Changing trends in the prevalence of H. pylori infection in Japan (1908-2003): a systematic review and meta-regression analysis of 170,752 individuals

Time trend analysis of rare cancer incidence 2011-2018: Nationwide population-based cancer registries in Japan

Rare cancers collectively account for a significant proportion of the overall cancer burden in Japan. We aimed to describe and examine the incidence of each rare cancer and the temporal changes using the internationally agreed rare cancer classification. Cancer cases registered in regional population-based cancer registries from 2011 to 2015 and the National Cancer Registry (NCR) from 2016 to 2018 were classified into 18 families, 68 Tier-1 cancer groupings, and 216 single cancer entities based on the RARECAREnet list. Crude incidence rates and age-standardized incidence rates (ASR) were calculated for Tier-1 and Tier-2 cancers. The annual percent change and the 95% and 99% confidence limits for annual ASR for each of the 68 Tier-1 cancers were estimated using the log-linear regression of the weighted least squares method. The differences in ASRs between 2011 and 2018 were evaluated as an absolute change. A total of 5,640,879 cases were classified into Tier-1 and Tier-2 cancers. The ASRs of 18 out of 52 Tier-1 cancers in the rare cancer families increased, whereas the ASR for epithelial tumors of gallbladder decreased. The ASRs of 6 out of the 16 Tier-1 cancers in the common cancer families increased, whereas those of epithelial tumors of stomach and liver decreased. There was no significant change in the incidence of the other 40 Tier-1 cancers. The incidence of several cancers increased due to the dissemination of diagnostic concepts, improved diagnostic techniques, changes in coding practice, and the initiation of the NCR.

Comparison of platelet transfusion effectiveness between Helicobacter pylori-positive and -negative immune thrombocytopenia

Immune thrombocytopenia (ITP) is characterized by early platelet destruction and impaired platelet production. Helicobacter pylori (H. pylori) infection seems to contribute to the pathogenesis in certain ITP patients in Japan. We compared the effectiveness of platelet transfusion in severe ITP in the presence or absence of H. pylori. The median corrected count increment (CCI) at 24 h after platelet transfusion (CCI-24) of the H. pylori-positive ITP patients was higher than that of the H. pylori-negative ITP patients (6463 vs. 754, p < 0.001), and the CCI-1 was also in the same direction but not significant (23 351 vs. 11 578). Multiple regression analyses showed that H. pylori infection was independently associated with CCI-24. Our study suggests that platelet transfusion may be more effective in H. pylori-positive ITP patients.

Characterization of the unique oral microbiome of children harboring Helicobacter pylori in the oral cavity

Objective

Helicobacter pylori infection is acquired in childhood via the oral cavity, although its relationship with the characteristics of the oral microbiome has not been elucidated. In this study, we performed comprehensive analysis of the oral microbiome in children and adults with or without H. pylori in the oral cavity.

Methods

Bacterial DNA was extracted from 41 adult and 21 child saliva specimens, and H. pylori was detected using PCR. 16S rRNA gene amplification was performed for next-generation sequencing. Bioinformatic analyses were conducted using Quantitative Insights into Microbial Ecology 2 (QIIME 2).

Results

Faith's phylogenetic diversity analysis showed a significant difference between H. pylori-negative adult and child specimens in terms of α-diversity (p < 0.05), while no significant difference was observed between H. pylori-positive adult and child specimens. There was also a significant difference in β-diversity between H. pylori-positive and negative child specimens (p < 0.05). Taxonomic analysis at the genus level revealed that Porphyromonas was the only bacterium that was significantly more abundant in both H. pylori-positive adults and children than in corresponding negative specimens (p < 0.01 and p < 0.05, respectively).

Conclusion

These results suggest unique oral microbiome characteristics in children with H. pylori infection in the oral cavity.

Chronological Trend of Opportunistic Endoscopic Screening for Gastric Cancer and Atrophic Gastritis

BACKGROUND

Opportunistic endoscopic screening for gastric cancer was initiated in 2004 at our institute. We investigated chronological trends in gastric cancer detection rates based on individual characteristics and atrophic gastritis prevalence.

METHODS

Overall, 15,081 asymptomatic individuals aged ≥40 years without a medical history of gastric cancer underwent first-time esophagogastroduodenoscopy in our institute between February 2004 and December 2017. We retrospectively investigated individual characteristics and endoscopic diagnoses by period (early period: 2004-2007, middle period: 2008-2012, and late period: 2013-2017), clarified the long-term detection rate and the characteristics of endoscopic screening-detected gastric cancer, and evaluated the relationship between gastric cancer and atrophic gastritis.

RESULTS

Gastric cancer detection rates in the early, middle, and late periods were 1.01% (76/7,503, men/women: 4,360/3,143, average age: 59.4 years, prevalence of atrophic gastritis: 72%), 0.69% (40/5,820, men/women: 3,668/2,152, average age: 56.8 years, prevalence of atrophic gastritis: 48%), and 0.46% (8/1,758, men/women: 1,083/675, average age: 58.7 years, prevalence of atrophic gastritis: 37%), respectively. Multivariate analysis revealed that male sex (odds ratio 1.92, 95% confidence interval 1.28-2.95), age ≥75 years (2.73, 95% CI 1.32-5.05), and atrophic gastritis (C1-C3: 2.21, 1.36-3.73, O1-O3: 5.36, 3.17-9.30) were significantly associated with the incidence of gastric cancer.

CONCLUSIONS

The gastric cancer detection rate and atrophic gastritis prevalence have decreased over time. However, continuing endoscopic screening is important, especially for those at a high risk of developing gastric cancer complicated by severe atrophic gastritis.

A novel predictive formula for highly accurate discrimination between truly Helicobacter pylori-uninfected and currently infected/spontaneously eradicated individuals for gastric cancer screening

The ABC classification, which categorizes gastric cancer risk based on serum Helicobacter pylori (H pylori) antibody and pepsinogen levels, has a limitation of potentially misclassifying high-risk individuals as low risk. To overcome the problem, we previously developed a 4-parameter predictive formula (age, serum H pylori antibody, PGI, and PGII) using logistic regression analysis to accurately identify low-risk truly H pylori-uninfected status. Our predictive formula demonstrated superior sensitivity and specificity in distinguishing between low-risk truly uninfected individuals and high-risk currently/spontaneously eradicated status individuals, compared to the modified ABC classification based on latex immunoassay kits (traditional 3-parameter model). This study aimed to revalidate the diagnostic accuracy of the predictive formula in a new and different study population. We applied the predictive formula to the target population and compared the sensitivity and specificity with those of the traditional 3-parameter model. A total of 788 enrollees were analyzed: 703 were classified as truly uninfected, 45 as currently infected, and 40 as spontaneously eradicated according to the results of stool antigen testing and endoscopic findings. The sensitivities and specificities of the predictive formula and the traditional 3-parameter model were 89.5% and 87.1% versus 89.8% and 80.0%, respectively. The specificity of the predictive formula was superior in the 70 to 89 age range and H pylori antibody < 3 U/mL groups. The predictive formula had higher specificity than the traditional 3-parameter model. The results should contribute to efficient gastric cancer screening by predicting H pylori infection status.

Population-based X-ray gastric cancer screening in Hiroshima prefecture, Japan

BACKGROUND

X-ray gastric cancer (GC) screening has been shown to decrease mortality. Population-based X-ray GC screening has been performed in Hiroshima Prefecture, Japan, since 1983 but time trends and the efficacy of the method over 39 years have not been assessed.

AIM

To evaluate time trends and efficacy of population-based X-ray GC screening and identify challenges and suggested solutions for the future.

METHODS

This was a population-based retrospective study. The data were derived from aggregated data of the Hiroshima Regional Health Medical Promotion Organization, including the number and rate of participants and those requiring esophagogastroduodenoscopies (EGDs), the number and rate of participants diagnosed as having GC, and the positive predictive value of the abnormal findings detected by X-ray and confirmed by EGDs. The number and rate of esophageal cancers were also collected. Further, the cost of detecting one GC was evaluated.

RESULTS

The number of participants has decreased during the last four decades, from 39925 in 1983 to 12923 in 2021. The rate of those requiring EGDs decreased significantly in recent years (P < 0.001). The number of participants diagnosed as having GC has also declined, from 76 to 10 cases. However, the rate of cases diagnosed as GC among the participants remained around 0.1%. The positive predictive value increased significantly in recent years except during 1983-1991. The number and rate of accidentally detected esophageal cancers have risen recently, from 0% in 2008 to 0.02% in 2021, one-fifth of the diagnosis rate of GC. One GC diagnosis costs approximately 4200000 Japanese Yen (30000 United States Dollars) for the X-ray screenings and EGDs.

