Effect of age on the relationship between gastric cancer and Helicobacter pylori. Tokyo Research Group of Prevention for Gastric Cancer

Endoscopic Features of Undifferentiated-Type Early Gastric Cancer in Patients with Helicobacter pylori-Uninfected or -Eradicated Stomachs: A Comprehensive Review

Since the indications for endoscopic submucosal dissection have been expanded to include undifferentiated-type early gastric cancers, improvements in preoperative diagnostic ability have been an area of research. There are also concerns about the impact on the diagnosis of Helicobacter pylori infection. Based on our previous studies, in undifferentiated-type early gastric cancers, magnifying endoscopy with narrow-band imaging is useful for delineating the demarcation regardless of the tumor size. Additionally, inflammatory cell infiltration appears to be a cause of misdiagnosis, suggesting that the resolution of inflammation could contribute to the accurate diagnosis of demarcations. As such, the accuracy of demarcation in eradicated and uninfected cases is higher than that in non-eradicated cases. The common features of the endoscopic findings were discoloration under white-light imaging and a predominance of sites in the lower and middle regions. The uninfected group was characterized by smaller tumor size, flat type, more extended intervening parts in magnifying endoscopy with narrow-band imaging, and pure signet ring cell carcinoma. In contrast, the eradication and non-eradication groups were characterized by larger tumor size, depressed type, and wavy microvessels in magnifying endoscopy with narrow-band imaging. In this comprehensive review, as described above, we discuss the diagnosis of demarcation of undifferentiated-type early gastric cancers, undifferentiated-type early gastric cancers that developed following H. pylori eradication, and H. pylori-uninfected undifferentiated-type early gastric cancers, with a focus on studies with self-examination and endoscopic findings and describe the future direction.

Menstrual and Reproductive Factors for Gastric Cancer in Postmenopausal Women: The 2007-2020 Korea National Health and Nutrition Examination Survey

Globally, the incidence of gastric cancer is lower in women than in men. It is thought that menstrual and reproductive factors may be related to their lower incidence of gastric cancer. This cross-sectional study examined menstrual, reproductive, and other factors in 20,784 postmenopausal women from the 2007-2020 Korea National Health and Nutrition Examination Survey (KNHANES). A univariate logistic regression analysis was performed, and then a multivariate logistic regression analysis for significant factors in the univariate analysis was conducted. In the multivariate logistic regression analysis, the age at menarche (odds ratio [OR] 1.08, 95% confidence interval [CI] 1.00-1.06, p = 0.035) and myocardial infarction (OR 2.43, 95% CI 1.05-5.62, p = 0.026) showed a significant association with increased incidence of gastric cancer. The age at menopause (OR 0.97, 95% CI 0.95-1.00, p = 0.03), the age at the first childbirth (OR 0.93, CI 0.89-0.97, p = 0.007), and the experience of alcohol consumption (OR 0.68, 95% CI 0.5-0.91, p = 0.003) showed a significant association with a decreased incidence of gastric cancer. Late menarche, early menopause, early aged first childbirth, and myocardial infarction are estimated to be risk factors for gastric cancer in postmenopausal Korean women.

Relative risk of gastric cancer between those with and without Helicobacter pylori infection history in Japan

Background and Aim

The causal relationship between Helicobacter pylori (H. pylori) infection and gastric cancer has been established. Although the magnitude of the carcinogenic effect of H. pylori is the next concern, it has not been sufficiently evaluated in Japan. Spontaneous disappearance of H. pylori infection may have provoked underestimation of the carcinogenic effect of the infection. To reduce the influence, a comparison should be carried out between subjects with and without the infection history. Cutoff values of H. pylori antibody lower than the manufacturer's recommendation are known to be more appropriate to diagnose history of H. pylori infection. The aim was to evaluate the carcinogenic effect of H. pylori.

Methods

A case–control study consisting of 275 gastric cancer patients and 275 age‐ and sex‐matched controls was performed. Serum H. pylori antibody was measured using the “JHM‐Cap” kit with a domestic antigen (cut value of the manufacturer's recommendation was 2.3 EV: ELISA value). Using a conditional logistic model, the odds ratios (ORs) for five cutoff values adjusted for smoking and drinking doses were calculated.

Results

For cutoff values of 1.25, 1.5, 1.75, 2.0, and 2.3 EV, the ORs (95% confidence intervals) were 67.7 (9.1, 502), 37.2 (8.8, 157), 21.3 (9.0, 60.2), 25.5 (9.0, 72.7), and 25.9 (9.2, 73.2), respectively.

Conclusions

These results suggest that the risk ratio of gastric cancer between subjects with and without history of H. pylori infection in Japan may exceed 20.

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.

