children

BACKGROUND

We previously reported that the administration of 14-day standard triple therapy (TT), sequential therapy (ST), bismuth-based quadruple therapy (BT), and concomitant therapy (CT) as the first-line therapy for Helicobacter pylori infection in Chinese children achieved eradication rates of 74.1%, 69.5%, 89.8%, and 84.6%, respectively. In this follow-up study, we further evaluated the short- and long-term effects of the four regimens on the gut microbiota in these children.

METHODS

We prospectively recruited treatment-naïve children with H. pylori infection. Fecal samples were collected at week 0, 2, 6, and 52, and alterations in the gut microbiota were analyzed by 16S rRNA gene sequencing.

RESULTS

Sixty-three patients participated in this study (16 with TT, 15 with ST, 16 with BT and 16 with CT). At week 2, the alpha diversity (Shannon and Chao 1 index) was significantly reduced in the TT (p = 0.008, p < 0.001), ST (p < 0.001, p < 0.001), BT (p < 0.001, p < 0.001) and CT groups (p < 0.001, p < 0.001). Some changes persisted in the ST, BT, and CT groups at week 6, and all were restored (expect p = 0.02 with Chao 1 index in the CT group) at week 52. The beta diversity was significantly changed in the BT (p = 0.001) and CT groups (p = 0.001) 2 weeks post-eradication and restored 1 year after therapy. Immediately after therapy, the relative abundance of Proteobacteria was strikingly increased in the ST (p = 0.005), BT (p < 0.001) and CT groups (p < 0.001), and the genus-level analysis showed that the abundances of 23.1%, 43.3%, 78.6%, and 78% of the bacterial genera in the TT, ST, BT, and CT groups were significantly changed. All these changes returned to almost the pre-eradication level 1 year post-eradication.

CONCLUSION

Eradication of H. pylori infection can lead to transient dysbiosis of gut microbiota, and these changes almost recovered 1 year post-eradication, which indicates the long-term safety of H. pylori therapy.

Effects of Helicobacter pylori eradication on gastric cancer incidence in the Japanese population: a systematic evidence review

BACKGROUND

In Japan, there are ongoing efforts to shift the gastric cancer prevention and control policy priorities from barium-based screening to Helicobacter pylori (H. pylori)-oriented primary prevention. A comprehensive summary of the evidence regarding the effects of H. pylori eradication on the risk of gastric cancer could inform policy decisions.

METHODS

We conducted a systematic review and meta-analysis of published studies evaluating the effectiveness of H. pylori eradication for the prevention of gastric cancer in otherwise healthy individuals (primary prevention) and early gastric cancer patients (tertiary prevention).

RESULTS

In total, 19 studies were included. Three moderate-quality observational cohort studies showed that H. pylori eradication may be associated with a decreased risk of gastric cancer in healthy asymptomatic Japanese people. There is moderate certainty regarding the effectiveness of H. pylori eradication in patients with gastrointestinal diseases, such as peptic ulcers. A meta-analysis of 10 observational studies with otherwise healthy individuals (mainly peptic ulcer patients) yielded an overall odds ratio of 0.34 (95% CI: 0.25-0.46). Regarding tertiary prevention, the overall odds ratio for developing metachronous gastric cancer was 0.42 (95% CI: 0.35-0.51) in the eradication group in a meta-analysis of nine studies involving early gastric cancer patients who underwent endoscopic resection.

CONCLUSION

H. pylori eradication is effective in preventing gastric cancer in the Japanese population, regardless of symptoms. Well-designed, large cohort studies are warranted to determine the long-term efficacy and safety of H. pylori eradication in the context of reducing the gastric cancer burden through population-based screening and treatment.