CONCLUSION

X-ray GC screening in Hiroshima has been efficient, but one challenge is the cost. Esophageal cancers may also need to be considered because they have gradually increased in recent years.

Impact of treatment guidelines and pivotal clinical trial results on a surgeon's decision regarding treatment for gastric cancer: a retrospective cohort study using the National Clinical Database

PURPOSES

The present study evaluated the impact of clinical guidelines for gastric cancer surgery on surgeons' choice of procedure in real-world practice. We focused on the 2014 guideline revision recommending laparoscopic surgery and the evidence concerning splenectomy for prophylactic lymphadenectomy reported in 2015 using the National Clinical Database, which is the most comprehensive database in Japan.

METHODS

We investigated the monthly percentages of laparoscopic distal gastrectomies performed for stage I gastric cancer (LDG%) and splenectomies performed during total gastrectomy for advanced cancer (TGS%) between 2014 and 2017. We evaluated the descriptive statistics of the time-series changes in the LDG%, TGS%, and annual trends of outcomes.

RESULTS

In total, 124,787 patients were enrolled. The mean LDG% and TGS% were 69.8% and 9.2%, respectively. The LDG% and TGS% were 66.4% and 16.7%, respectively, in January 2014 and 73.1% and 5.9%, respectively, in December 2017. LDG% consistently increased, and TGS% showed a consistent downward trend throughout the observation period. There was no significant change in this trend after the publication of the guideline recommendations or clinical trial results.

CONCLUSION

No significant changes in surgical procedures were observed after publication of the guidelines or results of clinical trials.

Randomized controlled trial comparing the costs of gastric cancer screening systems between serological risk-based upper gastrointestinal endoscopy and the existing barium photofluorography: gastric cancer screening labeled by serum examination in place of aged gastric cancer organized screening systems (GALAPAGOS study)

BACKGROUND

Although the risk of gastric cancer can be stratified according to Helicobacter pylori (H. pylori) IgG antibody titer and pepsinogen levels (ABC classification), a population-based gastric cancer screening system combining serological tests and endoscopy has not been introduced. This study aimed to compare the total testing cost per participant between the ABC classification method and the existing protocol.

METHODS

Using the minimization method with sex and age as allocation factors, 1206 participants were randomly assigned to the following two methods for a 5-year intervention: barium photofluorography as primary examination followed by detailed examination with upper gastrointestinal endoscopy (Ba-Endo) and risk-based upper gastrointestinal endoscopy by ABC classification (ABC-Endo). The primary endpoint was the total testing cost per participant over a 5-year period. The secondary endpoint was the expense required to detect one gastric cancer.

RESULTS

The total testing cost per participant was 39,711 yen in Ba-Endo (604 participants) and 45,227 yen in ABC-Endo (602 participants), with the latter being significantly higher (p < 0.001). During the intervention period, gastric cancer was found in 11 and eight participants in Ba-Endo and ABC-Endo, respectively. The expenses required to detect one gastric cancer were 2,240,931 yen in Ba-Endo and 3,486,662 yen in ABC-Endo.

CONCLUSIONS

The testing cost per participant turned out to be higher in the ABC-Endo group than in the Ba-Endo group. This superiority trial, based on the hypothesis that the cost of testing is lower for ABC-Endo than for Ba-Endo, was rejected.

Helicobacter pylori Infections in Children

In the context of epidemiology, host response, disease presentation, diagnosis, and treatment management, the manifestation of Helicobacter pylori (H. pylori) infection diverges between children and adults. H. pylori infection stands out as one of the most prevalent bacterial infections globally, and its prevalence in both children and adults is decreasing in many developing countries but some still struggle with a high prevalence of pediatric H. pylori infection and its consequences. The majority of infected children are asymptomatic and pediatric studies do not support the involvement of H. pylori in functional disorders such as recurrent abdominal pain. The pathophysiology of H. pylori infection relies on complex bacterial virulence mechanisms and their interaction with the host immune system and environmental factors. This interaction gives rise to diverse gastritis phenotypes, which subsequently influence the potential development of various gastroduodenal pathologies. In clinical settings, the diagnosis of this infection in childhood requires an upper gastrointestinal endoscopic exam with mucosal biopsy samples for histology and culture, or Polymerase Chain Reaction (PCR) at the very least. When warranted, eradication treatment should be given when good compliance is expected, and there should be systematic use of a treatment adapted to the antimicrobial susceptibility profile. To combat the burgeoning threat of multidrug resistance, vigilant surveillance of resistance patterns and strategic antibiotic management are paramount.

Impact of local human microbiota on the allergic diseases: Organ-organ interaction

The homogeneous impact of local dysbiosis on the development of allergic diseases in the same organ has been thoroughly studied. However, much less is known about the heterogeneous influence of dysbiosis within one organ on allergic diseases in other organs. A comprehensive analysis of the current scientific literature revealed that most of the relevant publications focus on only three organs: gut, airways, and skin. Moreover, the interactions appear to be mainly unidirectional, that is, dysbiotic conditions of the gut being associated with allergic diseases of the airways and the skin. Similar to homogeneous interactions, early life appears to be not only a crucial period for the formation of the microbiota in one organ but also for the later development of allergic diseases in other organs. In particular, we were able to identify a number of specific bacterial and fungal species/genera in the intestine that were repeatedly associated in the literature with either increased or decreased allergic diseases of the skin, like atopic dermatitis, or the airways, like allergic rhinitis and asthma. The reported studies indicate that in addition to the composition of the microbiome, also the relative abundance of certain microbial species and the overall diversity are associated with allergic diseases of the corresponding organs. As anticipated for human association studies, the underlying mechanisms of the organ-organ crosstalk could not be clearly resolved yet. Thus, further work, in particular experimental animal studies are required to elucidate the mechanisms linking dysbiotic conditions of one organ to allergic diseases in other organs.

Comparison of Gastric Cancer Risk Classifications Using Conventional and New Pepsinogen Criteria

Background

New serum pepsinogen (PG) criteria have been shown to indicate more accurately infection with Helicobacter pylori (H. pylori). We sought to improve risk classification for gastric cancer by adopting the new PG criteria with the addition of an H. pylori antibody test.

Methods

The study participants were 275 patients with gastric cancer and 275 apparently healthy controls from case-control study data. We cross-sectionally compared the results of gastric cancer risk classifications that were based on a combination of the new PG criteria (PG II ≥ 10 ng/mL or PG I/II ≤ 5) and an H. pylori antibody test with those that were based on a combination of the conventional criteria (PG I ≤ 70 ng/mL and PG I/PG II ≤ 3) and an H. pylori antibody test.

Results

Applying the conventional criteria resulted in 89 controls being classified as low risk. Applying the new criteria resulted in 23 controls (bootstrapped 95% confidence intervals [CI]: 14, 32) being additionally classified as high risk. Eight patients with gastric cancer were classified as low risk using the conventional criteria; however, six of these patients were classified as high risk by the new criteria (bootstrapped 95% CI: 2, 11).

Conclusions

Compared with the conventional criteria, the new PG criteria with H. pylori antibody reduced instances of gastric cancer cases being misclassified as low risk. These findings suggest that the new PG criteria may help identify individuals at high risk of developing gastric cancer.

Development of a modified ABC method among Helicobacter pylori infected but serum pepsinogen test-negative individuals

BACKGROUND

Although the ABC method for gastric cancer (GC) screening has been widely adopted in Japan, it may not be suitable for other countries due to population heterogeneity and different tumor histology. We aim to develop a modified ABC method to improve GC screening performance, especially among Helicobacter pylori (Hp) infected but serum pepsinogen (sPG) test-negative individuals.

METHODS

A total of 4745 participants were recruited from Tianjin, China, and were classified into four groups by combined assay for Hp infection and sPG concentrations: Group A (Hp [-], PG [-]), Group B (Hp [+], PG [-]), Group C (Hp [+], PG [+]), and Group D (Hp [-], PG [+]). We used receiver-operating characteristic (ROC) curves analysis and minimum p value method to determine the optimal cutoff point for PG II in Group B. We performed logistic regressions to examine the risk of GC across different subgroups. In addition to the derivation set, the performance of the modified ABC method was also evaluated in an external set involving 16,292 participants from Liaoning, China.

RESULTS

In the modified ABC method, we further classified Group B as low-risk (Group B1) and high-risk subgroups (Group B2) using optimal sPG II cutoff point (20.0 ng/mL) by ROC curves analysis and minimum p value method. Compared with Group B1, Group B2 had a significantly higher risk of GC (adjusted OR = 2.54, 95% CI = 1.94-3.33). The modified ABC method showed good discrimination for GC (AUC = 0.61, 95% CI = 0.59-0.63) and improved risk reclassification (NRI = 0.11, p < .01). Similar results were observed in the validation dataset.