Immunohistochemical differences in gastric mucosal damage between nodular and non-nodular gastritis caused by Helicobacter pylori infection

In this study, the level of cell damage were analyzed immuno­histochemically to clarify the association between nodular gastritis and undifferentiated gastric cancer. Thirty patients of nodular gastritis were enrolled as the nodular gastritis group. Thirty patients of non-nodular gastritis were enrolled as the control group. They were evaluated according to the updated Sydney system and used for immunohistochemical staining (p53, Ki-67, E-cadherin, and 8-OHdG). The scores based on the updated Sydney system were significantly higher in the nodular group than in the non-nodular group for histologically assessed inflammation and activity in the gastric corpus (1.91 ± 0.77 vs 1.58 ± 0.60, p = 0.049, 0.83 ± 0.81 vs 0.44 ± 0.64, p = 0.032). On immunostaining, the detection of E-cadherin was lower in the nodular group for both the antrum (1.0 ± 0.62 vs 1.47 ± 0.85, p = 0.047) and the corpus (1.16 ± 0.81 vs 1.48 ± 0.71, p = 0.043) and the p53 labeling index of the gastric corpus was higher in the nodular group than in the non-nodular group (3.06 ± 1.94 vs 2.03 ± 1.99, p = 0.015). Nodular gastritis showed significant severe inflammation and immunohistochemical cell damage compared with non-nodular gastritis. These findings may play an important role in the oncogenesis of undifferentiated gastric cancer in nodular gastritis.

Guidelines for the management of Helicobacter pylori infection in Japan: 2016 Revised Edition

BACKGROUND

Since "Helicobacter pylori (H. pylori) infection" was set as the indication in the Japanese Society for Helicobacter Research (JSHR) Guidelines 2009, eradication treatment for H. pylori gastritis is covered under insurance since 2013 in Japan, and the number of H. pylori eradication has rapidly increased. Under such circumstances, JSHR has made the third revision to the "Guidelines for diagnosis and treatment of H. pylori infection" for the first time in 7 years.

METHODS

The Guideline Committee held 10 meetings. Articles published between the establishment of the 2009 Guidelines and March 2016 were reviewed and classified according to the evidence level; the statements were revised on the basis of this review. After inviting public comments, the revised statements were finalized using the Delphi method.

RESULTS

There was no change in the basic policy that H. pylori infectious disease is an indication for eradication. Other diseases presumed to be associated with H. pylori infection were added as indications. Serum pepsinogen level, endoscopic examination, and X-ray examination were added to the diagnostic methods. The effects of 1-week triple therapy consisting of potassium-competitive acid blocker (P-CAB), amoxicillin, and clarithromycin have improved, and high eradication rates can also be expected with proton pump inhibitors (PPI) or P-CAB combined with amoxicillin and metronidazole. If the susceptibility test is not performed, the triple PPI or P-CAB/amoxicillin/metronidazole therapy should be chosen, because the PPI/amoxicillin/metronidazole combination demonstrated a significantly higher eradication rate than PPI/amoxicillin/clarithromycin. In the proposal for gastric cancer prevention, we divided gastric cancer prevention measures by age from adolescent to elderly, who are at an increased gastric cancer risk, and presented measures for gastric cancer prevention primarily based on H. pylori eradication.

CONCLUSION

We expect the revised guidelines to facilitate appropriate interventions for patients with H. pylori infection and accomplish its eradication and prevention of gastric cancer.

A Helicobacter pylori screening and treatment program to eliminate gastric cancer among junior high school students in Saga Prefecture: a preliminary report

BACKGROUND

To present the strategies and preliminary findings of the first 3 years after implementing a Helicobacter pylori screening and eradication program to prevent gastric cancer in Saga Prefecture.

METHODS

A screening and treatment program to eradicate H. pylori from third-grade junior high students was started in Saga Prefecture in 2016, using local governmental grants. Screening was with urinary anti-H. pylori antibody tests, followed by H. pylori stool antigen tests for students who were antibody positive. Those positive on both tests underwent H. pylori eradication by triple therapy based on a potassium-competitive acid blocker.

RESULTS

From 2016 to 2018, the participation rate was 83.1% and the H. pylori infection rate was 3.1% (660/21,042). The participation rates were higher in 2017 (85.4%) and 2018 (85.9%) compared with 2016 (78.5%) (P < 0.0001), and the infection rate also decreased in a time-dependent manner (2016: 3.6%, 2017: 3.3%, 2018: 2.5%, P = 0.0001). In total, 501 students positive for H. pylori received eradication therapy (85.1% success) and adverse events occurred in 20 of these (4.0%). However, no serious complications occurred.

CONCLUSIONS

The H. pylori screening and eradication project for school students in Saga Prefecture has started successfully and we have seen both a steady increase in the participation rate and a steady decrease in the infection rate, without major safety concerns.