Preventing Metachronous Gastric Cancer after the Endoscopic Resection of Gastric Epithelial Neoplasia: Roles of Helicobacter pylori Eradication and Aspirin

Whether Helicobacter pylori eradication actually reduces the risk of metachronous gastric cancer (MGC) development remains a controversial question. In this review, we addressed this topic by reviewing the results of clinical investigations and molecular pathological analyses of the roles of H. pylori eradication and aspirin administration in the prevention of MGC. In regard to the clinical studies, the results of meta-analyses and randomized control trials differ from those of retrospective studies: the former trials show that H. pylori eradication has a preventive effect on MGC, while the latter studies do not. This discrepancy may be at least partly attributable to differences in the follow-up periods: H. pylori eradication is more likely to prevent MGC over a long-term follow-up period (≥5 years) than over a short-term follow-up period. In addition, many studies have shown that aspirin may have an additive effect on MGC-risk reduction after H. pylori eradication has been achieved. Both H. pylori eradication and aspirin use induce molecular alterations in the atrophic gastritis mucosa but not in the intestinal metaplasia. Unfortunately, the molecular pathological analyses of these interventions have been limited by short follow-up periods. Therefore, a long-term prospective cohort is needed to clarify the changes in molecular events caused by these interventions.

Clinical Outcomes of Metachronous Gastric Cancer after Endoscopic Resection for Early Gastric Cancer

Background/Aims

Patients treated with endoscopic submucosal dissection (ESD) for early gastric cancer (EGC) are at risk of developing metachronous gastric cancer (MGC). The aim of this study was to evaluate the clinical outcomes of MGC after ESD for EGC between the re-ESD and surgery groups.

Methods

In total, data from 1,510 patients who underwent ESD for EGC from January 2005 to May 2014 were retrospectively reviewed, and data from 112 patients with MGC were analyzed according to the type of treatment, namely, re-ESD and surgery. The clinicopathological factors affecting the subsequent treatment and outcomes of MGC were evaluated.

Results

The median duration to the development of MGC was 47 months. In multivariate analysis, lower body mass index (BMI) (p=0.037) and multiplicity (p=0.014) of index cases were significantly associated with subsequent surgery for MGC. In cases of MGC, a diffuse or mixed-type Lauren classification (p=0.009), the depth of tumor mucosal invasion (p=0.001), and an upper stomach location (p=0.049) were associated with surgery. Overall survival was significantly shorter in the surgery group than in the re-ESD group after treatment for MGC (log-rank test, p=0.01).

Conclusions

Lower BMI and multiplicity of index cancers were significantly associated with the surgical resection of MGC. Close follow-up is needed to minimize additional treatment for cases at high risk of advanced MGC after ESD for EGC.

Long-term persistence of gastric dysbiosis after eradication of Helicobacter pylori in patients who underwent endoscopic submucosal dissection for early gastric cancer

BACKGROUND

Gastric microbiome, other than Helicobacter pylori, plays a role in the tumorigenesis of gastric cancer (GC). Patients who undergo endoscopic submucosal dissection for early GC have a high risk of developing metachronous GC even after successful eradication of H. pylori. Thus, we investigated the microbial profiles and associated changes in such patients after the eradication of H. pylori.

METHODS

A total of 19 H. pylori-infected patients with early GC who were or to be treated by endoscopic resection, with paired biopsy samples at pre- and post-eradication therapy, were retrospectively enrolled. Ten H. pylori-negative patients were enrolled as controls. Biopsy samples were analyzed using 16S rRNA sequencing.

RESULTS

H. pylori-positive patients exhibited low richness and evenness of bacteria with the deletion of several genera, including Blautia, Ralstonia, Faecalibacterium, Methylobacterium, and Megamonas. H. pylori eradication partially restored microbial diversity, as assessed during a median follow-up at 13 months after eradication therapy. However, post-eradication patients had less diversity than that in the controls and possessed a lower abundance of the five genera mentioned above. The eradication of H. pylori also altered the bacterial composition, but not to the same extent as that in controls. The microbial communities could be clustered into three separate groups: H. pylori-negative, pre-eradication, and post-eradication.

CONCLUSION

Changes in dysbiosis may persist long after the eradication of H. pylori in patients with a history of GC. Dysbiosis may be involved in the development of both primary and metachronous GC after the eradication of H. pylori in such patients.

Endoscopic grading of gastric atrophy on risk assessment of gastric neoplasia: A systematic review and meta-analysis

BACKGROUND AND AIM

Endoscopic examination of gastric atrophy has been developed to determine the extent of atrophy by identifying the atrophic border of gastric mucosa, but its value in predicting the risk of developing gastric neoplasms is not quantified. Thus, this systematic review and meta-analysis aim to assess the incidence risk of gastric neoplasms on the basis of endoscopic grading of gastric atrophy.