CONCLUSIONS

The modified ABC method can effectively identify high-risk population for GC among Hp-infected but sPG test-negative participants in China.

Analysis of Genetic Relatedness between Gastric and Oral Helicobacter pylori in Patients with Early Gastric Cancer Using Multilocus Sequence Typing

The oral cavity is the second most colonized site of Helicobacter pylori after the stomach. This study aimed to compare the genetic relatedness between gastric and oral H. pylori in Japanese patients with early gastric cancer through multilocus sequence typing (MLST) analysis using eight housekeeping genes. Gastric biopsy specimens and oral samples were collected from 21 patients with a fecal antigen test positive for H. pylori. The number of H. pylori allelic profiles ranged from zero to eight since the yield of DNA was small even when the nested PCR was performed. MLST analysis revealed that only one patient had a matching oral and gastric H. pylori genotype, suggesting that different genotypes of H. pylori inhabit the oral cavity and gastric mucosa. The phylogenetic analysis showed that oral H. pylori in six patients was similar to gastric H. pylori, implying that the two strains are related but not of the same origin, and those strains may be infected on separate occasions. It is necessary to establish a culture method for oral H. pylori to elucidate whether the oral cavity acts as the source of gastric infection, as our analysis was based on a limited number of allele sequences.

Transcriptome analysis reveals the essential role of NK2 homeobox 1/thyroid transcription factor 1 (NKX2-1/TTF-1) in gastric adenocarcinoma of fundic-gland type

BACKGROUND

Gastric adenocarcinoma of fundic-gland type (GA-FG) is a gastric malignancy with little relation to Helicobacter pylori. Clinical characteristics of GA-FG have been established, but molecular mechanisms leading to tumorigenesis have not yet been elucidated.

METHODS

We subjected three GA-FG tumors-normal mucosa pairs to microarray analysis. Network analysis was performed for the top 30 up-regulated gene transcripts, followed by immunohistochemical staining to confirm the gene expression analysis results. AGS and NUGC4 cells were transfected with the gene-encoding NK2 homeobox 1/thyroid transcription factor 1 (NKX2-1/TTF-1) to evaluate transcriptional changes in its target genes.

RESULTS

Comprehensive gene expression analysis identified 1410 up-regulated and 1395 down-regulated gene probes with ≥ two-fold difference in expression. Among the top 30 up-regulated genes in GA-FG, we identified transcription factor NKX2-1/TTF-1, a master regulator of lung/thyroid differentiation, together with surfactant protein B (SFTPB), SFTPC, and secretoglobin family 3A member 2(SCGB3A2), which are regulated by NKX2-1/TTF-1. Immunohistochemical analysis of 16 GA-FG specimens demonstrated significantly higher NKX2-1/TTF-1 and SFTPB levels, as compared to that in adjacent normal mucosa (P < 0.05), while SCGB3A2 levels did not differ (P = 0.341). Transduction of NKX2-1/TTF-1 into AGS and NUGC4 cells induced transactivation of SFTPB and SFTPC, indicating that NKX2-1/TTF-1 can function as normally in gastric cells as it can in the lung cells.

CONCLUSIONS

Our first transcriptome analysis of GA-FG indicates significant expression of NKX2-1/TTF1 in GA-FG. Immunohistochemistry and cell biology show ectopic expression and normal transactivation ability of NKX2-1/TTF-1, suggesting that it plays an essential role in GA-FG development.

A Population-Based Helicobacter pylori Eradication Strategy Is More Cost-Effective than Endoscopic Screening

BACKGROUND

Helicobacter pylori (HP) eradication therapy is an efficient primary prevention method to reduce gastric cancer development. In Japan, biennial endoscopic screening for individuals aged 50 years and older is currently conducted as a national gastric cancer prevention program.

AIMS

We aimed to evaluate which strategy was the most optimal and cost-effective among HP eradication strategy, annual, biennial, and triennial endoscopic screening, and no screening as a national gastric cancer prevention program.

METHODS

We developed a state-transition model for HP eradication strategy, annual, biennial, and triennial endoscopic screening, and no screening using a healthcare payer perspective and a lifetime horizon. We targeted a hypothetical cohort of the Japanese population in their 20 s to 80 s. The main outcomes were costs, quality-adjusted life-years (QALYs), incremental cost-effectiveness ratios, gastric cancer cases, and deaths from gastric cancer. We performed one-way, two-way, and probabilistic sensitivity analyses.

RESULTS

HP eradication strategy was more cost-effective than endoscopic screening at any interval in all age groups. Cost-effectiveness was sensitive to HP infection rate. Cost-effective acceptability curves by Monte Carlo simulations for 10,000 trials demonstrated that HP eradication strategy was 100% cost-effective at a willingness-to-pay threshold of US$50,000 per QALY gained in all age groups. Over a lifetime, HP eradication strategy saves US$28.07 billion, increases 37.16 million QALYs, prevents 4.47 million gastric cancer cases, and saves 319,870 lives from gastric cancer.

CONCLUSION

A population-based HP eradication strategy is optimal and cost-effective for a national gastric cancer prevention program in Japan, replacing the current secondary prevention-focused biennial endoscopic screening.

Long-Term Projections of Cancer Incidence and Mortality in Japan and Decomposition Analysis of Changes in Cancer Burden, 2020-2054: An Empirical Validation Approach

PURPOSE

The aim of this study was to project new cancer cases/deaths forward to 2054, and decompose changes in cancer cases/deaths to assess the impact of demographic transitions on cancer burden.

METHODS

We collected data on cancer cases/deaths up to 2019, empirically validated the projection performance of multiple statistical models, and selected optimal models by applying time series cross-validation.

RESULTS

We showed an increasing number of new cancer cases but decreasing number of cancer deaths in both genders, with a large burden attributed to population aging. We observed the increasing incidence rates in most cancer sites but reducing rates in some infection-associated cancers, including stomach and liver cancers. Colorectal and lung cancers were projected to remain as leading cancer burdens of both incidence and mortality in Japan over 2020-2054, while prostate and female breast cancers would be the leading incidence burdens among men and women, respectively.

CONCLUSIONS

Findings from decomposition analysis require more supportive interventions for reducing mortality and improving the quality of life of Japanese elders. We emphasize the important role of governments and policymakers in reforming policies for controlling cancer risk factors, including oncogenic infections. The rapid increase and continued presence of those cancer burdens associated with modifiable risk factors warrant greater efforts in cancer control programs, specifically in enhancing cancer screening and controlling cancer risk factors in Japan.

Enhancement of DNA hypomethylation alterations by gastric and bile acids promotes chromosomal instability in Barrett's epithelial cell line

Gastric and bile acid reflux leads to chronic inflammation, resulting in methylation alterations in Barrett's esophagus (BE) together with chromosomal instability (CIN). We investigated DNA hypomethylation following acid exposure and confirmed its significance in BE-related carcinogenesis by inducing CIN in vitro. OACP4C, an esophageal cancer cell line, and CP-A, a non-dysplastic cell line originating from BE, were exposed to acidic conditions using deoxycholic acid. CP-A exhibited substantially increased DNA hypomethylation of alpha satellite sequences in the centromere region, as well as increased levels of alpha satellite transcripts, but no changes were observed in the long interspersed nucleotide element-1 sequences distributed throughout the entire genome. These changes were not clearly found in OACP4C. Copy number changes at specific chromosomes were identified in CP-A, along with an increased number of cells exhibiting abnormal segregations, whereas these changes were rarely observed in OACP4C. The changes were maintained after several cell divisions. These findings suggest that alpha satellites are likely targets of DNA hypomethylation induced by acid exposure. CP-A was more sensitive to acid exposure than OACP4C, indicating that acid-induced DNA hypomethylation is involved in cancer development rather than progression, which could be involved in the underlying mechanism of esophagogastric junction carcinoma development.

