Racial differences in Helicobacter pylori, serum pepsinogen and gastric cancer incidence in an urban Asian population

Serum pepsinogen level as a biomarker for atrophy, reflux esophagitis, and gastric cancer screening in Indonesia

Background

Chronic dyspepsia's symptoms are frequently seen in primary to tertiary healthcare in Indonesia. This study aimed to describe the potential usability of pepsinogen (PG) values in determining gastric mucosal conditions, including superficial gastritis and atrophic gastritis.

Materials and Methods

We recruited 646 adult dyspeptic patients and then analyzed PG values (including PGI, PGII, and PGI/II ratio) with endoscopic findings, gastric mucosal damages, and Helicobacter pylori infection. The gastric mucosal damage and H. pylori infection were evaluated using histological examination based on the updated Sydney system.

Results

Among 646 enrolled patients, 308 (47.2%), 212 (32.8%), 91 (14.1%), 34 (5.2%), and 1 (0.2%) patient were diagnosed with normal mucosa, gastritis, reflux esophagitis, peptic ulcer disease, and gastric cancer, respectively. Significant differences in PGI, PGII, and PGI/II ratio values were observed among ethnic groups (all P < 0.01). The PGI and PGII levels were significantly higher and PGI/II was significantly lower in H. pylori-infected patients than in uninfected ones (all P < 0.001). The optimal cutoff value for PGII and PGI/II was 12.45 ng/mL with an area under the curve (AUC) value of 0.755 (0.702-0.811), sensitivity 59.3%, and specificity 77.1%; and 4.75 with AUC value of 0.821 (0.763-0.855), sensitivity 81.5%, and specificity 78.7%, respectively, to determine moderate-severe atrophy.

Conclusion

Serum PG levels, a useful biomarker, represent the endoscopic findings, especially for reflux esophagitis. In addition, the benefits of PG values detecting atrophic gastritis were limited to moderate-severe atrophic gastritis. This usefulness requires careful attention for several ethnic groups in Indonesia.

Effect of aqueous extract of seed of broccoli on inflammatory cytokines and Helicobacter pylori infection: a randomized, double-blind, controlled trial in patients without atrophic gastritis

The purpose of this study was to investigate the anti-inflammatory effect of an aqueous extract of seed of broccoli (AESB) in Helicobacter pylori (HP)-infected patients without atrophic gastritis. This was a double-centre, randomized, double-blind, controlled study. A total of 110 HP-infected subjects were randomized to receive either AESB or placebo for 2 months. Inflammatory cytokine (IL-8, IFN-γ, TNF-α, CRP, IL-17A, IL-1β, IL-18), pepsinogen I, II (PG I, PG II), and gastrin-17 (G-17) measurements and ¹³C-urea breath tests were performed at baseline and at 60 days. At 60 days, there was no significant difference in any of the inflammatory cytokines, pepsinogen or gastrin between the two groups. However, IL-8, IFN-γ, PG I, PG I/PG II ratio (PGR), and G-17 were reduced by 9.02 pg/mL, 5.08 pg/mL, 24.56 ng/mL, 1.75 and 0.3 pmol/L, respectively, in the AESB group compared with baseline (all P < 0.05). The HP eradication rates in the AESB group and placebo group were 11.11 and 3.70% at 60 days, respectively (P > 0.05). No treatment-related adverse events were reported. Thus, AESB may reduce the risk of gastric mucosal lesions and decrease the risk of gastric cancer by relieving inflammatory cytokines. The safety profile of AESB was satisfactory. This study is registered with the Chinese Clinical Trials Registry (Registration No. ChiCTR2100054249).

Severity of gastric intestinal metaplasia predicts the risk of gastric cancer: a prospective multicentre cohort study (GCEP)

OBJECTIVE

To investigate the incidence of gastric cancer (GC) attributed to gastric intestinal metaplasia (IM), and validate the Operative Link on Gastric Intestinal Metaplasia (OLGIM) for targeted endoscopic surveillance in regions with low-intermediate incidence of GC.

METHODS

A prospective, longitudinal and multicentre study was carried out in Singapore. The study participants comprised 2980 patients undergoing screening gastroscopy with standardised gastric mucosal sampling, from January 2004 and December 2010, with scheduled surveillance endoscopies at year 3 and 5. Participants were also matched against the National Registry of Diseases Office for missed diagnoses of early gastric neoplasia (EGN).

RESULTS

There were 21 participants diagnosed with EGN. IM was a significant risk factor for EGN (adjusted-HR 5.36; 95% CI 1.51 to 19.0; p<0.01). The age-adjusted EGN incidence rates for patients with and without IM were 133.9 and 12.5 per 100 000 person-years. Participants with OLGIM stages III-IV were at greatest risk (adjusted-HR 20.7; 95% CI 5.04 to 85.6; p<0.01). More than half of the EGNs (n=4/7) attributed to baseline OLGIM III-IV developed within 2 years (range: 12.7-44.8 months). Serum trefoil factor 3 distinguishes (Area Under the Receiver Operating Characteristics 0.749) patients with OLGIM III-IV if they are negative for H. pylori. Participants with OLGIM II were also at significant risk of EGN (adjusted-HR 7.34; 95% CI 1.60 to 33.7; p=0.02). A significant smoking history further increases the risk of EGN among patients with OLGIM stages II-IV.

CONCLUSIONS

We suggest a risk-stratified approach and recommend that high-risk patients (OLGIM III-IV) have endoscopic surveillance in 2 years, intermediate-risk patients (OLGIM II) in 5 years.

Pepsinogen and Serum IgG Detection Is a Valuable Diagnostic Method for Helicobacter pylori Infection in a Low-Prevalence Country: A Report from Sri Lanka

The use of serum anti-Helicobacter pylori IgG and pepsinogen (PG) detection as a diagnostic method was evaluated in Sri Lanka. Gastric biopsies were performed (353 patients), and the prevalence of H. pylori infection was 1.7% (culture) and 2.0% (histology). IgG serology testing showed an area under the curve (AUC) of 0.922 (cut-off, 2.95 U/mL; specificity, 91.56%; sensitivity, 88.89%). Histological evaluation showed mild atrophy (34.3%), moderate atrophy (1.7%), metaplasia (1.7%), chronic gastritis (6.2%), and normal tissue (56%). The PGI/PGII ratio was significantly higher in H. pylori-negative patients (p < 0.01). PGII and PGI/PGII levels were lower in patients with metaplasia than in those with normal mucosa (p = 0.049 and p < 0.001, respectively). The PGI/PGII ratio best discriminated metaplasia and moderate atrophy (AUC 0.88 and 0.76, respectively). PGI and PGII alone showed poor discriminative ability, especially in mild atrophy (0.55 and 0.53, respectively) and chronic gastritis (0.55 and 0.53, respectively). The best cut-off to discriminate metaplasia was 3.25 U/mL (95.19% specificity, 83.33% sensitivity). Anti-H. pylori IgG and PG assessment (ABC method) was performed (group B, 2.0%; group A, 92.1%). The new cut-off more accurately identified patients with metaplasia requiring follow-up (group B, 5.4%). Assessment of anti-H. pylori IgG and PG is valuable in countries with a low prevalence of H. pylori infection.