Upregulation of the APE1 and H2AX genes and miRNAs involved in DNA damage response and repair in gastric cancer

Gastric cancer remains one of the leading causes of cancer-related death worldwide, and most of the cases are associated with Helicobacter pylori infection. This bacterium promotes the production of reactive oxygen species (ROS), which cause DNA damage in gastric epithelial cells. In this study, we evaluated the expression of important genes involved in the recognition of DNA damage (ATM, ATR, and H2AX) and ROS-induced damage repair (APE1) and the expression of some miRNAs (miR-15a, miR-21, miR-24, miR-421 and miR-605) that target genes involved in the DNA damage response (DDR) in 31 fresh tissues of gastric cancer. Cytoscape v3.1.1 was used to construct the postulated miRNA:mRNA interaction network. Analysis performed by real-time quantitative PCR exhibited significantly increased levels of the APE1 (RQ = 2.55, p < 0.0001) and H2AX (RQ = 2.88, p = 0.0002) genes beyond the miR-421 and miR-605 in the gastric cancer samples. In addition, significantly elevated levels of miR-21, miR-24 and miR-421 were observed in diffuse-type gastric cancer. Correlation analysis reinforced some of the gene:gene (ATM/ATR/H2AX) and miRNA:mRNA relationships obtained also with the interaction network. Thus, our findings show that tumor cells from gastric cancer presents deregulation of genes and miRNAs that participate in the recognition and repair of DNA damage, which could confer an advantage to cell survival and proliferation in the tumor microenvironment.

Serum Pepsinogen Values in Japanese Junior High School Students With Reference to Helicobacter Pylori Infection

Background

Distributions of serum pepsinogen (PG) values were assessed in Helicobacter pylori-infected and non-infected junior high school students (aged 12–15 years) in Japan.

Methods

All junior high school students (1,225 in total) in Sasayama city, who were basically healthy, were asked to provide urine and serum samples, which were used to measure urine and serum H. pylori antibodies using ELISA kits and PG values. The subjects, whose urine and serum antibodies were both positive, were considered H. pylori infected.

Results

Of the 187 subjects who provided urine and blood samples, 8 were infected, 4 had discrepant results, 4 had negative serum antibody titers no less than 3.0 U/ml, and 171 were non-infected. In the H. pylori non-infected subjects, the median PG I and PG II values and PG I to PG II ratio (PG I/II) were 40.8 ng/mL, 9.5 ng/mL, and 4.4, respectively, whereas in the infected subjects, these values were 55.4 ng/mL, 17.0 ng/mL, and 3.3, respectively (each P < 0.01). In the non-infected subjects, PG I and PG II were significantly higher in males than in females (P < 0.01).

Conclusions

The PG I and PG II values were higher, and the PG I/II was lower in H. pylori infected students than in non-infected students. In H. pylori non-infected students, males showed higher PG I and PG II values than females. The distributions of PG values in junior high school students differed from those in adults.

Optimal Criteria and Diagnostic Ability of Serum Pepsinogen Values for Helicobacter pylori Infection

Background

Practical criteria for the use of serum pepsinogen (PG) values in diagnosing Helicobacter pylori infection have not yet been determined.

Methods

The results of gastric endoscopies, H. pylori infection tests, and PG values were retrospectively reviewed. Subjects were assigned to groups, including never-infected (with neither infection nor gastric mucosal atrophy), infected (with atrophy or findings indicating infection in endoscopy and positive infection tests except for antibody tests), and ex-infected (with gastric mucosal atrophy and negative infection tests, except for antibody tests). The optimal criteria with combined use of the PG II concentrations and the PG I/PG II ratio were investigated separately for PG measurements obtained with the chemiluminescent magnetic particle immunoassay (CLIA) and latex agglutination (LA) methods, such that the specificity was greater than 70% and the sensitivity was no less than 95% among the never-infected and infected subjects. Similar analyses were performed by combining the data from ex-infected and infected subjects.

Results

For the CLIA (LA) method, the optimal criterion among 349 (397) never-infected and 748 (863) infected subjects was a PG II value of at least 10 (12) ng/mL or a PG I/PG II ratio no more than 5.0 (4.0), which produced 96.3% (95.1%) sensitivity and 82.8% (72.8%) specificity. When 172 (236) ex-infected subjects were included, the optimal criterion was the same, and the sensitivity was 89.1% (86.9%).

Conclusions

The above criteria may be practical for clinical use, and PG tests using these criteria might prevent unnecessary endoscopic examinations for never-infected subjects.