Increasing trend of Helicobacter pylori-uninfected gastric cancer without gastric atrophy

The prevalence of Helicobacter pylori (H. pylori) has decreased during several decades due to improvements in the sanitary environment in Japan. Consequently, a relative increase in the incidence of H. pylori-uninfected gastric cancer is expected. We analyzed the trends in H. pylori-uninfected gastric cancer. Two hundred fifty-eight patients with gastric cancer were retrospectively analyzed. The study was divided into four periods: 2008-2011 (first period), 2012-2014 (second period), 2015-2017 (third period), and 2018-2021 (fourth period). The status of H. pylori infection was divided into four categories: uninfected, successful eradication, spontaneous eradication, and persistent infection. Gastric mucosal atrophy was divided into six grades according to the Kimura-Takemoto classification. The proportion of H. pylori infections significantly changed over the study period (p = 0.007). In particular, the rate of H. pylori-uninfected gastric cancer tended to increase over time (0%, 2.9%, 4.9%, and 13.4% in the first, second, third, and fourth periods, respectively; p = 0.0013). The rate of no atrophy (C-0) in gastric cancer tended to increase over time (0%, 2.9%, 4.9%, and 11.0% in the first, second, third, and fourth periods, respectively; p = 0.0046). In conclusion, the rate of H. pylori-uninfected gastric cancer without gastric atrophy tended to increase over time.

Declining trends of prevalence of Helicobacter pylori infection and incidence of gastric cancer in Taiwan: An updated cross-sectional survey and meta-analysis

BACKGROUND

We aimed to assess the latest prevalence and secular trend of Helicobacter pylori infection and its association with the incidence and mortality of gastric cancer in Taiwan.

MATERIALS AND METHODS

Adults naive to H. pylori eradication received ¹³ C-urea breath test (¹³ C-UBT), H. pylori stool antigen test, and serology test during 2019-2020 in this prospective screening program. Children and adolescent aged between 7 and 19 years received ¹³ C-UBT for H. pylori screening. We also conducted a systematic review and meta-analysis to assess the secular trend of prevalence of H. pylori from 1990 to 2020 in Taiwan. The secular trends of age-standardized incidence and mortality of gastric cancer were obtained from the Taiwan Cancer Registry.

RESULTS

A total of 1494 participants were enrolled, including 294 children or adolescents and 1200 adults. The overall prevalence of active H. pylori infection by ¹³ C-UBT was 26.6% (397/1494), which was 30.8% in adults and 9.5% in adolescents/children. The age-standardized prevalence of active H. pylori infection was 32.3% in adults after adjustment of the population structure in Taiwan. Of the 29 studies including 38,597 subjects eligible for the meta-analysis, the pooled prevalence of H. pylori infection decreased from 63.8% (95% CI: 55.9%-71%) in 1990-2000 to 28.2% (95% CI:21.8%-35.6%) in 2016-2020. The age-standardized incidence and mortality of gastric cancer have also declined from 15.2 to 10.75 per 100,000, respectively, in 1999 to 9.29 and 5.4 per 100,000, respectively, in 2019.

CONCLUSIONS

The prevalence of H. pylori infection has declined in Taiwan, which correlates with the declining trends of age-standardized incidence and mortality of gastric cancer in Taiwan.

Reevaluation of Gastric Cancer Screening by Levin's Equation

INTRODUCTION

This study aimed to reevaluate the effectiveness of fluoroscopy and endoscopy in reducing gastric cancer mortality at the population level.

METHODS

Crude and age-adjusted mortality rates of gastric cancer and the introduction rates of gastric cancer screening were extracted from the Cancer Registry and Statistics database. The population-attributable risk (PAR) percent of no screening for gastric cancer mortality was calculated using Levin's equation. The PAR of each mortality rate in the no-screening group was estimated as follows: mortality × PAR%. The Jonckheere-Terpstra test for trends and linear regression were performed to compare the PAR of gastric cancer mortality rates among the decades.

RESULTS

The PAR of crude and age-adjusted mortality rates in the no-screening group significantly decreased in the total population ( P for trend <0.001), as well as individually in the male ( P for trend <0.001) and female ( P for trend <0.001) populations. The PAR of the crude mortality rate in the female population significantly decreased in 2000-2009 and 2010-2019, compared with that in 1980-1989. There was no significant difference in the PAR of crude mortality rate in the male population among the decades. The PAR of the age-adjusted mortality rate significantly decreased in 2000-2009 and 2010-2019, compared with that in 1980-1989, in the male and female populations.

DISCUSSION

PAR% and PAR of no screening for gastric cancer mortality could be estimated using Levin's equation, and the effectiveness of the present gastric cancer screenings with fluoroscopy and endoscopy has been decreasing, especially in the female population.

Changes in prevalence of Helicobacter pylori in Japan from 2008 to 2018: a repeated cross-sectional study

OBJECTIVES

To understand the recent prevalence and time trends of Helicobacter pylori infection rates in the Japanese population.

DESIGN

Repeated cross-sectional study.

PARTICIPANTS

A total of 22 120 workers (age: 35-65 years) from one Japanese company, who underwent serum H. pylori antibody tests in a health check-up between 2008 and 2018.

MEASURES

H. pylori infection rates among participants aged 35 years from 2008 to 2018, and participants aged 35, 40, 45, and 50-65 years in 2018, based on the results of serum antibody tests, were analysed. In the 2018 analysis, in addition to the antibody test results, all participants who had undergone eradication treatment for H. pylori were considered as infected. Trends were examined using joinpoint analysis.

RESULTS

H. pylori was detected in 1100 of 7586 male and 190 of 1739 female participants aged 35 years. Annual infection rates among those aged 35 years showed linear downward trends as follows: men, 17.5% in 2008 to 10.1% in 2018 (slope: -0.66); women, 12.3% in 2008 to 9.2% in 2018 (slope: -0.51) without joinpoints. In the 2018 analysis, 2432 of 9580 men and 431 of 1854 women were H. pylori positive. Infection rates tended to increase with older age (men: 11.0% (35 years) to 47.7% (65 years); women: 10.0% (35 years) to 40.0% (65 years)), and showed joinpoints in both sexes (men: 54 years; women: 45 years). Although both the first and second trends were upward, the second trend for both men and women was steeper than the first trend (p<0.05).

CONCLUSIONS

Our study demonstrated that in the previous 11 years, infection rates of H. pylori in 35-year-old male and female Japanese workers have constantly decreased, and furthermore, analysis of various age groups showed joinpoints around 50 years, suggesting a consistent declining trend in H. pylori infection rates in Japan.

Prevalence of Helicobacter pylori infection in the general population evaluated by a resident-register-based epidemiological study

BACKGROUND

The current status of Helicobacter pylori infection in Japan has not been investigated. We evaluated the status of H. pylori infection in a Japanese general population using large-scale resident-register-based sampling.

METHODS

All 6069 adults in a rural town and 6000 adults in two urban cities (3000 each), selected by register-based random sampling, were enrolled in our health check-up program. Antibody titers against Helicobacter pylori (cut-off value was 3 U/mL by Eiken E-plate) were evaluated, and subjects with a positive result were encouraged to undergo further examinations.

RESULTS

A total of 1586 subjects participated in serum sampling. The overall prevalence of H. pylori infection was 40.0% (634/1586), and it increased with age both in rural and urban areas. Although the overall positive rate was higher in the rural area (49.4%) than in the urban areas (35.6 and 32.3%), there was no difference in H. pylori status of younger subjects between the two areas. Among 634 patients with a positive titer, 374 (59.0%) underwent further examinations including endoscopic examination, and 180/634 (28.4%) patients received eradication therapy. Gastric neoplasms (three adenocarcinomas and one adenoma) were found in our screening program.

CONCLUSION

We clarified population-based random sampling data of H. pylori infection in a Japanese general population. In younger subjects, a decrease in the prevalence of H. pylori infection was confirmed both in rural and urban areas. This provides basic information for establishing a strategy to reduce gastric cancer deaths.

Gastric Cancer Screening in Japan: A Narrative Review

Gastric cancer is the second leading cause of cancer incidence in Japan, although gastric cancer mortality has decreased over the past few decades. This decrease is attributed to a decline in the prevalence of H. pylori infection. Radiographic examination has long been performed as the only method of gastric screening with evidence of reduction in mortality in the past. The revised 2014 Japanese Guidelines for Gastric Cancer Screening approved gastric endoscopy for use in population-based screening, together with radiography. While endoscopic gastric cancer screening has begun, there are some problems associated with its implementation, including endoscopic capacity, equal access, and cost-effectiveness. As H. pylori infection and atrophic gastritis are well-known risk factors for gastric cancer, a different screening method might be considered, depending on its association with the individual’s background and gastric cancer risk. In this review, we summarize the current status and problems of gastric cancer screening in Japan. We also introduce and discuss the results of gastric cancer screening using H. pylori infection status in Hoki-cho, Tottori prefecture. Further, we review risk stratification as a system for improving gastric cancer screening in the future.