METHODS

Two authors independently searched the electronic databases (PubMed, Embase, and the Cochrane Library) from inception through December 31, 2019, without language restriction. The effect size on study outcomes is calculated using random-effects model and presented as risk ratio (RR) with 95% confidence interval (CI). Heterogeneity, publication bias, and quality of included studies were also assessed.

RESULTS

Fourteen retrospective studies are identified to perform systematic review and meta-analysis, 11 were cohort studies, and three were cross-sectional research. The pooled RR for developing gastric neoplasms is 3.89 (95% CI 2.92-5.17) among general patients with severe endoscopic atrophy. For patients who underwent endoscopic resection for early gastric neoplasms, nearly two times increased risk of synchronous or metachronous neoplasms is pooled (RR = 1.96, 95% CI 1.39-2.75). In terms of the type of endoscopic atrophy, patients with open-type endoscopic atrophy have a higher risk of gastric cancer development (RR 8.02; 95% CI 2.39-26.88) than those with close type. [Correction added on 22 December 2020, after first online publication: '(RR = 7.27; 95% CI 1.64-32.33)' has been corrected to '(RR 8.02; 95% CI 2.39-26.88)'] CONCLUSIONS: Grading endoscopic atrophy according to the Kimura-Takemoto classification can assess the risk of gastric neoplasia development. Patients with severe or open-type endoscopic gastric atrophy at baseline should undergo rigorous surveillance to early detect premalignant lesions and cancer.

Guidelines for endoscopic submucosal dissection and endoscopic mucosal resection for early gastric cancer (second edition)

In response to the rapid and wide acceptance and use of endoscopic treatments for early gastric cancer, the Japan Gastroenterological Endoscopy Society, in collaboration with the Japanese Gastric Cancer Association, produced "Guidelines for Endoscopic Submucosal Dissection and Endoscopic Mucosal Resection for Early Gastric Cancer" in 2014, as a set of basic guidelines in accordance with the principles of evidence-based medicine. At the time, a number of statements had to be established by consensus (the lowest evidence level), as evidence levels remained low for many specific areas in this field. However, in recent years, the number of well-designed clinical studies has been increasing. Based on new findings, we have issued the revised second edition of the above guidelines that cover the present state of knowledge. These guidelines are divided into the following seven categories: indications, preoperative diagnosis, techniques, evaluation of curability, complications, long-term postoperative surveillance, and histology.

Somatic alterations and mutational burden are potential predictive factors for metachronous development of early gastric cancer

The risk of developing metachronous gastric cancer (MGC) following curative endoscopic submucosal dissection (ESD) of early gastric cancer (EGC) remains even after eradicating Helicobacter pylori (HP) successfully. We screened initial EGC and adjacent non-cancerous mucosa ESD-resected specimens for somatic variants of 409 cancer-related genes, assessing their mutational burden (MB) to predict molecular markers for metachronous post-ESD development. We compared variants between ten patients diagnosed with MGC more than 3 years after ESD and ten age-matched patients who did not have MGC developments after successful HP eradication. We found no significant background differences between the two groups. In adjacent non-cancerous mucosa, the MB tended to be higher in the patients with metachronous developments than in the others. Somatic genomic alterations of RECQL4, JAK3, ARID1A, and MAGI1 genes were significantly associated with MGC development. The criteria including both the MB and their variants, which had potential significant values for predicting MGC. In conclusion, combined of assessing specific somatic variants and MB may be useful for predicting MGC development. This study included a limited number of subjects; however, our novel findings may encourage further exploration of the significance of the molecular features of EGC that predict MGC development, thereby promoting focused follow-up strategies and helping elucidate the mechanisms.