Helicobacter pylori Treatment Strategies in Singapore

The management of Helicobacter pylori infection in Singapore remains a clinical challenge. Similar to other regions, there has been an increase in antibiotic resistance rates through the years. Nonetheless, over the past two decades, clarithromycin-based triple therapy has continued to be used as the first line treatment option, with an eradication rate exceeding 90%, although the accepted treatment duration must now be lengthened from 1 to 2 weeks to maintain efficacy. Concomitant and sequential therapies did not demonstrate superiority over standard triple therapy. Current empiric second line treatment utilizes either bismuth-based quadruple therapy or levofloxacin-based triple therapy, but outcomes remain less than ideal. Identifying options to further improve treatment success rates is challenging. Strategies being considered include the use of potent acid suppressants, such as vonoprazan, and H. pylori culture and antibiotic susceptibility testing-guided therapy.

Screening for gastric cancer in China: Advances, challenges and visions

Gastric cancer (GC) is one of the major cancers in China and all over the world. Most GCs are diagnosed at an advanced stage with unfavorable prognosis. Along with some other countries, China has developed the government-funded national screening programs for GC and other major cancers. GC screening has been shown to effectively decrease the incidence of and mortality from GC in countries adopting nationwide screening programs (Japan and Korea) and in studies based on selected Chinese populations. The screening of GC relies mostly on gastroendoscopy, the accuracy, reliability and safety of which have been indicated by previous studies. However, considering its invasive screening approach, requirements on skilled endoscopists and pathologists, and a high cost, developing noninvasive methods to amend endoscopic screening would be highly needed. Numerous studies have examined biomarkers for GC screening and the combination of biomarkers involving pepsinogen, gastrin, and Helicobacter pylori antibodies has been proposed for risk stratification, seeking to narrow down the high-risk populations for further endoscopy. Despite all the achievements of endoscopic screening, evidence on appropriate screening age, intervals for repeated screening, novel biomarkers promoting precision prevention, and health economics need to be accumulated to inform policymakers on endoscopic screening in China. With the guide of Health China 2030 Planning Outline, we have golden opportunities to promote prevention and control of GC. In this review, we summarize the characteristics of screening programs in China and other East Asian countries and introduce the past and current approaches and strategies for GC screening, aiming for featuring the latest advances and key challenges, and illustrating future visions of GC screening.

Endoscopy for Gastric Cancer Screening Is Cost Effective for Asian Americans in the United States

BACKGROUND & AIMS

Endoscopic screening for gastric cancer is routine in some countries with high incidence and is associated with reduced gastric cancer-related mortality. Immigrants from countries of high incidence to low incidence of gastric cancer retain their elevated risk, but no screening recommendations have been made for these groups in the United States. We aimed to determine the cost effectiveness of different endoscopic screening strategies for noncardia gastric cancer, compared with no screening, among Chinese, Filipino, Southeast Asian, Vietnamese, Korean, and Japanese Americans.

METHODS

We generated a decision-analytic Markov model to simulate a cohort of asymptomatic 50-year-old Asian Americans. The cost effectiveness of 2 distinct strategies for endoscopic gastric cancer screening was compared with no screening for each group, stratified by sex. Outcome measures were reported in incremental cost-effectiveness ratios (ICERs), with a willingness-to-pay threshold of $100,000/quality-adjusted life-year (QALY). Extensive sensitivity analyses were performed.

RESULTS

Compared with performing no endoscopic gastric cancer screening, performing a 1-time upper endoscopy with biopsies, with continued endoscopic surveillance if gastric intestinal metaplasia was identified, was cost effective, whereas performing ongoing biennial endoscopies, even for patients with normal findings from endoscopy and histopathology, was not. The lowest ICERs were observed for Chinese, Japanese, and Korean Americans (all <$73,748/QALY).

CONCLUSIONS

Endoscopic screening for gastric cancer with ongoing surveillance of gastric preneoplasia is cost effective for Asian Americans ages 50 years or older in the United States. The lowest ICERs were for Chinese, Japanese, and Korean Americans (all <$73,748/QALY).

Serum pepsinogens as a gastric cancer and gastritis biomarker in South and Southeast Asian populations

Serum pepsinogens have been widely acknowledged as gastric mucosal biomarkers; however, a multicountry report on the benefits of pepsinogens as biomarkers has not yet been published. We analyzed 1,206 sera and gastric mucosal samples collected from Bangladesh, Bhutan, Indonesia, Myanmar, Nepal and Thailand then assessed the association between gastric mucosal changes and Helicobacter pylori infection. The new cutoff values for serum pepsinogen values were evaluated using a receiver operating characteristic analysis. The participants with H. pylori infection had significantly lower pepsinogen I and higher pepsinogen II values, but a lower pepsinogen I/II ratio than participants without the infection (all P < .001). The pepsinogen I and pepsinogen I/II values were significantly higher and lower, respectively, in individuals with atrophic gastritis than in those without (both P < .001). Among uninfected individuals, only the pepsinogen I/II ratio was significantly lower in atrophic individuals. Pepsinogen I/II ratio also were significantly different between disease among H. pylori-positive and H. pylori-negative individuals, suggesting the pepsinogen I/II ratio is a robust biomarker for determining both chronic and atrophic gastritis. The cutoffs for detecting chronic and atrophic gastritis for the pepsinogen I/II ratio were 4.65 and 4.95, respectively. In conclusion, pepsinogen levels are useful biomarker for both chronic gastritis and atrophic gastritis, but they should be used with caution. Population-based validation is necessary to determine the best cutoff values. Among all pepsinogen values, the pepsinogen I/II ratio was the most reliable gastric mucosal-change biomarker.

Identifying high-risk individuals for gastric cancer surveillance from western and eastern perspectives: Lessons to learn and possibility to develop an integrated approach for daily practice

Current evidence shows that individuals with gastric dysplasia, severe and extensive gastric atrophy, extensive gastric intestinal metaplasia and the incomplete subtype of intestinal metaplasia are at high risk for gastric cancer (GC) development. There are several approaches to identifying these subjects, including noninvasive methods, esophagogastroduodenoscopy and histology. The main approach in Western countries is histology-based while that in Eastern countries with a high prevalence of GC is endoscopy-based. Regarding asymptomatic individuals, the key issues in selecting applicable approaches are the ability to reduce GC mortality and the cost-effectiveness of the approach. At present, population-based screening programs have only been applied in a few Asian countries with a high risk of GC. Pre-endoscopic risk assessment based on demographic and clinical features, such as ethnicity, age, gender, smoking and Helicobacter pylori status, is helpful for identifying subjects with high pre-test probability for a possibly cost-effective approach, especially in intermediate- and low-risk countries. Regarding symptomatic patients with indications for esophagogastroduodenoscopy, the importance of opportunistic screening should be emphasized. The combination of endoscopic and histological approaches should always be considered as endoscopy provides a real-time assessment of the patient's risk level. In addition, imaging enhanced endoscopy (IEE) has been shown to facilitate targeted biopsies resulting in better correlation between endoscopic and histological findings. Currently, the use of IEE is recommended for endoscopic examinations, and the Operative Link for Gastric Intestinal Metaplasia or Operative Link on Gastritis Assessment grading systems are recommended for histological examinations whenever available. However, resource limitations are an important barrier in many regions worldwide. Thus, for an approach to be applicable in real-life practice, it should be not only evidence-based but also resource-sensitive. In this review, we discuss the current understanding and approaches to identifying high-risk individuals from western and eastern perspectives, as well as the possibility of an integrated, resource-sensitive approach.