Association between dental caries and Helicobacter pylori infection in Japanese adults: A cross-sectional study

Helicobacter pylori (H. pylori) is widely known as a cause of gastric disorders. Presence of H. pylori in dental pulp has been reported. Dental caries may influence the presence or absence of systemic H. pylori infection by serving as a source of H. pylori. In this cross-sectional study, we examined whether H. pylori infection in blood were associated with dental caries in Japanese adults. The participants were 752 individuals (513 males and 239 females, mean age 53.8 years) who underwent both H. pylori testing (H. pylori antibody test and pepsinogen test) and dental checkups at the Asahi University Hospital Human Health Center between April 2018 and March 2019. Those diagnosed as positive for H. pylori antibody test or positive for serum pepsinogen test as H. pylori test in the human health checkup were judged as those with H. pylori infection in the blood. In our study, 83 participants (11%) were determined to be infected with H. pylori in the blood. The proportion of those with decayed teeth was higher in participants with H. pylori infection in blood than in those without H. pylori infection in blood (p< 0.001). The logistic analysis showed that presence of H. pylori infection in blood was positively associated with those with decayed teeth (OR, 5.656; 95% CI, 3.374 to 9.479) after adjusting for age, gender, gastric disease, regular dental checkups, antibiotic medication history, and decayed teeth. Furthermore, the proportion of H. pylori infection in blood increased according to number of decayed teeth (p< 0.001). The results indicate that H. pylori infection in blood were associated with decayed teeth. Untreated dental caries may have an impact on systemic H. pylori infection.

Higher proportions of a healthy gastric mucosa in healthy Japanese adults with later birth year: analysis of 41 957 participants

BACKGROUND

In Japan, most gastric cancers are associated with gastric mucosal atrophy caused by chronic infection with Helicobacter pylori (H. pylori). Recognizing the condition of the gastric mucosa and determining the infection status of H. pylori are important for predicting the individual risk of gastric cancer. This study aimed to determine the proportion of Japanese adults with a healthy gastric mucosa (without H. pylori infection) among 12 birth-year groups encompassing 1935-1990 by morphological images.

METHODS

The gastric mucosa was classified as healthy or having gastritis based on routine double-contrast upper gastrointestinal barium X-ray radiography. The participants included 41 957 healthy Japanese adults. Serum or urine H. pylori antibody levels were also assessed.

RESULTS

In total, 25 424 participants had healthy mucosa without a history of H. pylori eradication. The proportions of participants with a healthy mucosa by birth year were 19.8% (57/288), 27.1% (306/1128), 32.4% (569/1756), 37.6% (1808/4811), 49.2% (3207/6522), 60.1% (3966/6550), 71.2% (5224/7342), 77.2% (5114/6624), 80.6% (3342/4149), 85.0% (1404/1652), 85.3% (302/354) and 94.7% (125/132) in 1935, 1940, 1945, 1950, 1955, 1960, 1965, 1970, 1975, 1980, 1985 and after 1990, respectively (P for trend <0.01). All the participants with a healthy mucosa showed negative results in the H. pylori antibody tests.

CONCLUSIONS

The proportion of participants with normal gastric mucosa linearly increased with the birth years. The prevalence of morphologically healthy gastric mucosa could have consistently increased with decreasing prevalence of H. pylori infection.

Age of eradication and failure rates of clarithromycin-containing triple therapy for Helicobacter pylori: A 15-year population-based study

BACKGROUND

Failure rates of clarithromycin-containing triple therapy for H. pylori are rising. To determine the trend of failure rates of clarithromycin-containing triple therapy in different age groups in Hong Kong over the past 15 years.

MATERIALS AND METHODS

This is a population-based retrospective age-period-cohort study involving all adult H. pylori-infected patients who had received the first course of clarithromycin-containing triple therapy in 2003-2017. Failed eradication was identified by the need of retreatment within 2 years of eradication. Logistic regression model was used to characterize the risk of retreatment.

RESULTS

113,526 H. pylori-infected patients were included. The overall failure rate increased from 4.83% in 2003 to 10.2% in 2016 (p for linear trend <0.001). When stratified by age of eradication, patients 75 years or above had the lowest retreatment rate of 5.11%, which progressively increased in younger patients (60-74 years: OR 1.26, 95% CI 1.15-1.38; 45-59 years: OR 1.36, 95% CI 1.24-1.48; 18-44 years: OR 1.55, 95% CI 1.41-1.69). The results remained consistent when stratified by year of birth, and period of eradication. Other risk factors for retreatment included female (OR 1.24, 95% CI 1.18-1.30), triple therapy containing metronidazole (OR 2.30, 95% CI 2.12-2.50), and shorter duration of therapy (10 days: OR 0.88, 95% CI 0.79-0.97; 14 days: OR 0.67, 95% CI 0.58-0.77 vs 7 days).

CONCLUSIONS

While failure rates of clarithromycin-containing triple therapy progressively increased over the past 15 years, the failure rate was particularly high among younger patients, which could undermine the potential benefits of early H. pylori eradication.

Economic and health impacts of Helicobacter pylori eradication strategy for the treatment of peptic ulcer disease: A cost-effectiveness analysis

BACKGROUND

Most peptic ulcer cases are associated with Helicobacter pylori (H. pylori) infection or the use of nonsteroidal anti-inflammatory drugs (NSAIDs). H. pylori eradication therapy is recommended for the treatment of H. pylori-positive peptic ulcers. We aimed to assess and validate the cumulative economic and health effects of H. pylori eradication strategy for the treatment of peptic ulcers compared with PPI therapy strategy.

MATERIALS AND METHODS

We developed a cohort state-transition model for H. pylori eradication strategy and PPI therapy strategy over a lifetime horizon from a healthcare payer perspective. We targeted two hypothetical cohorts of H. pylori-positive patients with gastric and duodenal ulcers 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, ulcer recurrence cases, and ulcer-associated deaths. One-way and probabilistic sensitivity analyses were conducted to assess the impact of uncertainty.

RESULTS

In the base-case analysis, H. pylori eradication strategy was less costly with greater benefits than PPI therapy strategy in all age groups. Cost-effectiveness was not sensitive to any variables in all age groups. Sensitivity analyses showed strong robustness of the results. From 2000 to 2020, H. pylori eradication strategy saved US$14.07 billion over a lifetime, increased 8.65 million QALYs and 1.23 million LYs over a lifetime, and prevented 551,298 ulcer recurrence cases and 59,465 ulcer-associated deaths, compared with PPI therapy strategy.

CONCLUSIONS

H. pylori eradication strategy not only has contributed significantly to preventing ulcer recurrence and reducing ulcer-associated deaths but also has resulted in great cost savings. All over the world, H. pylori eradication strategy is likely to have yielded a comparable magnitude of economic and health benefits, depending on the epidemiology of H. pylori-related peptic ulcers and the healthcare environment in each country.

Risk factors for gastric cancer in Japan in the 2010s: a large, long-term observational study

BACKGROUND

The numbers of Helicobacter pylori (HP)-infected individuals and deaths due to gastric cancer are decreasing in Japan. We aimed to determine whether the serological test for chronic gastritis (the ABC method) is still useful for gastric cancer risk stratification in the 2010s and to analyze risk factors for developing gastric cancer in Japan.

METHODS

In this prospective study, we monitored 20773 individuals for the incidence of gastric cancer from 2010 to 2019. The relationships between blood sampling results, physical examination, and lifestyle in 2010 and the cumulative incidence of gastric cancer were analyzed.

RESULTS

A total of 19343 participants who met the study criteria were analyzed. Overall, 0.08% of participants in group A (9/11717), 0.63% in group B (28/4452), 2.05% in group C (43/2098), 1.52% in group D (1/66), and 0.30% in group E (3/1010) developed gastric cancer. Cox hazard analysis showed that age ≥ 50 years; groups B, C, and D according to the ABC method; and current smoking habits were independent risk factors for gastric cancer. The hazard ratios (HRs) of the incidence of gastric cancer were 6.7 in group B and 21.7 in groups C and D, while the HRs of group E was 2.8, which was not significantly different from that of group A. The incidence of gastric cancer was not statistically significantly different between those with and without successful HP eradication in groups B, C, and D during follow-up.

CONCLUSIONS

The ABC method was still useful for gastric cancer risk stratification in the 2010s.

Prevalence of Helicobacter pylori infection in China: A systematic review and meta-analysis

BACKGROUND AND AIM

Helicobacter pylori (H. pylori) infection rates have been changing with different populations and geographic areas. We systematically evaluated the longitudinal trends in H. pylori prevalence in China over the past decades.

METHODS

We performed a systematic review of literature reporting the prevalence of H. pylori infection in mainland China from 1990 to 2019 in the PubMed and China National Knowledge Infrastructure databases. We conducted a meta-analysis of qualified studies using a random effects model to estimate the pooled prevalence with a 95% confidence interval (95%CI).