The administrative project of Helicobacter pylori infection screening among junior high school students in an area of Japan with a high incidence of gastric cancer

OBJECTIVE

Helicobacter pylori infection is a common chronic infection that is closely associated with gastric cancer, known to be decreasing worldwide. We set up an administrative project of screening examination for H. pylori infection in junior high school students in Akita Prefecture to investigate the current prevalence of H. pylori infection in childhood in an area where the incidence of gastric cancer is particularly high.

SUBJECTS AND METHODS

All students in their second or third year of junior high school (13 to 15 years old) in two cities in Akita Prefecture were recruited. First, a urine-based enzyme-linked immunosorbent assay for detection of H. pylori antibody was performed. Then, a ¹³C-urea breath test (¹³C-UBT) was carried out in students who tested positive on the urinary test. Written informed consent was obtained from all participants and their parents.

RESULTS

A total of 1813 students were recruited in this study; 1765 (97.3%) students agreed to participate in this project and underwent a screening examination. Among 96 students (5.4%) testing positive for H. pylori on the initial screening examination, 90 (93.7%, 90/96) underwent a subsequent ¹³C-UBT, and 85 (4.8%, 85/1765) were diagnosed as positive for H. pylori.

CONCLUSIONS

The current prevalence of H. pylori infection among students was low even in an area of Japan with a high incidence of gastric cancer.

Low prevalence and incidence of Helicobacter pylori infection in children: a population-based study in Japan

BACKGROUND

Infection of Helicobacter pylori mainly occurs in childhood. In Japan, incidence of gastric cancer is still high in the senior citizen population, but little is known about the current H. pylori infection status among children or their family members.

METHODS

As a population-based study, the prevalence of H. pylori infection and change in infection status over a 1-year interval in children were determined. Family members of some participants were also invited to participate in the study to determine their infection status. All children of specific ages attending 16 schools in Sasayama, Hyogo Prefecture, were invited to participate. H. pylori infection was determined by the stool antigen test and diagnosis confirmed by polymerase chain reaction and the urea breath test.

RESULTS

Helicobacter pylori prevalence was 1.9% among 689 children aged 0-8 years in 2010 and 1.8% among 835 children aged 0-11 in 2011. No feco-conversion was observed in 430 children aged 0-8 years (170 were aged 0-4 years) who provided follow-up stool samples after 1 year. The prevalence of infection was 6% (2 of 33) and 38% (6 of 16) in mothers of negative and positive probands (p = .04), respectively, and 12% (3 of 25) and 50% (8 of 16) (p = .01), respectively, in fathers.

CONCLUSION

Helicobacter pylori prevalence in Japanese children is approximately 1.8%, which is much lower than that reported in Japanese adults. New infection may be rare. Parent-to-child infection is thought to be the main infection route of the infrequent infection for children in Japan.

Comparative epidemiology of gastric cancer between Japan and China

AIM

To clarify the similarities and differences in gastric cancer epidemiology between Japan and China.

METHODS

A comprehensive literature search of the PubMed database was performed. The relevant literature published in China was also been cited. Data on incidence and mortality rates in 2008 were obtained from the Cancer Mondial database, published by International Agency for Research on Cancer at http://www-dep.iarc.fr/.

RESULTS

Gastric cancer remains a significant public health burden in both Japan and China. The prevalence of Helicobacter pylori (H. pylori) colonization is high in the adult populations of both countries. Accumulating evidence from intervention studies in both countries has shown the effectiveness of H. pylori eradication in reducing gastric cancer incidence. There are differences, however, in many aspects of gastric cancer, including patterns of incidence and mortality, trends in the prevalence of H. pylori infection, H. pylori strains, the magnitude of risk of gastric cancer related to H. pylori infection, and associations with dietary habits. Compared with China, Japan has seen a more rapid decline in H. pylori infection among adolescents. While Japanese cohort studies have dominated the literature concerning the associations between gastric cancer and dietary habits, numerous case-control studies in China suggest a positive association between a high intake of preserved fish and vegetables and gastric cancer risk. There is a need for a multidisciplinary research approach to understand the interactions between various strains of H. pylori, host factors, and other lifestyle and environmental factors in gastric carcinogenesis in both countries.

CONCLUSION

The shared high incidence of gastric cancer and high prevalence of H. pylori, as well as differences in many aspects of gastric cancer, provide an excellent opportunity to establish Sino-Japanese collaborations.