Histopathological features of the proper gastric glands in FVB/N-background mice carrying constitutively-active aryl-hydrocarbon receptor

Background

Aryl-hydrocarbon receptor (AhR) is a multiple ligand-activated transcription factor that has important roles in xenobiotic, physiological, or pathological functions. Transgenic mice systemically expressing constitutively-active AhR (CA-AhR) have been created to mimic activated AhR signaling in vivo. However, their detailed histopathological features are unclear. In the present study, we generated CA-AhR-expressing FVB/N mice (FVB-CA-AhR mice) and clarified their phenotypes in detail.

Methods

Male and female FVB-CA-AhR and wild-type mice were histopathologically examined from 6 to 33 weeks of age.

Results

Among the systemic organs, only the stomachs in FVB-CA-AhR mice showed pathological changes including cystic structures beneath the serosa; in addition, stomach weights increased with age. Histopathologically, cystic structures and alcian blue-positive metaplasia were observed in the mucosa of the proper gastric glands, and these two histometric parameters were positively correlated. Furthermore, proliferating cells shifted from the isthmus to the base of the glands, and parietal cells decreased. Age-related histopathological changes were clearer in females than in males. Importantly, in FVB-CA-AhR mice, intramucosal cysts developed as extramucosal cysts beneath the serosa, penetrating the lamina muscularis mucosae and the muscularis propria. Their incidence reached 100% in 28-week-old male mice and 33-week-old female mice. Extramucosal cysts contained alcian blue-, Griffonia simplicifolia lectin II-, or trefoil factor 2-positive cells, suggesting a stomach origin for the cysts and spasmolytic polypeptide-expressing metaplasia-like lesions.

Conclusions

Disease onset occurred earlier in FVB-CA-AhR mice than previously reported in C57BL/6-derived CA-AhR mice. Importantly, the histopathological features were partly similar with gastritis cystica profunda in humans and animals. Excessive activation of AhR signaling aggravated abnormalities in the gastric mucosa and were affected by both genetic- and sex-related factors.

Electronic supplementary material

The online version of this article (10.1186/s12876-019-1009-x) contains supplementary material, which is available to authorized users.

Stage-matched survival differences by ethnicity among gastric cancer patients of Asian ancestry treated in the United States

BACKGROUND

Differences have been noted in overall survival (OS) in gastric cancer (GC) between trials conducted in Western vs Asian countries. The National Cancer Database (NCDB) reports outcomes and patient/disease variables relevant to OS.

METHODS

Using NCDB, we identified 89 558 adult patients with GC diagnosed (2004-2012), where self-reported race/ethnicity was available. Cox proportional hazard model was used to calculate multivariable hazard ratio (HR) of death, adjusting for race/ethnicity, age, gender, insurance, histology, grade, location, stage, and treatment type.

RESULTS

After adjustment, Asian patients had improved OS (HR = 0.74, 95% confidence intervals [CI] = 0.71-0.77). There were differences in OS between Asian ethnicities compared with white patients (n = 69 945), notably with Korean (n = 1249, HR = 0.70, 95% CI = 0.64-0.75), Chinese (n = 1271, HR = 0.69, 95% CI = 0.64-0.75), and Indian/Pakistani patients (n = 492, HR = 0.68, 95% CI = 0.61-0.76). Japanese (n = 829, HR = 0.84, 95% CI = 0.77-0.91) and Vietnamese (n = 560, HR = 0.79, 95% CI = 0.71-0.88) OS was also improved (P < 0.0001), while Filipino patients showed no difference (n = 415, HR = 1.00). Black patients had slightly improved OS (n = 13 500, HR = 0.98, 95% CI = 0.95-1.00, P = 0.035).

CONCLUSIONS

This analysis supports improved OS in Asian patients independent of stage, treatment, and known patient or disease characteristics in this large US cohort, and is the largest to define OS differences between Asian ethnicities.

Clinical application of magnetically controlled capsule gastroscopy in gastric disease diagnosis: recent advances

Magnetically controlled capsule gastroscopy (MCCG) is a novel system primarily used for the diagnosis of gastric disease. It consists of an endoscopic capsule with magnetic material inside, external guidance magnet equipment, data recorder and computer workstation. Several clinical trials have demonstrated that MCCG is comparable in accuracy in diagnosing gastric focal disease when compared to conventional gastroscopy. Further clinical studies are needed to test the diagnostic accuracy and improve the functioning of MCCG. This novel MCCG system could be a promising alternative for screening for gastric diseases, with the advantages of no anesthesia required, comfort and high acceptance across populations.

Long-term outcome of group D patients with negative serum anti-Helicobacter pylori antibody and positive serum pepsinogen test in healthy Koreans

OBJECTIVE

The aim of this study was to assess the clinical characteristics and long-term outcomes of group D patients (negative H. pylori antibodies and positive pepsinogen level).

METHODS

Group D patients were divided into two groups, that is, the limited endoscopic atrophic gastritis (EAG) group with EAG confined to the antrum and angle (C1 and C2) and the advanced EAG group with gastric body-involved EAG (C3 to O3). We compared the progression of precursor lesions and the occurrence of gastric neoplasms between the two groups.

RESULTS

Among 107 group D patients, the advanced EAG group (n = 60) was elder and had a lower pepsinogen I level and a lower pepsinogen I to II ratio (PGI/II) than the limited EAG group (n = 47). Among the 52 patients who underwent a follow-up endoscopy, three gastric neoplasms were detected (one in the limited and two in the advanced EAG groups). During a median follow-up of 44 months, 10 (43.5%) patients in the limited and 13 (52.0%) in the advanced EAG groups showed EAG progression or newly occurred intestinal metaplasia. A family history of GC (odds ratio [OR] 44.974, 95% confidence interval [CI] 1.360-1487.087), a lower PGI/II (OR 0.247, 95% CI 0.085-0.717) and a longer follow-up duration (OR 1.832, 95% CI 1.200-2.796) increased the risk of progression.

CONCLUSION

A family history of GC and low baseline PGI/II were independently associated with an increased risk of progression of precursor lesions of GC.

Advanced non-cardia gastric cancer and Helicobacter pylori infection in Vietnam

Background

The incidence of gastric cancer in the Northern city, Hanoi is higher than in the Southern city, Ho Chi Minh, Vietnam. We previously reported that Helicobacter pylori vacA m1 genotype might be responsible for the difference between the two cities, however, the study only included non-cancer patients. The aim of this study is to investigate the non-cardia gastric cancer characteristics and the role of H. pylori virulence on different non-cardia gastric cancer incidence between two cities in Vietnam.