Gastric cancer screening in low incidence populations: Position statement of AEG, SEED and SEAP

This positioning document, sponsored by the Asociación Española de Gastroenterología, the Sociedad Española de Endoscopia Digestiva and the Sociedad Española de Anatomía Patológica, aims to establish recommendations for the screening of gastric cancer (GC) in low incidence populations, such as the Spanish. To establish the quality of the evidence and the levels of recommendation, we used the methodology based on the GRADE system (Grading of Recommendations Assessment, Development and Evaluation). We obtained a consensus among experts using a Delphi method. The document evaluates screening in the general population, individuals with relatives with GC and subjects with GC precursor lesions (GCPL). The goal of the interventions should be to reduce GC related mortality. We recommend the use of the OLGIM classification and determine the intestinal metaplasia (IM) subtype in the evaluation of GCPL. We do not recommend to establish endoscopic mass screening for GC or Helicobacter pylori. However, the document strongly recommends to treat H.pylori if the infection is detected, and the investigation and treatment in individuals with a family history of GC or with GCPL. Instead, we recommend against the use of serological tests to detect GCPL. Endoscopic screening is suggested only in individuals that meet familial GC criteria. As for individuals with GCPL, endoscopic surveillance is only suggested in extensive IM associated with additional risk factors (incomplete IM and/or a family history of GC), after resection of dysplastic lesions or in patients with dysplasia without visible lesion after a high quality gastroscopy with chromoendoscopy.

Prognostic factors for ESD of early gastric cancers: a systematic review and meta-analysis

Background and study aims  Gastric neoplasms are one of the leading types of cancer in the world and early detection is essential to improve prognosis. Endoscopy is the gold-standard diagnostic procedure and allows adequate treatment in selected cases. Endoscopic submucosal dissection (ESD) has been reported to safely address most early gastric cancers (EGCs), with high curability rates. However, data on prognostic factors related to ESDs of EGCs are conflicting. Therefore, we aimed to systematically review the available literature and to perform a meta-analysis to identify the relevant prognostic factors in this context. Methods  We performed this study according to PRISMA guidelines. Comparative studies assessing the relationship between curative resection or long-term curability rates and relevant prognostic factors were selected. Prognostic factors were demographic data, lesion features (location, morphology of the lesion, size, and depth of invasion), histological findings, Helycobacter pylori (HP) infection, presence of gastric a atrophy and body mass index (BMI). Finally, we also evaluated risk factors related to metachronous gastric neoplasm. Results  The initial search retrieved 2829 records among which 46 studies were included for systematic review and meta-analysis. The total sample comprised 28366 patients and 29282 lesions. Regarding curative resection, pooled data showed no significant influence of sex [odds ratio (OR): 1.15 (0,97, 1.36) P  = 0.10 I 2  = 47 %] , age [OR: 1.00 (0.61, 1.64) P  = 1.00 I 2  = 58 %], posterior vs non-posterior location [OR: 1.35 (0.81, 2.27) P  = 0.25 I 2  = 84 %], depressed vs von-depressed macroscopic type[OR: 1.21 (0.99, 1.49) P  = 0.07 I 2  = 0 %], non-upper vs upper location [OR: 1.41 (0.93, 2.14) P  = 0.10 I 2  = 77 %] and BMI [OR: 0.84 (0.57; 1.26) P  = 0.41 I 2  = 0 %]. Differentiated neoplasms presented greater chance of cure compare to undifferentiated [OR: 0.10 (0.07, 0.15) P  < 0.00001 I 2  = 0 %]. Ulcerated lesions had lower curative rates compared to non-ulcerated [OR: 3.92 (2.81, 5.47) P  < 0.00001 I 2  = 44 %]. Lesions smaller than 20 mm had greater chance of curative resection [OR: 3.94 (3.25, 4.78) P  < 0.00001 I 2  = 38 %]. Bleeding during procedure had lower curative rates compared to non-bleeding [OR: 2.13 (1.56, 2.93) P  < 0.0001 I 2  = 0 %]. Concerning long-term cure, female gender [OR 1.62 (1.33, 1.97) P  < 0.00001 I 2  = 0 %] and the mucosal over SM1 cancers were protective factors [OR: 0.08 (0.02, 0.39) P  = 0.002 I 2  = 86 %]. Gastric atrophy [OR: 0.60 (0.45, 0.81) P  = 0.0006 I 2  = 42 %] and the pepsinogen I/pepsinogen II ratio [OR 2.29 (1.47, 3.57) P  = 0.0002 I 2  = 0 %] were risk factors to metachronous gastric neoplasm. Conclusions  Ulcerated lesions, histology, bleeding and size > 20 mm are prognostic factors concerning curative resection. Regarding long-term cure, female gender and mucosal over SM1 cancer are predictive factors. Gastric atrophy and the pepsinogen ratio are risk factors for metachronous gastric neoplasm.