RESULTS

A total of 412 eligible studies with 1 377 349 subjects were included. The pooled H. pylori prevalence was 44.2% (95%CI: 43.0-45.5%) in mainland China, with an estimated 589 million individuals infected with H. pylori. The prevalence was relatively high in the Northwest (51.8%, 95%CI: 47.5-56.1%), East (47.7%, 95%CI: 45.4-50.0%), and Southwest China (46.6%, 95%CI: 42.1-51.1%). The prevalence significantly decreased from 58.3% (95%CI: 50.7-65.5%) in the period 1983-1994 to 40.0% (95%CI: 38.2-41.8%) in the period 2015-2019. The prevalence increased with age, ranging from 28.0% (95%CI: 23.9-32.5%) in children and adolescents to 46.1% (95%CI: 44.5-47.6%) in adults.

CONCLUSION

Although the burden of H. pylori infections is still huge in China, the infection rate has been decreasing over the past decades. Targeted H. pylori eradication strategies may be considered in areas or populations with a high incidence of gastric cancer.

Burden of cancer attributable to modifiable factors in Japan in 2015

The This study estimated the cancer burden attributable to modifiable factors in Japan in 2015 using the best available epidemiological evidence and a standard methodology. We selected the following factors for inclusion in the estimates, namely tobacco smoking (active smoking and secondhand smoking), alcohol drinking, excess bodyweight, physical inactivity, infectious agents (Helicobacter pylori, hepatitis C virus, hepatitis B virus, human papilloma virus, Epstein-Barr virus, and human T-cell leukemia virus type 1), dietary intake (highly salted food, fruit, vegetables, dietary fiber, red meat, processed meat), exogenous hormone use, never breastfeeding and air pollution, given that these were considered modifiable, in theory at least. We first estimated the population attributable fraction (PAF) of each cancer attributable to these factors using representative relative risks of Japanese and the prevalence of exposures in Japanese around 2005, in consideration of the 10-year interval between exposure and cancer outcomes. Using nationwide cancer incidence and mortality statistics, we then estimated the attributable cancer incidence and mortality in 2015. We finally obtained the PAF for site-specific and total cancers attributable to all modifiable risk factors using this formula, with statistical consideration of the effect of overlap between risk factors. The results showed that 35.9% of all cancer incidence (43.4% in men and 25.3% in women) and 41.0% of all cancer mortality (49.7% in men and 26.8% in women) would be considered preventable by avoidance of these exposures. Infections and active smoking followed by alcohol drinking were the greatest contributing factors to cancer in Japan in 2015.

Lifetime incidence risk for gastric cancer in the Helicobacter pylori-infected and uninfected population in Japan: A Monte Carlo simulation study

Helicobacter pylori (H. pylori) infection is considered the leading cause of gastric cancer. Gastric cancer is currently a common cancer with high incidence and mortality rates, but it is expected that the incidence rate will gradually decrease as the H. pylori infection prevalence decreases in the future. When evaluating the effectiveness of gastric cancer prevention strategies, it is essential to note the differences in long‐term cumulative risks between H. pylori‐infected and uninfected populations, but this has not yet been precisely evaluated. In our study, we aimed to estimate the cumulative incidence risks of developing gastric cancer from birth to 85 years among H. pylori‐infected and uninfected populations by using population‐based cancer registry data and birth year‐specific H. pylori infection prevalence rates. Death from gastric cancer and other causes of death were considered in the estimations of the adjusted cumulative incidence risks stratified by sex and H. pylori infection status. After performing 5000 Monte Carlo simulations with repeated random sampling using observed cancer incidence in selected three prefectures (Fukui, Nagasaki, Yamagata) of prefectural population‐based cancer registry in Japan, the mean adjusted cumulative incidence risk for gastric cancer in the H. pylori‐infected population was 17.0% for males and 7.7% for females and 1.0% for males and 0.5% for females in the uninfected population. These results calculated with Japanese cancer registry data may be useful in considering and evaluating future prevention strategies for gastric cancer in Japan.

What's new?

Helicobacter pylori infection is considered the leading cause of gastric cancer. This study estimated the cumulative incidence risk for gastric cancer from birth to 85 years of age, stratified by H. pylori infection status, for the first time in Japan. The cumulative risk among H. pylori‐infected individuals was 17.0% in males and 7.7% in females, after adjusting for gastric cancer incidence and other causes of death. The cumulative risk in the population without H. pylori infection was low. These results offer essential information for future cost‐effectiveness and cost‐benefit analyses and new gastric cancer prevention programs in Japan.

International comparison of trends in cancer mortality: Japan has fallen behind in screening-related cancers

While the age-standardized mortality rate in Japan is decreasing for all cancers as a whole, this is not the case for some major site-specific cancers. We descriptively compared trends in all-cancer and site-specific cancer mortality in Japan and selected countries. Data on age-standardized cancer mortality rates in six countries (Japan, the USA, the UK, Canada, Australia and the Republic of Korea) in 1980-2016 were obtained from the World Health Organization mortality database. While stomach and liver cancer mortality rates in Japan and Korea were initially much higher than those in non-Asian countries, they have rapidly decreased over the long term. By contrast, colorectal, pancreatic and cervical cancer mortality rates in Japan, which were initially lower than those in other countries, have increased such that they are now similar or higher than the rates in non-Asian countries. For male lung cancer, Japan's initially lower mortality rate is now comparable to that in non-Asian countries as a result of slower decline. Meanwhile, the mortality rate of female breast cancer in Japan and Korea has increased and is nearing the rates observed in non-Asian countries, which by contrast have shown a steady decrease. Thus, while Japan has been successful in reducing the burden of stomach and liver cancers, it is falling behind in reducing the mortality rate of screening-related cancers such as colorectal, female breast and cervical cancers. Control measures for these cancers need to be strengthened.

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.

Efficacy of second-line regimens for Helicobacter pylori eradication treatment: a systemic review and network meta-analysis

Background

Current guidelines recommend bismuth-containing quadruple therapy (BQT) and quinolone-containing therapy after failure of first-line Helicobacter pylori eradication therapy. However, the optimum regimen of second-line eradication therapy remains elusive. We conducted a network meta-analysis to compare the relative efficacy of 16 second-line H. pylori eradication regimens.

Methods

Three major bibliographic databases were reviewed to enrol relevant randomised controlled trials between January 2000 and September 2018. Network meta-analysis was conducted by STATA software and we performed subgroup analysis in countries with high clarithromycin resistance and high levofloxacin resistance, and in patients with documented failure of first-line triple therapy.

Results

Fifty-four studies totalling 8752 participants who received 16 regimens were eligible for analysis. Compared with a 7-day BQT, use of probiotic add-on therapy during, before, and after second-line antibiotic regimens, quinolone-based sequential therapy for 10–14 days, quinolone-based bismuth quadruple therapy for 10–14 days, bismuth quadruple therapy for 10–14 days, and quinolone-based triple therapy for 10–14 days were significantly superior to the other regimens. Subgroup analysis of countries with high clarithromycin resistance and high levofloxacin resistance revealed that the ranking of second-line eradication regimens was distributed similarly in each group, as well as in patients with failure of first-line triple therapy.

Conclusion

We conducted a detailed comparison of second-line H. pylori regimens according to different antibiotic resistance rates and the results suggest alternative treatment choices with potential benefits beyond those that could be achieved using salvage therapies recommended by guidelines.

Lifestyles, genetics, and future perspectives on gastric cancer in east Asian populations

The prevalence of gastric cancer (GC) differs among regions worldwide, with the highest occurrence in east Asia. Thus, its etiology, with respect to ethnic background, environmental factors, and lifestyles, is also thought to differ essentially. In addition, etiology of GC is speculated to be changing due to the recent decrease in the Helicobacter pylori (H. pylori) infection in Japan. State-of-the-art somatic/germline cancer genomics has clarified the etiologies of gastric carcinogenesis. In this review article, we summarize past and present milestones in our understanding of GC achieved through genomic approaches, including a recent report that revealed higher-than-expected frequencies of GCs attributed to east Asian-specific germline variants in ALDH2 or CDH1 in combination with lifestyles. Based on this updated knowledge, we also discuss the possible impact of and high-risk approaches for GCs in the upcoming "H. pylori-negative era."

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.