Methods and Results

We recruited 282 non-cardia gastric cancer patients that had undergone gastroscopy in two cities, Ho Chi Minh and Hanoi, Vietnam. Characteristics of non-cardia gastric cancer were late age of onset (mean age, 62.5 years), predominance in males (ratio of males/females; 3.9:1), diffuse type (55.3%), and high prevalence of H. pylori infection (79.4%). H. pylori infection and the vacA m1 genotype conferred an increased risk for GC (OR, 2.02; 95% CI 1.4–3.0; P = 0.0003 and OR, 2.7; 95% CI 1.5–4.7; P = 0.001, respectively). Interestingly, the presence of vacA m1 genotype in the gastric cancer group was significantly higher than that in the non-cancer group (68.8% vs 44.9%, P = 0.001) and the significant tendency still observed in Ho Chi Minh (67.6% vs 31.9%, P < 0.0001).

Conclusion

We first describe the characteristics of non-cardia gastric cancer in Vietnam. Helicobacter pylori infection was associated with the development of non-cardia GC. vacA m1 genotype might contribute to incidence differences between the two cities.

Electronic supplementary material

The online version of this article (doi:10.1186/s13099-017-0195-8) contains supplementary material, which is available to authorized users.

Gastric mucosal status in populations with a low prevalence of Helicobacter pylori in Indonesia

In Indonesia, endoscopy services are limited and studies about gastric mucosal status by using pepsinogens (PGs) are rare. We measured PG levels, and calculated the best cutoff and predictive values for discriminating gastric mucosal status among ethnic groups in Indonesia. We collected gastric biopsy specimens and sera from 233 patients with dyspepsia living in three Indonesian islands. When ≥5.5 U/mL was used as the best cutoff value of Helicobacter pylori antibody titer, 8.6% (20 of 233) were positive for H. pylori infection. PG I and II levels were higher among smokers, and PG I was higher in alcohol drinkers than in their counterparts. PG II level was significantly higher, whereas PG I/II ratios were lower in H. pylori-positive than in H. pylori-negative patients. PG I/II ratios showed a significant inverse correlation with the inflammation and atrophy scores of the antrum. The best cutoff values of PG I/II were 4.05 and 3.55 for discriminating chronic and atrophic gastritis, respectively. PG I, PG II, and PG I/II ratios were significantly lower in subjects from Bangli than in those from Makassar and Surabaya, and concordant with the ABC group distribution; however, group D (H. pylori negative/PG positive) was the lowest in subjects from Bangli. In conclusion, validation of indirect methods is necessary before their application. We confirmed that serum PG level is a useful biomarker determining chronic gastritis, but a modest sensitivity for atrophic gastritis in Indonesia. The ABC method should be used with caution in areas with a low prevalence of H. pylori.

Determining the cost-effectiveness of endoscopic surveillance for gastric cancer in patients with precancerous lesions

AIM

To identify the optimal strategy for gastric cancer (GC) prevention by evaluating the cost-effectiveness of esophagogastroduodenoscopy (EGD)-based preventive strategies.

METHODS

We conducted a model-based cost-effectiveness analysis. Adopting a healthcare payer's perspective, Markov models simulated the clinical experience of the target population (Singaporean Chinese 50-69 years old) undergoing endoscopic screening, endoscopic surveillance and usual care of do-nothing. The screening strategy examined the cohort every alternate year whereas the surveillance strategy provided annual EGD only to people with precancerous lesions. For each strategy, discounted lifetime costs ($) and quality adjusted life years (QALY) were estimated and compared to generate incremental cost-effectiveness ratio (ICER). Deterministic and probabilistic sensitivity analysis was conducted to identify influential parameters and quantify the impact of model uncertainties.

RESULTS

Annual EGD surveillance with an ICER of $34 200/QALY was deemed cost-effective for GC prevention within the Singapore healthcare system. To inform implementation, the models identified six influential factors and their respective thresholds, namely discount rate (<4.20%), age of starting surveillance (>51.6 years), proportion of program cost in delivering endoscopy (<65%), cost of follow-up EGD (<$484), utility of stage 1 GC patients (>0.72) and odds ratio of GC for high-risk subjects (>3.93). The likelihood that surveillance is the most cost-effective strategy is 69.5% accounting for model uncertainties.

CONCLUSION

Endoscopic surveillance of gastric premalignancies can be a cost-effective strategy for GC prevention. Its implementation requires careful assessment on factors influencing the actual cost-effectiveness.

Helicobacter pylori Infection and Gastric Mucosal Atrophy in Two Ethnic Groups in Nepal

Serum anti-Helicobacter pylori antibodies and pepsinogens (PGs) have been used as gastric cancer screening and gastric mucosal status markers. Nepal is a low risk country for gastric cancer. However, the mountainous populace in the northern region culturally linked to Tibet as well as Bhutan, a neighboring country, have a high risk of GC. We collected gastric biopsy specimens and sera from 146 dyspeptic patients living in Kathmandu, Nepal. We also examined the sera of 80 volunteers living in the mountainous regions of the Himalayas. The optimal cut-off was calculated for serum biomarkers against the histology. Kathmandu patients (43.8%) were serologically positive for H. pylori infection, which was significantly lower than that for the mountainous (61.3%, P = 0.01). The same results also found in the prevalence of PG-positivity, PG I levels and PG I/II ratios (P = 0.001, P <0.0001 and P = 0.03, respectively). Moreover, the PG I/II ratios were significantly, and inversely correlated with the OLGA score (r = -0.33, P <0.009). The low incidence of gastric cancer in Nepal can be attributed to low gastric mucosal atrophy. However, the mountainous subjects have high-risk gastric mucosal status, which could be considered a high-risk population in Nepal.

Biomarkers for Helicobacter pylori infection and gastroduodenal diseases

Helicobacter pylori infection is a major cause of gastric cancer. Although identifying H. pylori infected subjects is the first approach for delineating the high-risk population for gastric cancer, the presence of H. pylori antibodies is not sufficient for gastric cancer screening. Among H. pylori infected subjects, only a minority of infected individuals develop gastric cancer. Serologic markers of H. pylori infection can serve as potential predictors for the development of gastric cancer. Serum or urinary H. pylori antibodies, cytotoxin-associated gene A antibodies, pepsinogen and microRNAs were reported to be associated with precancerous lesions or gastric cancer. In this review, we summarized the utilities and limitations of each strategy.

Characteristics of gastric cancer in Asia

Gastric cancer (GC) is the fourth most common cancer in the world with more than 70% of cases occur in the developing world. More than 50% of cases occur in Eastern Asia. GC is the second leading cause of cancer death in both sexes worldwide. In Asia, GC is the third most common cancer after breast and lung and is the second most common cause of cancer death after lung cancer. Although the incidence and mortality rates are slowly declining in many countries of Asia, GC still remains a significant public health problem. The incidence and mortality varies according to the geographic area in Asia. These variations are closely related to the prevalence of GC risk factors; especially Helicobacter pylori (H. pylori) and its molecular virulent characteristics. The gradual and consistent improvements in socioeconomic conditions in Asia have lowered the H. pylori seroprevalence rates leading to a reduction in the GC incidence. However, GC remains a significant public health and an economic burden in Asia. There has been no recent systemic review of GC incidence, mortality, and H. pylori molecular epidemiology in Asia. The aim of this report is to review the GC incidence, mortality, and linkage to H. pylori in Asia.