Recent advances in the detection and management of early gastric cancer and its precursors

Despite declines in incidence, gastric cancer remains a disease with a poor prognosis and limited treatment options due to its often late stage of diagnosis. In contrast, early gastric cancer has a good to excellent prognosis, with 5-year survival rates as high as 92.6% after endoscopic resection. There remains an East-West divide for this disease, with high incidence countries such as Japan seeing earlier diagnoses and reduced mortality, in part thanks to the success of a national screening programme. With missed cancers still prevalent at upper endoscopy in the West, and variable approaches to assessment of the high-risk stomach, the quality of endoscopy we provide must be a focus for improvement, with particular attention paid to the minority of patients at increased cancer risk. High-definition endoscopy with virtual chromoendoscopy is superior to white light endoscopy alone. These enhanced imaging modalities allow the experienced endoscopist to accurately and robustly detect high-risk lesions in the stomach. An endoscopy-led staging strategy would mean biopsies could be targeted to histologically confirm the endoscopic impression of premalignant lesions including atrophic gastritis, gastric intestinal metaplasia, dysplasia and early cancer. This approach to quality improvement will reduce missed diagnoses and, combined with the latest endoscopic resection techniques performed at expert centres, will improve early detection and ultimately patient outcomes. In this review, we outline the latest evidence relating to diagnosis, staging and treatment of early gastric cancer and its precursor lesions.

Chemoprevention of gastric cancer development after Helicobacter pylori eradication therapy in an East Asian population: Meta-analysis

BACKGROUND

Helicobacter pylori (H. pylori) infection is a risk factor for gastric cancer (GC), especially in East Asian populations. Most East Asian populations infected with H. pylori are at higher risk for GC than H. pylori-positive European and United States populations. H. pylori eradication therapy reduces gastric cancer risk in patients after endoscopic and operative resection for GC, as well as in non-GC patients with atrophic gastritis.

AIM

To clarify the chemopreventive effects of H. pylori eradication therapy in an East Asian population with a high incidence of GC.

METHODS

PubMed and the Cochrane library were searched for randomized control trials (RCTs) and cohort studies published in English up to March 2019. Subgroup analyses were conducted with regard to study designs (i.e., RCTs or cohort studies), country where the study was conducted (i.e., Japan, China, and South Korea), and observation periods (i.e., ≤ 5 years and > 5 years). The heterogeneity and publication bias were also measured.

RESULTS

For non-GC patients with atrophic gastritis and patients after resection for GC, 4 and 4 RCTs and 12 and 18 cohort studies were included, respectively. In RCTs, the median incidence of GC for the untreated control groups and the treatment groups was 272.7 (180.4-322.4) and 162.3 (72.5-588.2) per 100000 person-years in non-GC cases with atrophic gastritis and 1790.7 (406.5-2941.2) and 1126.2 (678.7-1223.1) per 100000 person-years in cases of after resection for GC. Compared with non-treated H. pylori-positive controls, the eradication groups had a significantly reduced risk of GC, with a relative risk of 0.67 [95% confidence interval (CI): 0.47-0.96] for non-GC patients with atrophic gastritis and 0.51 (0.36-0.73) for patients after resection for GC in the RCTs, and 0.39 (0.30-0.51) for patients with gastritis and 0.54 (0.44-0.67) for patients after resection in cohort studies.

CONCLUSION

In the East Asian population with a high risk of GC, H. pylori eradication effectively reduced the risk of GC, irrespective of past history of previous cancer.