Reduced serum vascular endothelial growth factor receptor-2 (sVEGFR-2) and sVEGFR-1 levels in gastric cancer patients

The relationship between gastric cancer and serum vascular endothelial growth factor receptor-1 (sVEGFR-1) and sVEGFR-2, which are soluble form receptor proteins of vascular endothelial growth factor (VEGF), has not been extensively studied. VEGF, sVEGFR-1 and sVEGFR-2 were measured in the sera obtained before surgical operation from 164 gastric cancer patients and from 164 healthy controls matched for age and gender. Compared with controls, the cases showed elevated VEGF (P < 0.01) and reduced sVEGFR-1 (P = 0.07) and sVEGFR-2 (P = 0.02). The difference in VEGF levels was small among men and when the outcome was early cancer. The difference in sVEGFR-1 levels was significant or borderline significant only in men and when the outcome was diffuse type cancer. The difference in sVEGFR-2 levels was significant only in men and when the outcome was advanced or diffuse type cancer. The sensitivities and specificities of VEGF, sVEGFR-1 and sVEGFR-2 were all approximately 60%. For diffuse type cancer, sVEGFR-2 showed a sensitivity of 62.4% and a specificity of 63.4%, which was similar to serum pepsinogen. In conclusion, elevated VEGF and reduced sVEGFR-1 and sVEGFR-2 in serum are characteristic of gastric cancer patients, and the value of serum sVEGFR-2 in the diagnosis of diffuse type gastric cancer should be further evaluated.

Safety and efficacy of long-term maintenance therapy with oral dose of rabeprazole 10 mg once daily in Japanese patients with reflux esophagitis

OBJECTIVE

The aim of this prospective clinical study was to evaluate the efficacy and safety of long-term proton pump inhibitor (PPI) treatment for two years in Japanese patients with reflux esophagitis (RE).

METHODS

The efficacy and safety of two-year (104-week) treatment with rabeprazole (RPZ) 10 mg were studied in patients confirmed to have been cured of RE by PPI and who required long-term maintenance therapy with PPI. We performed serial endoscopy, checked gastroesophageal reflux disease (GERD) symptoms, adverse events, laboratory values and serum gastrin. We also monitored gastric mucosal histology, atrophy and polyps.

RESULTS

The endoscopic non-relapse rate for RE was 87.3% for the 104-week period. GERD symptoms improved based on the fact that the mean change from baseline in GERD symptom score after treatment was a negative value. Treatment was safe; and atrophy was found to have developed in virtually no cases. A few new benign fundic gland or hyperplastic polyps developed throughout the study, but no ECL carcinoids were found to have developed. Serum gastrin levels tended to increase up to 24 weeks, but there were no subsequent changes thereafter up to 104 weeks.

CONCLUSION

The results confirmed oral RPZ 10 mg to be effective for maintenance therapy in Japanese patients with RE. Although effects on the gastric mucosa were not ruled out, long-term use of RPZ was confirmed to be safe overall.

Host and environmental factors for gastric cancer in Babol, the Caspian Sea Coast, Iran

To clarify host and environmental factors for gastric carcinogenesis, we obtained information about gastric cancer mortality in Babol, in the North of Iran, and recruited 130 participants aged 30-80 years from the general population of Babol in 2004. A urea breath test, assessment of IgG antibodies to Helicobacter pylori, a pepsinogen test, a marker of chronic atrophic gastritis, and determination of urinary excretions of sodium and potassium were performed. Diet and lifestyle information was also obtained using a questionnaire. The stomach cancer mortality rate for men in Babol (38.2/10(5)) was found to be somewhat lower than that for Japanese men (45.1/10(5)), while the mortality for women (26.9/10(5)) was higher than for Japanese women (20.9/10(5)). Positive rates for the urea breath test were 77.5 and 81.8% for Iranian men and women, respectively. Helicobacter pylori IgG antibodies were present in 68.7 and 73.7% of Iranian men and women, respectively, both values being marginally higher than for Japanese. We also found 51.0 and 52.8% to be positive for a pepsinogen test, significantly higher than the Japanese values. Urinary excretions of salt and potassium in this population appeared approximately the same as the consumption in Japanese. The elevated gastric cancer mortality in both men and women in Babol seems, by and large, to be related to higher H. pylori infection rates and prevalence of chronic atrophic gastritis. Certain factors, including H. pylori DNA diversity, host factors and their interactions, together with the level of medical practice, prevalence of and access to secondary prevention of stomach cancer, may also be associated with the relatively high mortality.

The decreasing burden of gastric cancer in Japan

Gastric cancer in Japan, previously the top killer cancer, has recently shown decreased incidence and mortality rates. Epidemiological studies have demonstrated that environmental factors are closely associated with stomach oncogenesis, as evident from the geographical differences seen throughout Japan in both incidence and mortality. Moreover, Japanese immigrant populations gradually exhibit the lower incidence and mortality rates of gastric cancer in their chosen country. Likewise, younger generations in Japan have lower mortality rates than older generations at the same age, which may be accounted by the dramatic lifestyle changes in Japan after World War II. In addition to exploring and learning from the impact of these environmental factors, deliberate strategies to further lower the incidence and mortality rates of gastric cancer must include aggressive eradication programs for Helicobacter pylori and dietary education in both school curricula and for the general adult population to lower the intake of causative agents such as salt and increase the intake of beneficial agents such as fruits, vegetables and seaweeds. The dietary education should be coupled with better motivation for the general population to undergo regular screening with improved techniques. In the future, changes in these environmental factors and progresses in the diagnosis of and therapeutic strategies for gastric cancer will lead to further decrease in the incidence and mortality rates of this disease in Japan.