Prevalence of Helicobacter pylori infection and atrophic gastritis in patients with dyspeptic symptoms in Myanmar

AIM: To survey the detailed analyses for Helicobacter pylori (H. pylori) infection and gastric mucosal status in Myanmar.

METHODS: A total of 252 volunteers with dyspeptic symptoms (155 female and 97 male; mean age of 43.6 ± 14.2 years) was participated in Yangon and Mandalay. The status of H. pylori infection was determined based on 5 different tests including rapid urease test, culture, histology, immunohistochemistry and serology. Histological scores were evaluated according to the update Sydney system and the Operative Link for Gastritis Assessment system. Pepsinogen (PG) I and PG II were measured using enzyme-linked immunosorbent assays.

RESULTS: The overall prevalence of H. pylori infection was 48.0%. There was no relationship between age and infection rate. Even in young group (less than 29 years old), the H. pylori infection rate was relatively high (41.9%). The prevalence of H. pylori infection was significantly higher in Yangon than that of Mandalay. H. pylori infection was significantly associated with the presence of gastric mucosal atrophy. All 7 subjects with peptic ulcer were infected with H. pylori. Although H. pylori-positive subjects showed stronger gastritis than H. pylori-negative subjects, most cases had mild gastritis.

CONCLUSION: We revealed the prevalence of H. pylori infection in patients with dyspeptic symptoms in Myanmar. The H. pylori infection was a risk factor for peptic ulcer and stronger gastritis.

Review article: Associations between Helicobacter pylori and obesity--an ecological study

BACKGROUND

There is emerging debate over the effect of Helicobacter pylori infection on body mass index (BMI). A recent study demonstrated that individuals who underwent H. pylori eradication developed significant weight gain as compared to subjects with untreated H. pylori colonisation.

AIM

To elucidate the association between H. pylori colonisation and the prevalence of overweight and obesity in developed countries.

METHODS

The literature was searched for publications reporting data on H. pylori prevalence rates and obesity prevalence rates. Studies selected reported H. pylori prevalence in random population samples with sample sizes of more than 100 subjects in developed countries (GDP >25,000 US$/person/year). Corresponding BMI distributions for corresponding countries and regions were identified. Nonparametric tests were used to compare the association between H. pylori and overweight and obesity rates.

RESULTS

Forty-nine studies with data from 10 European countries, Japan, the US and Australia were identified. The mean H. pylori rate was 44.1% (range 17-75%), the mean rates for obesity and overweight were 46.6 (± 16)% and 14.2 (± 8.9)%. The rate of obesity and overweight were inversely and significantly (r = 0.29, P < 0.001) correlated with the prevalence of H. pylori infection.

CONCLUSIONS

There is an inverse correlation between H. pylori prevalence and rate of overweight/obesity in countries of the developed world. Thus, the gradual decrease of the H. pylori colonisation that has been observed in recent decades (or factors associated with decrease of) could be causally related to the obesity endemic observed in the Western world.

Characteristics of gastric cancer in Asia

Gastric cancer (GC) is the fourth most common cancer in the world with more than 70% of cases occur in the developing world. More than 50% of cases occur in Eastern Asia. GC is the second leading cause of cancer death in both sexes worldwide. In Asia, GC is the third most common cancer after breast and lung and is the second most common cause of cancer death after lung cancer. Although the incidence and mortality rates are slowly declining in many countries of Asia, GC still remains a significant public health problem. The incidence and mortality varies according to the geographic area in Asia. These variations are closely related to the prevalence of GC risk factors; especially Helicobacter pylori (H. pylori) and its molecular virulent characteristics. The gradual and consistent improvements in socioeconomic conditions in Asia have lowered the H. pylori seroprevalence rates leading to a reduction in the GC incidence. However, GC remains a significant public health and an economic burden in Asia. There has been no recent systemic review of GC incidence, mortality, and H. pylori molecular epidemiology in Asia. The aim of this report is to review the GC incidence, mortality, and linkage to H. pylori in Asia.

A cost-effectiveness analysis evaluating endoscopic surveillance for gastric cancer for populations with low to intermediate risk

BACKGROUND

Gastric cancer (GC) surveillance based on oesophagogastroduodenoscopy (OGD) appears to be a promising strategy for GC prevention. By evaluating the cost-effectiveness of endoscopic surveillance in Singaporean Chinese, this study aimed to inform the implementation of such a program in a population with a low to intermediate GC risk.

METHODS

USING A REFERENCE STRATEGY OF NO OGD INTERVENTION, WE EVALUATED FOUR STRATEGIES: 2-yearly OGD surveillance, annual OGD surveillance, 2-yearly OGD screening and 2-yearly screening plus annual surveillance in Singaporean Chinese aged 50-69 years. From a perspective of the healthcare system, Markov models were built to simulate the life experience of the target population. The models projected discounted lifetime costs ($), quality adjusted life year (QALY), and incremental cost-effectiveness ratio (ICER) indicating the cost-effectiveness of each strategy against a Singapore willingness-to-pay of $46,200/QALY. Deterministic and probabilistic sensitivity analyses were used to identify the influential variables and their associated thresholds, and to quantify the influence of parameter uncertainties respectively.

RESULTS

With an ICER of $44,098/QALY, the annual OGD surveillance was the optimal strategy while the 2-yearly surveillance was the most cost-effective strategy (ICER = $25,949/QALY). The screening-based strategies were either extendedly dominated or cost-ineffective. The cost-effectiveness heterogeneity of the four strategies was observed across age-gender subgroups. Eight influential parameters were identified each with their specific thresholds to define the choice of optimal strategy. Accounting for the model uncertainties, the probability that the annual surveillance is the optimal strategy in Singapore was 44.5%.

CONCLUSION

Endoscopic surveillance is potentially cost-effective in the prevention of GC for populations at low to intermediate risk. Regarding program implementation, a detailed analysis of influential factors and their associated thresholds is necessary. Multiple strategies should be considered in order to recommend the right strategy for the right population.

Helicobacter pylori infection--a boon or a bane: lessons from studies in a low-prevalence population

Helicobacter pylori (H. pylori) infection is etiologically associated with gastric cancer and peptic ulcer diseases which are both important public health burdens which could be largely eliminated by H. pylori eradication. However, some investigators urge caution based on the hypothesis that eradication of H. pylori may result in an increase in the incidence of gastroesophageal reflux disease, esophageal adenocarcinoma, and childhood asthma. The ethnic Malays of northeastern Peninsular Malaysia have long had a low prevalence of H. pylori infection and, as expected, the incidence of gastric cancer and its precursor lesions is exceptionally low. The availability of a population with a low H. pylori prevalence and generally poor sanitation allows separation of H. pylori from the hygiene hypothesis and direct testing of whether absence of H. pylori is associated with untoward consequence. Contrary to predictions, in Malays, erosive esophagitis, Barrett's esophagus, distal esophageal cancers, and childhood asthma are all of low incidence. This suggests that H. pylori is not protective rather the presence of H. pylori infection is likely a surrogate for poor hygiene and not an important source of antigens involved in the hygiene hypothesis. Helicobacter pylori in Malays is related to transmission from H. pylori-infected non-Malay immigrants. The factors responsible for low H. pylori acquisition, transmission, and burden of H. pylori infection in Malays remain unclear and likely involves a combination of environmental, host (gene polymorphisms), and strain virulence factors. Based on evidence from this population, absence of H. pylori infection is more likely to be boon than a bane.