Similarity and difference in the characteristics of eosinophilic esophagitis between Western countries and Japan

Over the past two decades, the incidence and prevalence of eosinophilic esophagitis (EoE) have risen rapidly, especially in Western countries, with cases in Japan also showing a gradual increase in recent years. However, similarities and differences regarding the characteristics of EoE between Western countries and Japan remain to be clearly elucidated. The current clinical guidelines for diagnosis include symptoms related to esophageal dysfunction and dense eosinophilic infiltration in the esophageal epithelium. Most affected patients in Japan are diagnosed incidentally during a medical health check-up and asymptomatic cases with typical endoscopic findings suggestive of EoE are frequently encountered. Clinical characteristics of EoE in Japanese are similar to those seen in Western populations. The predominant symptom is dysphagia, with food impaction extremely rare in Japanese cases. Linear furrows are the most frequently reported characteristic endoscopic finding, while an esophageal stricture or narrow caliber is rarely observed. Treatment strategies for EoE include drugs, dietary restrictions, and endoscopic dilation when the disease is advanced with stricture formation. Although single therapy using a proton-pump inhibitor has been shown to achieve symptomatic and histological response in the majority of patients in Japan, no prospective randomized control studies that evaluated drug or elimination diet therapy have been presented. Overall, EoE has similar clinical characteristics between Japanese and Western populations, while disease severity seems to be milder in Japan. Additional studies are necessary to determine genetic factors, natural history of the disease, and treatment efficacy of drugs and elimination diet as compared to Western populations.

Public Health Interventions for Gastric Cancer Control

Despite its generally decreasing trend in incidence, gastric cancer remains the fifth-most common cancer worldwide. Gastric cancer has substantially declined over the past century, thanks to decreases in risk factors such as Helicobacter pylori infection, tobacco smoking, and salt-preserved food intake. These decreases have resulted from natural interventions and population-based intervention strategies. H pylori eradication for infected patients has potential as a prevention strategy for those at high risk, but warrants a longer follow-up period. The ongoing increase in obesity prevalence may cause an increase in cardia gastric cancer, especially in Western populations, and should be carefully monitored.

Updated Trends in Cancer in Japan: Incidence in 1985-2015 and Mortality in 1958-2018-A Sign of Decrease in Cancer Incidence

Background

Unlike many North American and European countries, Japan has observed a continuous increase in cancer incidence over the last few decades. We examined the most recent trends in population-based cancer incidence and mortality in Japan.

Methods

National cancer mortality data between 1958 and 2018 were obtained from published vital statistics. Cancer incidence data between 1985 and 2015 were obtained from high-quality population-based cancer registries maintained by three prefectures (Yamagata, Fukui, and Nagasaki). Trends in age-standardized rates (ASR) were examined using Joinpoint regression analysis.

Results

For males, all-cancer incidence increased between 1985 and 1996 (annual percent change [APC] +1.1%; 95% confidence interval [CI], 0.7–1.5%), increased again in 2000–2010 (+1.3%; 95% CI, 0.9–1.8%), and then decreased until 2015 (−1.4%; 95% CI, −2.5 to −0.3%). For females, all-cancer incidence increased until 2010 (+0.8%; 95% CI, 0.6–0.9% in 1985–2004 and +2.4%; 95% CI, 1.3–3.4% in 2004–2010), and stabilized thereafter until 2015. The post-2000 increase was mainly attributable to prostate in males and breast in females, which slowed or levelled during the first decade of the 2000s. After a sustained increase, all-cancer mortality for males decreased in 1996–2013 (−1.6%; 95% CI, −1.6 to −1.5%) and accelerated thereafter until 2018 (−2.5%; 95% CI, −2.9 to −2.0%). All-cancer mortality for females decreased intermittently throughout the observation period, with the most recent APC of −1.0% (95% CI, −1.1 to −0.9%) in 2003–2018. The recent decreases in mortality in both sexes, and in incidence in males, were mainly attributable to stomach, liver, and male lung cancers.

Conclusion

The ASR of all-cancer incidence began decreasing significantly in males and levelled off in females in 2010.

Current Prevalence of Oral Helicobacter pylori among Japanese Adults Determined Using a Nested Polymerase Chain Reaction Assay

In Japan, gastric Helicobacter pylori infection prevalence has markedly decreased with socioeconomic development. We aimed to investigate the prevalence of oral H. pylori in Japanese adults in 2020 by sex, age, sampling site, and medical history. Unstimulated saliva, supragingival biofilm, and tongue coating were obtained from 88 subjects-with no complaints of upper digestive symptoms-attending a dentist's office for dental check-up or disorders. Supragingival biofilm was collected from the upper incisors, lower incisors, upper right molars and lower left molars to analyze the characteristic distribution. Oral H. pylori was detected using nested polymerase chain reaction. Oral H. pylori prevalence did not statistically differ by sex or age. Supragingival biofilm (30.7%) was the most common oral H. pylori niche; it was also detected in 4.5% of saliva and 2.3% of tongue samples. The lower incisor was the most common site among the supragingival biofilm samples, followed by the upper incisors, lower left molars, and upper right molars. Oral H. pylori DNA was frequently detected in patients with a history of gastric H. pylori infection. Oral H. pylori has a characteristic distribution independent of sex and age, suggesting that it is part of the normal microflora in the adult oral cavity.

Risk factors for esophageal iodine-unstained lesions and changing trends among Japanese alcohol-dependent men (2003-2018)

Globally, a decreasing incidence of male esophageal squamous cell carcinoma (ESCC) has been observed in recent decades. We evaluated the determinants of esophageal distinct iodine-unstained lesions (DIULs), high-cancer-risk lesions and ESCC, among 3858 Japanese alcohol-dependent men (40-79 years) who underwent chromoendoscopic screening between 2003 and 2018. The initial screening detected DIULs ≥ 5 mm in 541 patients (dysplasia in 319 and SCC in 129) and multiple DIULs in 640. The detection rates for DIULs and chronic atrophic gastritis (CAG), pack-years, and the mean corpuscular volume (MCV) decreased over the course of the study period, while the detection of hiatal hernia and/or columnar-lined esophagus (HH/CLE) and the carriers of inactive heterozygous aldehyde dehydrogenase-2 (ALDH2, rs671) increased. Multiple logistic regression analyses showed that an older age, larger number of pack-years, smaller body mass index, larger MCV, presence of a slow-metabolizing alcohol dehydrogenase-1B genotype (rs1229984), presence of an inactive heterozygous ALDH2 genotype, and more advanced degree of CAG increased the odds ratios (ORs) for DIULs, while the 2008-2013 and 2014-2018 screening periods had lower ORs for DIULs than the 2003-2007 screening period. The presence of HH/CLE decreased the OR for multiple DIULs and was associated with a more proximal location of ESCC. In conclusion, the detection of DIULs in an alcohol-dependent population decreased between 2003 and 2018. In addition to reported determinants of ESCC, CAG and HH/CLE were associated with the risk of DIULs. Enigmatically, however, the decline in the detection of DIULs was not adequately explained by these factors and warrants further research.

An age-period-cohort analysis of mortality rates for stomach, colorectal, liver, and lung cancer among prefectures in Japan, 1999-2018

BACKGROUND

Although change in the birth cohort effect on cancer mortality rates is known to be highly associated with the decreasing rates of age-standardized cancer mortality rates in Japan, the differences in the trends of cohort effect for representative cancer types among the prefectures remain unknown. This study aimed to investigate the differences in the decreasing rate of cohort effects among the prefectures for representative cancer types using age-period-cohort (APC) analysis.

METHODS

Data on stomach, colorectal, liver, and lung cancer mortality for each prefecture and the population data from 1999 to 2018 were obtained from the Vital Statistics in Japan. Mortality data for individuals aged 50 to 79 years grouped in 5-year increments were used, and corresponding birth cohorts born 1920-1924 through 1964-1978 were used for analysis. We estimated the effects of age, period, and cohort on each type of mortality rate for each prefecture by sex. Then, we calculated the decreasing rates of cohort effects for each prefecture. We also calculated the mortality rate ratio of each prefecture compared with all of Japan for cohorts using the estimates.

RESULTS

As a result of APC analysis, we found that the decreasing rates of period effects were small and that there was a little difference in the decreasing rates among prefectures for all types of cancer among both sexes. On the other hand, there was a large difference in the decreasing rates of cohort effects for stomach and liver cancer mortality rates among prefectures, particularly for men. For men, the decreasing rates of cohort effects in cohorts born between 1920-1924 and 1964-1978 varied among prefectures, ranging from 4.1 to 84.0% for stomach cancer and from 20.2 to 92.4% for liver cancers, respectively. On the other hand, the differences in the decreasing rates of cohort effects among prefectures for colorectal and lung cancer were relatively smaller.

CONCLUSIONS

The decreasing rates of cohort effects for stomach and liver cancer varied widely among prefectures. It is possible that this will influence cancer mortality rates in each prefecture in the future.