Helicobacter pylori, chronic atrophic gastritis, inactive aldehyde dehydrogenase-2, macrocytosis and multiple upper aerodigestive tract cancers and the risk for gastric cancer in alcoholic Japanese men

BACKGROUND

Gastric carcinoma occurs at a high rate in alcoholic Japanese men. Inactive heterozygous aldehyde dehydrogenase-2 (ALDH2*1/2*2) and macrocytosis (mean corpuscular volume [MCV] > or = 106 fl) enhance the risk for esophageal carcinoma, which frequently occurs with gastric carcinoma in this population. Whether alcoholism affects Helicobacter pylori-induced chronic atrophic gastritis (CAG) is unknown.

METHODS

This study of Japanese alcoholic men with (n = 45) and without (n = 281) gastric carcinoma included assessment of H. pylori IgG antibody, serum pepsinogen-confirmed CAG, MCV, and ALDH2 genotype.

RESULTS

The gastric carcinoma cases had a significantly higher age-adjusted prevalence of H. pylori-positivity (78%vs 57%), CAG (78%vs 42%), ALDH2*1/2*2 (36%vs 14%), MCV > or =106 fl (38%vs 20%), and concurrent esophageal/oropharyngolaryngeal carcinoma (18%vs 5%) than controls. Among gastric cancer-free controls, the prevalence of CAG was higher than generally reported in Japan, regardless of H. pylori status (H. pylori-positive, 56%vs 35-36% for Japanese general population; H. pylori-negative, 8%vs 1-3%). Alcoholism may accelerate the progression of CAG. Each of these factors increased the risk of gastric carcinoma (OR(s) = 3.7 for H. pylori-positive, 2.7 for non-severe CAG, 8.7 for severe CAG, 3.5 for ALDH2*1/2*2, 2.5 for MCV > or =106 fl, and 3.7 for concurrent carcinoma). A multivariate analysis showed that CAG and ALDH2*1/2*2 were independently related to the risk of gastric carcinoma. Combinations of CAG and ALDH2*1/2*2 showed greater risks of gastric carcinoma (OR(s) = 4.0 for non-severe CAG alone, 17.6 for severe CAG alone, 9.7 for ALDH2*1/2*2 alone, 17.1 for non-severe CAG plus ALDH2*1/2*2, and 39.2 for severe CAG plus ALDH2*1/2*2).

CONCLUSIONS

Combining blood tests for H. pylori, CAG, MCV and ALDH2 genotype could offer a new means of predicting risk of gastric carcinoma in Japanese alcoholic men.

Highly salted food and mountain herbs elevate the risk for stomach cancer death in a rural area of Japan

BACKGROUND

Although many case-control and experimental studies have shown that highly salted foods are risk factors for stomach cancer, only a few cohort studies have supported the relationship.

METHODS

In a cohort study conducted in a rural area of Japan, 8035 residents aged over 30 years (approx. 55% were female) filled out a questionnaire. Seventy-six of them died from stomach cancer during an 11-year follow-up period. In the questionnaire, intake frequencies of 29 food items, smoking and drinking habits were investigated. Tsukemono (pickled vegetables) and tsukudani (foods deep boiled in soy sauce) are highly salted foods in the area. Frequency of each food item intake was classified into three levels, and age- and sex-adjusted risks were calculated using proportional hazard models.

RESULTS

In the final model obtained by backward elimination, frequent intake of tsukemono and tsukudani and that of mountain herbs remained as significant risk factors. Compared with the least frequent intake, risk (95% confidence interval) of the most frequent intake was 5.4 (1.8-16.3) for highly salted foods (P for trend < 0.01) and 3.7 (1.4-9.6) for mountain herbs (P for trend = 0.04).

CONCLUSION

Highly salted foods and mountain herbs were important risk factors for death from stomach cancer.