Comparison of the virulence markers of Helicobacter pylori and their associated diseases in patients from Pakistan and Afghanistan

BACKGROUND/AIM

Helicobacter pylori is a Gram-negative bacteria, which is associated with development of gastroduodenal diseases. The prevalence of H. pylori and the virulence markers cytotoxin-associated gene A and E (cagA, cagE) and vacuolating-associated cytotoxin gene (vacA) alleles varies in different parts of the world. H. pylori virulence markers cagA, cagE, and vacA alleles in local and Afghan nationals with H. pylori-associated gastroduodenal diseases were studied.

PATIENTS AND METHODS

Two hundred and ten patients with upper gastrointestinal symptoms and positive for H. pylori by the urease test and histology were included. One hundred and nineteen were local nationals and 91 were Afghans. The cagA, cagE, and vacA allelic status was determined by polymerase chain reaction.

RESULTS

The nonulcer dyspepsia (NUD) was common in the Afghan patients (P = 0.025). In Afghan H. pylori strains, cagA was positive in 14 (82%) with gastric carcinoma (GC) compared with 29 (45%) with NUD (P = 0.006), whereas cagE was positive in 11 (65%) with GC and 4 (67%) with duodenal ulcer (DU) compared with 12 (18%) with NUD (P < 0.001 and 0.021, respectively). The vacA s1a/b1was positive in 10 (59%) of GC compared with 20 (31%) in NUD (P = 0.033). In Pakistani strains, cagE was positive in 12 (60%) with GC, 7 (58%) with GU, 12 (60%) with DU compared with 11 (16%) with NUD (P < 0.001, 0.004, and < 0.001, respectively). In Pakistani strains, cagA/s1a/m1 was 39 (33%) compared with Afghans in 17 (19%) (P = 0.022). Moderate to severe mucosal inflammation was present in 51 (43%) Pakistani patients compared with 26 (28%) (P = 0.033) in Afghans. It was also associated with grade 1 lymphoid aggregate development in Pakistani patients 67 (56%) compared with 36 (40%) (P = 0.016) in Afghans.

CONCLUSION

Distribution of H. pylori virulence marker cagE with DU was similar in Afghan and Pakistan H. pylori strains. Chronic active inflammation was significantly associated with Pakistani H. pylori strains.

Seroprevalence of Helicobacter pylori infection and gastric mucosal atrophy in Bhutan, a country with a high prevalence of gastric cancer

Gastric cancer is the second leading cause of cancer-related mortality in the world. Recently, serum Helicobacter pylori antibodies and pepsinogen (PG) have been used for gastric cancer screening. The incidence of gastric cancer in Bhutan is reported to be quite high compared with that in neighbouring countries. In this study, 381 subjects from three areas of Bhutan were assessed for gastric mucosal atrophy and serological parameters. Anti-H. pylori IgG, PG I, PG II and cytotoxin-associated gene A (CagA) antibodies were measured using ELISA. Subjects were classified into four groups according to H. pylori and PG seropositivity: Group A (H. pylori-negative/PG-negative), Group B (H. pylori-positive/PG-negative), Group C (H. pylori-positive/PG-positive) and Group D (H. pylori-negative/PG-positive). The prevalence of H. pylori in the 381 subjects was 71.1% (271/381), with high infection rates found in rural areas. The PG I/II ratio was significantly inversely correlated with the atrophy score in the antrum and the corpus (P<0.001). Multivariate analysis showed that the PG status was significantly associated with the presence of atrophy in the corpus. The prevalence of the PG-positive status was significantly higher among H. pylori-positive subjects than among H. pylori-negative subjects (P<0.001). Based on the ABC method, Group B was the most dominant, followed by Group A, Group C and Group D. The high incidence of gastric cancer in Bhutan can be attributed to the high prevalence of H. pylori infection and gastric mucosal atrophy.

Validation of the functional assessment of cancer therapy-gastric module for the Chinese population

Background

Quality of life (QoL) assessment has become an important aspect of the clinical management of gastric cancer (GC), which poses a greater health threat in Chinese populations around the world. Functional Assessment of Cancer Therapy-Gastric Module (FACT-Ga), a questionnaire developed specifically to measure QoL of patients with GC, has never been validated in Chinese subjects. The current study was designed to examine the psychometric properties of FACT-Ga as a GC specific QoL instrument for its future use in Chinese populations.

Methods

A sample of 67 Chinese patients with GC in the National University Hospital, Singapore was investigated cross-sectionally. The participants independently completed either English or Chinese versions of the FACT-Ga and the European Quality of Life-5 Dimensions (EQ-5D). Reliability was measured as the Cronbach’s α for EQ-5D, and five subscale scores and two total scores of FACT-Ga. The sensitivity to patients’ clinical status was evaluated by comparing EQ-5D and FACT-Ga scores between clinical subgroups classified by Clinical Stage and Treatment Intent. The construct validity of FACT-Ga was assessed internally by examining the item-to-scale correlations and externally by contrasting the FACT-Ga subscales with the EQ-5D domains.

Results

For both FACT-Ga and EQ-5D, patients treated with curative intent rated their QoL higher than those treated for palliation, and early stage patients scored higher than those in the late stage. The sensitivity to clinical status of FACT-Ga scores were differential as four of seven FACT-Ga scores were significant for Treatment Intent while only one subscale score was significant for Clinical Stage. Six FACT-Ga scores had Cronbach’s α of 0.8 or above indicating excellent reliability. For construct validity, 45 of 46 items converged about their respective subscales. The monotrait-multimethod correlations between QoL constructs of FACT-Ga and EQ-5D were stronger than the multitrait-multimethod correlations as theoretically hypothesized, suggesting good convergent and discriminant validities.

Conclusions

Given the excellent reliability and good construct validity, FACT-Ga scores are able to distinguish patient groups with different clinical characteristics in the expected direction. Therefore FACT-Ga can be used as a discriminative instrument for measuring QoL of Chinese patients with GC.

2D-DIGE analysis of sera from transgenic mouse models reveals novel candidate protein biomarkers for human gastric cancer

The gp130(F/F) genetically engineered mouse (GEM) model reproducibly and predictably develops a gastric adenoma phenotype resembling the primary lesions of human intestinal-type gastric cancer (GC). Accordingly, changes to the serum proteome of gp130(F/F) mice may uncover early-stage GC biomarkers. Here, we have employed several double and compound mutant GEM strains that display distinct phenotypes with respect to gastric tumour load and inflammatory response, thereby mimicking different states of inflammation-associated early-stage GC in humans. This allowed us to distinguish between proteomic changes associated with tumourigenesis rather than confounding systemic inflammation. The comparative proteomic workflow involved depletion of high abundance proteins, 2D-DIGE analysis and protein identification by LC-MS/MS. The differential expression of 112 2D-DIGE spots specifically correlated with the tumour-bearing phenotype, corresponding to 31 murine proteins and their 28 human orthologues. Eight proteins were selected for validation in GC patient sera versus healthy controls. Significant increases in serum apolipoprotein E and haptoglobin, and decreases in afamin and clusterin, were confirmed by ELISA. Receiver operating characteristic analysis revealed that these proteins may be more sensitive and specific discriminators of GC than the existing clinical marker CA72-4.