Helicobacter pylori Infection following Endoscopic Resection of Early Gastric Cancer

The role of Helicobacter pylori (H. pylori) infection in patients following endoscopic resection of early gastric cancer (EGC) remains unclear. This article presents a review of literature published in the past 15 years. H. pylori-mediated persistent methylation levels are associated with the development of metachronous gastric cancer. The methylation of certain specific genes can be used to identify patients with a high risk of metachronous gastric cancer even after H. pylori eradication. H. pylori eradication after endoscopic resection should be performed as early as possible for eradication success and prevention of metachronous precancerous lesions. Although whether the eradication of H. pylori could prevent the development of metachronous cancer after endoscopic resection is controversial, several meta-analyses concluded that H. pylori eradication could reduce the incidence of metachronous gastric cancer significantly. In addition, H. pylori eradication in gastric cancer survivors after endoscopic resection could reduce healthcare cost and save lives in a cost-effective way. Taken together, H. pylori eradication after endoscopic resection of EGC is recommended as prevention for metachronous precancerous lesions and metachronous gastric cancer.

The eradication of Helicobacter pylori restores rather than disturbs the gastrointestinal microbiota in asymptomatic young adults

BACKGROUND

The eradication of Helicobacter pylori (H pylori) has been suggested to reduce the risk of gastric cancer, but its impact on the gut microbiota has attracted public attention. This study aimed to investigate the short-term and long-term effects of bismuth quadruple therapy on both gastric and fecal microbiota.

METHODS

Ten asymptomatic young adults with H pylori-related gastritis were treated with bismuth quadruple therapy for 14 days, and 7 age-matched adults without H pylori infection were enrolled as healthy controls. Both fecal and gastric mucosa samples were collected from H pylori-positive patients at weeks 0, 6, and 26, while fecal samples were collected from healthy controls. The gastric and gut microbiota were analyzed by 16S rRNA gene sequencing.

RESULTS

The structure of the gastric microbiota was significantly changed after the eradication of H pylori with increased alpha diversity over time. The relative abundance of H pylori sharply decreased from more than 70% to nearly 0% after treatment, while some beneficial bacteria, such as Lactobacillus and Bifidobacterium, were increased. The microbial diversity of gut microbiota was higher in H pylori-infected patients than in healthy controls, which tended to decrease after eradication. The potentially beneficial gut bacteria Blautia and Lachnoclostridium were enriched at week 26 compared to week 0, while the pathogenic Alistipes were depleted to a level close to that of the healthy controls.

CONCLUSIONS

Bismuth quadruple therapy for H pylori eradication can restore the diversity of gastric microbiota with enrichment of beneficial bacteria. The composition of gut microbiota after H pylori eradication trends toward healthy status instead of becoming dysbiotic.

Combined Gastric and Colorectal Cancer Screening-A New Strategy

BACKGROUND

Our aim was to evaluate the feasibility of a serological assessment of gastric cancer risk in patients undergoing colonoscopy in countries with low-to-moderate incidence rates.

METHODS

Serum samples were prospectively collected from 453 patients (>50 years old) undergoing colonoscopies. Of these, 279 (61.6%) also underwent gastroscopy to correlate the results for serum pepsinogen I and II (sPG-I and sPG-II), sPG-I/II ratio, and anti-H. pylori antibodies with gastric histopathology findings (graded according to the updated Sydney classification and the Operative Link of Gastritis Assessment (OLGA) and the Operative Link for Gastric Intestinal Metaplasia assessment (OLGIM) systems).

RESULTS

H. pylori was found in 85 patients (30.5%). Chronic atrophic gastritis was diagnosed in 89 (31.9%) patients. High-risk OLGA (III⁻IV) stages were present in 24 patients, and high-risk OLGIM stages were present in 14 patients. There was an inverse correlation of sPG-I with the degree of atrophy and intestinal metaplasia (IM), as well as with the respective OLGA (r = -0.425; p < 0.001) and OLGIM (r = -0.303; p < 0.001) stages. A pathological sPG-I result was associated with a relative risk (RR) of 12.2 (95% confidence interval: 6.29⁻23.54; p < 0.001) for gastric preneoplastic changes.

CONCLUSIONS

The assessment of serum pepsinogen allows the identification of patients at increased risk of gastric cancer. A prevention strategy of combining a screening colonoscopy with a serological screening for preneoplastic gastric changes should be considered in the general population.