Inverse time trends of peptic ulcer and reflux esophagitis show significant association with reduced prevalence of Helicobacter pylori infection

INTRODUCTION

Recent prevalence and trends of gastric/duodenal ulcer (GU/DU) and reflux esophagitis (RE) are inadequate.

METHODS

We reviewed the records of consecutive 211,347 general population subjects from 1991 to 2015.

RESULTS

During the 25 years, the prevalence of GU and DU has gradually decreased (from 3.0% to 0.3% and from 2.0% to 0.3%) whereas that of RE has markedly increased (from 2.0% to 22%). The prevalence of Helicobacter pylori (HP) infection has decreased from 49.8% (in 1996) to 31.2% (in 2010). Multivariable logistic regression analyses demonstrated that HP infection was positively associated with GU/DU and negatively associated with RE with statistical significance. The panel data analyses showed that reduced rate of HP infection is proportionally correlated with decrease of GU/DU and inversely correlated with increase of RE. It is further suggested other latent factors should be important for changed prevalence of these three acid-related diseases. Age-period-cohort analysis indicated the significant association of older age, male gender, and absence of HP infection with RE.

CONCLUSIONS

The prevalence of GU and DU has gradually decreased whereas that of RE has markedly increased in Japan. Inverse time trends of peptic ulcer and reflux esophagitis are significantly associated with reduced prevalence of HP infection. KEY MESSAGES The prevalence of gastric and duodenal ulcer has gradually decreased whereas that of reflux esophagitis has markedly increased in Japan. The prevalence of Helicobacter pylori infection in Japan has greatly decreased from 49.8% to 31.2% during the 14 years (from 1996 to 2010). Inverse time trends of peptic ulcer and reflux esophagitis are associated with reduced prevalence of Helicobacter pylori infection with statistical significance.

Population-Based Analysis of Differences in Gastric Cancer Incidence Among Races and Ethnicities in Individuals Age 50 Years and Older

BACKGROUND & AIMS

There are racial and ethnic differences in the incidence of gastric adenocarcinoma worldwide and in the US. Based on a decision analysis, screening for noncardia gastric adenocarcinoma might be cost-effective for non-White individuals 50 years or older. However, a lack of precise, contemporary information on gastric adenocarcinoma incidence in specific anatomic sites for this age group has impeded prevention and early detection programs in the US. We aimed to estimate the differences in gastric adenocarcinoma incidence in specific anatomic sites among races and ethnicities in individuals 50 years or older.

METHODS

We analyzed California Cancer Registry data from 2011 through 2015 to estimate incidences of gastric adenocarcinoma in specific anatomic sites for non-Hispanic White (NHW), non-Hispanic Black, Hispanic, and the 7 largest Asian American populations. We calculated the differential incidence between non-White groups and NHW using incidence rate ratios and 95% confidence intervals (CIs).

RESULTS

Compared with NHW subjects, all non-White groups had significantly higher incidences of noncardia gastric adenocarcinoma; the incidence was highest among Korean American men 50 years and older (70 cases per 100,000). Compared with NHW subjects 50 years and older, the risk of noncardia gastric adenocarcinoma was 1.8-fold (95% CI, 1.37-2.31) to 7.3-fold (95% CI, 5.73-9.19) higher in most non-White groups and 12.0-fold (95% CI, 9.96-14.6) to 14.5-fold (95% CI, 12.5-16.9) higher among Korean American men and women 50 years and older, respectively. Compared with NHW men 50 years and older, all non-White men, except Japanese and Korean American men, had a significantly lower risk of cardia gastric adenocarcinoma.

CONCLUSIONS

We identified several-fold differences in incidences of gastric adenocarcinoma in specific anatomic sites among racial and ethnic groups, with significant age and sex differences. These findings can be used to develop targeted risk reduction programs for gastric adenocarcinoma.

Prediction of true Helicobacter pylori-uninfected status using a combination of age, serum antibody and pepsinogen: Logistic regression analysis

Introduction

To prevent gastric cancer, it is important to accurately determine the presence of Helicobacter pylori (HP) infection. However, correctly identifying HP-uninfected individuals is difficult when using the combination of HP antibody and pepsinogen (PG).

Objective

The aim of this study was to discriminate true HP-uninfected individuals from others without the need for endoscopic examination.

Methods

A total of 684 subjects with no history of HP eradication who underwent a medical checkup at our hospital were enrolled. The “true uninfected individuals” were determined by a negative stool antigen test and no endoscopic findings of HP-associated gastritis. HP antibody was measured by the latex immunoassay method. Logistic regression analysis using a combination of noninvasive parameters was performed to develop a formula for predicting true uninfected individuals.

Results

A total of 528 subjects were classified as true uninfected individuals. Logistic regression analysis showed that statistically significant factors for true uninfected individuals were age (p < 0.001), HP antibody (p <0.001), PGI (p <0.001), and PGII (p = 0.012). The areas under the curve (AUCs) for true uninfected individuals were the highest (0.944) upon applying the prediction formula including four parameters: age, HP antibody, PGI, and PGII. Both the sensitivity and the specificity of the four-parameter prediction formula were higher than those of the traditional three-parameter model using HP antibody, PGI, and PGI/II ratio (sensitivity: 93.2% vs. 86.6% and specificity: 88.5% vs. 82.7%).

Conclusions

Our findings suggest that a model with a combination of four noninvasive parameters is useful for predicting true HP-uninfected individuals without the need for endoscopic examination.

Effect and cost-effectiveness of national gastric cancer screening in Japan: a microsimulation modeling study

BACKGROUND

A national endoscopic screening program for gastric cancer was rolled out in Japan in 2015. We used a microsimulation model to estimate the cost-effectiveness of current screening guidelines and alternative screening strategies in Japan.

METHODS

We developed a microsimulation model that simulated a virtual population corresponding to the Japanese population in risk factor profile and life expectancy. We evaluated 15 endoscopic screening scenarios with various starting ages, stopping ages, and screening intervals. The primary outcomes were quality-adjusted life-years (QALYs), costs, and incremental cost-effectiveness ratio. Cost-effective screening strategies were determined using a willingness-to-pay threshold of $50,000 per QALY gained. One-way sensitivity and probabilistic sensitivity analyses were done to explore model uncertainty.

RESULTS

Using the threshold of $50,000 per QALY, a triennial screening program for individuals aged 50 to 75 years was the cost-effective strategy, with an incremental cost-effectiveness ratio of $45,665. Compared with no endoscopic screening, this strategy is predicted to prevent 63% of gastric cancer mortality and confer 27.2 QALYs gained per 1000 individuals over a lifetime period. Current screening guidelines were not on the cost-effectiveness efficient frontier. The results were robust on one-way sensitivity analyses and probabilistic sensitivity analysis.

CONCLUSIONS

This modeling study suggests that the endoscopic screening program in Japan would be cost-effective when implemented between age 50 and 75 years, with the screening repeated every 3 years. These findings underscore the need for further evaluation of the current gastric cancer screening recommendations.

Helicobacter pylori test-and-treat strategy for second-year junior high school students aimed at the prevention of gastric cancer in Takatsuki City

BACKGROUND

More than 90% of gastric cancer cases are caused by Helicobacter pylori infections. To prevent gastric cancer, an H pylori test-and-treat strategy targeting young people has been implemented in various places in Japan. In this study, we evaluated the effectiveness of an H pylori test-and-treat strategy for second-year junior high school students in Takatsuki City.

MATERIALS AND METHODS

In 2014-2017, a urine-based H pylori test was used for initial screening. The final infection status was determined by a ¹³ C-urea breath test (¹³ C-UBT). Successful H pylori eradication was confirmed by ¹³ C-UBT 3 months after treatment. First-line eradication therapy was changed from 10 mg of rabeprazole, 750 mg of amoxicillin, and 200 mg of clarithromycin twice daily for 7 days in 2014 to 20 mg of vonoprazan, 750 mg of amoxicillin, and 200 mg of clarithromycin twice daily for 7 days in 2015-2017. Second-line eradication therapy included 10 mg of rabeprazole, 750 mg of amoxicillin, and 250 mg of metronidazole twice daily for 7 days.

RESULTS

In total, 8067 of 13 055 students participated this project and 206 students were diagnosed with H pylori infection. The success rate of first-line therapy was 45.9% in 2014 and 83.8% after the revised first-line therapy was administered. The final eradication rate was 98.5%. There were no severe side effects.

CONCLUSION

Our results support the use of the H pylori test-and-treat strategy for junior high school students as a safe approach for the prevention of gastric cancer. H pylori eradication therapy with vonoprazan could be a standard therapy in children.