Sociocultural and dietary practices among Malay subjects in the north-eastern region of Peninsular Malaysia: a region of low prevalence of Helicobacter pylori infection

BACKGROUND AND AIM

The prevalence of Helicobacter pylori infection is exceptionally low among the Malays in the north-eastern region of Peninsular Malaysia. The reasons are unknown. Our aim was to compare environmental factors that differed in relation to H. pylori prevalence among Malays born and residing in Kelantan.

METHODS

A case-control study was conducted among Malays in Kelantan who underwent upper endoscopy between 2000 and 2008. Helicobacter pylori status was determined by gastric histology. Sociocultural and dietary factors were assessed using a validated investigator-directed questionnaire administered after 2008, and the data were analyzed using logistic regression analysis.

RESULTS

The study group consisted of 161 subjects (79 H. pylori positive and 82 controls). Univariable analysis identified five poor sanitary practices associated with an increased prevalence of H. pylori infection: use of well water, use of pit latrine, less frequent boiling of drinking water, and infrequent hand wash practice after toilet use and before meals. Multivariable logistic regression analysis identified three variables inversely associated with H. pylori infection: frequent consumption of tea (OR: 0.023, 95% CI: 0.01-0.07), frequent use of "budu" or local anchovy sauce (OR: 0.09, 95% CI: 0.1-0.7), and frequent use of "pegaga" or centenella asiatica (OR: 0.25, 95% CI: 0.1-0.65).

CONCLUSIONS

Under the assumption that sanitary, sociocultural, and dietary habits have not changed over the years, we can conclude that an increased risk of H. pylori was associated with unsanitary practices whereas protection was associated with consumption of tea and locally produced foods, "pegaga" and "budu." These dietary factors are candidates for future study on the effects on H. pylori transmission.

Race, African ancestry, and Helicobacter pylori infection in a low-income United States population

BACKGROUND

Gastric cancer incidence in African Americans is twice that of whites, and differing prevalence of Helicobacter pylori strain-specific isolates may help explain the disparity.

METHODS

Serum levels of antibodies to each of 15 H. pylori proteins were assessed using multiplex serology for a sample of 689 African American and white participants from the Southern Community Cohort Study. African and European admixture was estimated using a panel of 276 ancestry genetic markers, with "low," "medium," and "high" categories of African ancestry defined as <85%, 85% to 95%, and ≥95%.

RESULTS

The majority (79%) of our study population were sero-positive for H. pylori. African American race was associated with a two- to sixfold increased odds for sero-positivity to eight H. pylori proteins, including the cancer-associated virulence constituents CagA [odds ratio (OR), 6.4; 95% CI, 4.5-9.1], and VacA (OR, 2.3; 95% CI, 1.5-3.5). Compared to whites, African Americans of low, medium, and high African ancestry had 1.6-, 4.1-, and 5.2-fold increased odds of sero-positivity to H. pylori, primarily related to CagA sero-positive strains, for which increasing African ancestry led to 2.5-, 9.6-, and 13.1-fold increased odds. Among African Americans alone, compared to those of low African ancestry, African Americans of medium and high African ancestry had 2.5- and 3.4-fold increased odds of sero-positivity to H. pylori, and 3.5- and 4.9-fold increased odds of CagA sero-positive H. pylori strains.

CONCLUSIONS

Host genetic variation and/or lifestyle factors associated with African ancestry contribute to the likelihood of infection with H. pylori, particularly its virulent strains, in this low-income U.S. southern population.

IMPACT

Our findings that low-income African Americans of high African ancestry have a particularly high prevalence of antibodies against H. pylori provides a framework for further research into better detection and prevention of gastric cancer in this population.

The role of serum pepsinogen in the detection of gastric cancer

The incidence of gastric cancer is very high in Japan, Korea, and China. Reducing the morbidity and mortality associated with gastric cancer requires early diagnosis, which can be facilitated by applying gastroscopy more frequently in high-risk groups. A strategy of population screening for gastric cancer is currently being adopted in Korea, Japan, and the Matsu region of Taiwan, but using different screening methods. In addition, the history of pepsinogen (PG) in research as a gastric cancer biomarker has varied, in that the use of serum levels of PGI and PGII and the PGI/PGII ratio as gastric cancer screening tools was introduced in Japan before 1990, but in Korea the first research results were only reported in 2008. This review first evaluates the physiology of PG, followed by the usefulness or limitations of serum PG testing with regard to the detection of gastric cancer. Finally, the factors affecting the efficacy of PG tests as a gastric cancer biomarker (i.e., Helicobacter pylori infection status, gender, histopathologic features, and cancer location and depth) are evaluated. It was found that the strategies used to increase the efficacy of PG tests should be individualized in each country according to the seroprevalence of H. pylori.

Epidemiology of Helicobacter pylori infection and gastric cancer in Asia

In Asia, the prevalence of Helicobacter pylori (H. pylori) infection varies markedly in different countries. Higher prevalence rates are found in developing Asian countries while lower rates have been reported in more industrialized and developed countries. Within a country, the seroprevalence rates may vary between distinct geographic regions. H. pylori infection is an important etiological factor for the occurrence of non-cardia gastric adenocarcinoma. The incidence rate of gastric adenocarcinoma in Asia tends to mirror the seroprevalence rate of H. pylori infection; however, there are populations with high seroprevalence rates of H. pylori infection that paradoxically have low incidence rates of gastric adenocarcinoma. These diverse clinical outcomes are related to bacterial virulence factors, concomitant environmental factors, host susceptibility and immune response. This review summarizes the current epidemiology of H. pylori infection in Asia and analyzes these data in the context of gastric cancer epidemiology.

Distinct cagA EPIYA motifs are associated with ethnic diversity in Malaysia and Singapore

BACKGROUND

In vitro studies have shown that the biologic activity of CagA is influenced by the number and class of EPIYA motifs present in its variable region as these motifs correspond to the CagA phosphorylation sites. It has been hypothesized that strains possessing specific combinations of these motifs may be responsible for gastric cancer development. This study investigated the prevalence of cagA and the EPIYA motifs with regard to number, class, and patterns in strains from the three major ethnic groups within the Malaysian and Singaporean populations in relation to disease development.

MATERIALS AND METHODS

Helicobacter pylori isolates from 49 Chinese, 43 Indian, and 14 Malay patients with functional dyspepsia (FD) and 21 gastric cancer (GC) cases were analyzed using polymerase chain reaction for the presence of cagA and the number, type, and pattern of EPIYA motifs. Additionally, the EPIYA motifs of 47 isolates were sequenced.

RESULTS

All 126 isolates possessed cagA, with the majority encoding EPIYA-A (97.6%) and all encoding EPIYA-B. However, while the cagA of 93.0% of Indian FD isolates encoded EPIYA-C as the third motif, 91.8% of Chinese FD isolates and 81.7% of Chinese GC isolates encoded EPIYA-D (p < .001). Of Malay FD isolates, 61.5% and 38.5% possessed EPIYA-C and EPIYA-D, respectively. The majority of isolates possessed three EPIYA motifs; however, Indian isolates were significantly more likely to have four or more (p < .05).