Helicobacter pylori infection appears essential for stomach carcinogenesis: observations in Semarang, Indonesia

The gastric cancer incidence in Semarang, Indonesia, is exceedingly low: only approximately 1/100th of the level in Japan. To elucidate the reason, we carried out an ecological study recruiting 69 male and 102 female participants from the general populace in January 2005. Positive urea breath tests were 0% for both men and women, and Helicobacter pylori (H. pylori) IgG antibodies were found in 2% (0-5, 95% confidence interval) of men and 2% (0-4) of women, significantly lower than the 62% (58-65) and 57% (53-60), respectively, in Japan. Furthermore, there were no positive findings with the pepsinogen tests in Semarang, again significant in comparison with the 23% (22-25) and 22% (20-23) in Japan. Variation in smoking levels and consumption of NaCl, vegetables and fruit were found, but not to an extent that would allow explanation of the major differences in gastric cancer incidence. We may conclude that the very low prevalence of H. pylori infection and thus chronic atrophic gastritis account for the rarity of stomach cancer in Semarang, Indonesia.

Serum pepsinogen values and Helicobacter pylori status among control subjects of a nested case-control study in the JACC study

BACKGROUD: Helicobacter pylori infection and serum pepsinogen values are strongly related with stomach cancer. The aim of this study was to know what were these factors among general population.

METHODS: Subjects were randomly selected 633 control subjects in a nested case-control study for risk of stomach cancer. Most of them were from rural areas of Japan. Using frozen sera, pepsinogen I (PG I) and II (PG II) values and H. pylori antibody were measured. Those with PG I less than 50 ng/mL and the ratio of PG I to PG II (PG I/II) was less than 2.0 were defined as severe, those with PG I less than 70 ng/ml and PG I/II less than 3.0 were defined as mild and the other subjects were defined as no serological atrophy.

RESULTS: About 70% of the subjects were H. pylori seropositive and the seroprevalence did no depend on age or sex. Percentages of those with severe serological atrophy increased with age from 10% in those aged 40-49 years to 38% in 70 and more, and percentages of those with mild serological atrophy were about 30% independent of age.

CONCLUSIONS: The subjects, who were expected to represent populations of rural area of Japan, had high prevalence of both H. pylori infection and serological atrophy of gastric mucosa. These facts should be considered in discussing results of the nested case-control study.

Epidemiology of gastric cancer in Japan

Despite its decreasing trend in Japan, gastric cancer remains an important public health problem. Although the age standardised rates of gastric cancer have been declining for decades, the absolute numbers are increasing because of the rapid aging of the population. A large proportion of Japanese gastric cancers are detected at an early stage, with a better overall survival rate. As with Western developed countries, a change in the social environment such as reduced salt use and increased fresh vegetable and fruit intake as well as improvement of food storage may play an important part in the decline. Differences in Helicobacter pylori infection rates between generations presumably have contributed to the generation related variation in the declining trends. It is expected that most gastric cancers in Japan may be preventable by lifestyle modification such as salt reduction and increased fruit and vegetable intake, together with avoidance of smoking and countermeasures against H pylori infection so that the level now evident in Western developed countries can be reached.

Rare Helicobacter pylori infection as a factor for the very low stomach cancer incidence in Yogyakarta, Indonesia

To elucidate factors associated with the very low risk of gastric neoplasia in Yogyakarta, Indonesia, approximately 1/50 of the level in Japan, we recruited 52 male and 39 female participants from the general populace in the city of Yogyakarta in October 2003. Helicobacter pylori IgG antibodies were found in only 5% (0-13) (95% confidence interval) and 4% (0-9) for Javanese males and females, respectively, and were statistically lower than the 62% (58-65) and 57% (53-60), respectively, in Japanese. Furthermore, positive findings of pepsinogen test were only 0 and 2% (0-6) for males and females, in Yogyakarta, and were again significantly lower than the 23% (22-25) and 22% (20-23), in Japan. The very low incidence of stomach cancer in Yogyakarta may be due to a low prevalence of H. pylori infection and chronic atrophic gastritis.

Seroconversion and seroreversion of Helicobacter pylori antibodies over a 9-year period and related factors in Japanese adults

BACKGROUND

There are still insufficient data on the frequency of seroconversion and seroreversion of Helicobacter pylori antibodies. The frequency of serochange and related factors were investigated in this study over 9 years.

SUBJECTS AND METHODS

Using sera from 3104 workers who underwent health checks in 1989 and again in 1998, H. pylori antibodies were measured. Those with intermediate serology were excluded from the study. Information on past history was collected using a questionnaire.

RESULTS

Of the 912 seronegative and 1286 seropositive subjects in 1989, seroconversion was observed in 57 and seroreversion in 91 subjects. Seroconversion and seroreversion rates over the 9-year period were 6.3% and 7.1%, respectively, giving rates per 1000 person-years (with 95% confidence interval) of 7.0 (5.2-8.7) and 7.9 (6.3-9.4), respectively. Subjects that reported abdominal symptoms or gastric fiberscope use showed significantly higher seroconversion rates than controls (8.7 vs. 4.5 and 9.2 vs. 1.6, respectively), which remained significant after adjustment for age and gender. Those with a history of duodenal ulcers, a smoking habit or a drinking habit showed significantly lower seroreversion rates than controls (3.5 vs. 8.9, 5.4 vs. 9.2 and 5.9 vs. 13.3, respectively). After adjustment, the association between seroreversion and smoking habit disappeared, while the associations with history of duodenal ulcers and drinking habit remained.

CONCLUSIONS

Those with a history of nonspecific abdominal symptoms and those with a history of gastric fiberscope use showed higher seroconversion rates. Alcohol consumption and duodenal ulcers may inhibit the autoeradication of H. pylori, possibly through increased acid secretion.

Platelet recovery in patients with idiopathic thrombocytopenic purpura after eradication of Helicobacter pylori

The relationship between Helicobacter pylori infection and idiopathic thrombocytopenic purpura (ITP) has been investigated in several studies. We investigated the prevalence of H. pylori infection and the clinical effects of eradication in 22 Japanese patients with chronic ITP. H. pylori infection was found in 14 (63.6%) of the patients by histologic and culture examinations of biopsy samples obtained by gastrointestinal endoscopy. H. pylori was eradicated by proton pump inhibitors and 2 kinds of antibiotics in 13 (92.9%) of the 14 patients in whom the results of treatment could be evaluated. Five (38.4%) of those 13 patients had platelet recovery (platelet count of more than 100 x 10(9)/L and an increase of more than 30 x 10(9)/L with respect to the baseline value) after eradication. The median follow-up period was 15 months. One patient who had a complete response had a partial relapse after cessation of prednisolone treatment without any evidence of H. pylori reinfection. Another patient, in whom H. pylori was not eradicated even after 2 treatment sessions, had a partial response after treatment. A screening examination for H. pylori infection may be necessary for Japanese patients with newly diagnosed ITP. Although the exact mechanism underlying platelet recovery after H. pylori eradication is not clear, the results of this study indicated that H. pylori eradication treatment is a good option for some patients with chronic ITP.

Serum copper/zinc superoxide dismutase (Cu/Zn SOD) and gastric cancer risk: a case-control study

We conducted a case-control study to evaluate the association between serum levels of copper/zinc superoxide dismutase (Cu/Zn SOD) and the risk of gastric cancer. Cases were 214 patients who had been diagnosed with gastric cancer and controls were 120 persons who underwent medical checkups. Serum levels of Cu/Zn SOD were determined by enzyme-linked immunosorbent assay (ELISA). Compared with the lowest quartile, the OR (odds ratio) was 4.54 (95% CI (confidence interval), 1.62 - 12.66) for the third quartile and 15.75 (95% CI, 5.84 - 42.46) for the highest quartile. With both early and advanced cancers, as well as with the intestinal and diffuse types, a significant increase in risk was observed with increasing levels of serum Cu/Zn SOD. Our case-control study showed that serum levels of Cu/Zn SOD were significantly elevated in gastric cancer patients compared with apparently healthy controls, and higher Cu/Zn SOD levels may be associated with an increased risk of gastric cancer.

U-shaped effect of drinking and linear effect of smoking on risk for stomach cancer in Japan

A case-control study was conducted to evaluate the relationship between smoking or drinking doses and risk for stomach cancer, and to clarify whether the relationship is dose-dependent or U-shaped. Smoking dose was categorized as 0, 1 - 399, 400 - 799, or 800 + cigarette-years, and drinking dose as 0, occasional/0.1 - 134.9, 135 - 1349.9, or 1350 + alcohol-years (ml of pure alcohol intake per day multiplied by years of drinking). Helicobacter pylori status was determined by serology for adjustment. Using logistic regression, the adjusted effects of smoking and drinking doses on risk for stomach cancer were calculated for both genders. Among male subjects, the odds ratios (95% confidence intervals (CIs)) were 1.29 (0.76, 2.18) for 1 - 399, 1.71 (1.05, 2.80) for 400 - 799 and 2.46 (1.49, 4.07) for 800 + cigarette-years compared with never-smokers, and 1.89 (0.97, 3.69) for never-drinkers, 2.82 (1.63, 4.86) for 135 - 1349.9 and 2.84 (1.97, 4.83) for 1350.0 +, compared with occasional/0.1 - 134.9 alcohol-years. Among female subjects, they were 0.44 (0.20, 1.00) for 1 - 399 and 2.471 (0.91, 6.68) for 400 + cigarette-years compared with never-smokers, and 1.54 (0.90, 2.63) for never-drinkers and 1.39 (0.66, 2.93) for 135.0 + alcohol-years. Smoking seems to exert a linear effect and drinking, a J- or U-shaped effect on risk for stomach cancer, although there might be a dip of risk in light smokers among female subjects.