CONCLUSION

Although, H. pylori strains with distinct cagA-types are circulating within the primary ethnic groups resident in Malaysia and Singapore, these genotypes appear unassociated with the development of GC in the ethnic Chinese population. The phenomenon of distinct strains circulating within different ethnic groups, in combination with host and certain environmental factors, may help to explain the rates of GC development in Malaysia.

Clinical significance of IgG antibody titer against Helicobacter pylori

BACKGROUND

We clarified the clinical significance of measurement of IgG antibody titers against Helicobacter pylori using data from a nested case-control study from a large-scale cohort study in Japan.

METHOD

Participants included 36,745 subjects from the Japan Health Center-based Prospective Study who responded to the baseline questionnaire and provided a blood sample. Subjects were aged 40-69 years and were followed over 15 years after initial sampling. Controls were matched to 511 gastric cancer patients. Plasma surface antigen (Hp)-IgG titer was measured using ELISA, and mucosal atrophy was determined by measuring pepsinogen I and II levels.

RESULTS

Seropositive subjects with low Hp-IgG titer and mucosal atrophy showed a higher risk for gastric cancer than high-titer subjects. Odds ratio (OR) referred to cases with true negative IgG titers and no mucosal atrophy. In moderately atrophic subjects, the low titer OR was 19.0, with a 95% confidence interval (CI) of 7.7-46.9, and 12.5 for high titer, with a 95% CI of 5.2-30.0. In severely atrophic subjects, the low titer OR was almost double that of high-titer subjects (OR = 30.2, 95% CI = 12.4-73.7 and OR = 15.9, 95% CI = 6.3-40.3, respectively). These associations were observed more frequently for differentiated than undifferentiated gastric cancer.

CONCLUSION

Combination assay with Hp-IgG titer and pepsinogens may help identify groups at high risk for gastric cancer. Subjects with low Hp-IgG titer and mucosal atrophy were at extremely high risk for gastric cancer, particularly differentiated cancer. Subjects with this background may require ongoing observation and periodic endoscopic examination for early cancer detection.

Comparison of the validity of three biomarkers for gastric cancer screening: carcinoembryonic antigen, pepsinogens, and high sensitive C-reactive protein

PURPOSE

To identify a desirable serum marker for screening tools for gastric cancer, we evaluated the validity of 3 biomarkers, namely, carcinoembryonic antigen (CEA), pepsinogens (PGs), and high sensitive C-reactive protein (hsCRP).

METHODS

We estimated the mean serum levels of CEA, PGs, and hsCRP and compared the sensitivity and specificity of these 3 biomarkers in 378 subjects who were classified into 7 groups: normal, chronic atrophic gastritis, intestinal metaplasia, adenoma, early gastric cancer (EGC), advanced gastric cancer (AGC) without metastasis, and AGC with metastasis (M1).

RESULTS

There were no significant differences among the normal, high-risk (chronic atrophic gastritis, intestinal metaplasia, and adenoma), and EGC groups for CEA and hsCRP. However, the levels of CEA were relatively higher in the AGC group with intestinal-type cancer (P<0.01). Likewise, hsCRP was relatively higher in the AGC group with diffuse-type cancer (P<0.01). For the PG I/II ratio, there was no significant difference among the normal, high-risk, and cancer groups, including EGC (P<0.01). In addition, there was a negative correlation with grades (gammas=-0.480, P<0.01). However, the PG I/II ratio was relatively less effective in diffuse-type cancer compared with intestinal-type cancer. The combination of serum hsCRP and the PG I/II ratio had a higher sensitivity (77%) than did the PG I/II ratio alone (61%) in diffuse-type cancers.

CONCLUSIONS

The combination of serum hsCRP and PG I/II ratio would be helpful as a screening tool for gastric cancer in high incidence populations and may help to select high-risk subjects in need of further specific invasive screening tools such as endoscopy.

Association of Helicobacter pylori infection with chronic atrophic gastritis: Meta-analyses according to type of disease definition

Helicobacter pylori is a major risk factor for chronic atrophic gastritis (CAG). A large variety of definitions of CAG have been used in epidemiologic studies in the past. The aim of this work was to systematically review and summarize estimates of the association between H. pylori infection and CAG according to the various definitions of CAG. Articles on the association between H. pylori infection and CAG published until July 2007 were identified. Separate meta-analyses were carried out for studies defining CAG based on gastroscopy with biopsy, serum pepsinogen I (PG I) only, the pepsinogen I/pepsinogen II ratio (PG I/PG II ratio) only, or a combination of PG I and the PG I/PG II ratio. Numbers of identified studies and summary odds ratios (OR) (95% confidence intervals) were as follows: gastroscopy with biopsy: n = 34, OR = 6.4 (4.0-10.1); PG I only: n = 13, OR = 0.9 (0.7-1.2); PG I/PG II ratio: n = 8, OR = 7.2 (3.1-16.8); combination of PG I and the PG I/PG II ratio: n = 20, OR = 5.7 (4.4-7.5). Studies with CAG definitions based on gastroscopy with biopsy or the PG I/PG II ratio (alone or in combination with PG I) yield similarly strong associations of H. pylori with CAG. The association is missed entirely in studies where CAG is defined by PG I only.

Cost-effectiveness analysis of Helicobacter pylori screening in prevention of gastric cancer in Chinese

OBJECTIVES

The aim of this study was to evaluate the costs and effectiveness associated with no screening, Helicobacter pylori serology screening, and the 13C-urea breath test (UBT) for gastric cancer in the Chinese population.

METHODS

A Markov model simulation was carried out in Singaporean Chinese at 40 years of age (n = 478,500) from the perspective of public healthcare providers. The main outcome measures were costs, number of gastric cancer cases prevented, life-years saved, quality-adjusted life-years (QALYs) gained from the screening age to death, and incremental cost-effectiveness ratios (ICERs), which were compared among the three strategies. The uncertainty surrounding ICERs was addressed by scenario analyses and probabilistic sensitivity analysis using Monte Carlo simulation.

RESULTS

The ICER of serology screening versus no screening was $25,881 per QALY gained (95 percent confidence interval (95 percent CI), $5,700 to $120,000). The ICER of UBT versus no screening was $53,602 per QALY gained (95 percent CI, $16,000 to $230,000). ICER of UBT versus serology screening was $470,000 per QALY gained, for which almost all random samples of the ICERs distributed above $50,000 per QALY.

CONCLUSIONS

It cannot be confidently concluded that either H pylori screening was a cost-effective strategy compared with no screening in all Chinese at the age of 40 years. Nevertheless, serology screening has demonstrated much more potential to be a cost-effective strategy, especially in the population with higher gastric cancer prevalence.

Asia-Pacific consensus guidelines on gastric cancer prevention

BACKGROUND AND AIM

Gastric cancer is a major health burden in the Asia-Pacific region but consensus on prevention strategies has been lacking. We aimed to critically evaluate strategies for preventing gastric cancer.

METHODS

A multidisciplinary group developed consensus statements using a Delphi approach. Relevant data were presented, and the quality of evidence, strength of recommendation, and level of consensus were graded.

RESULTS

Helicobacter pylori infection is a necessary but not sufficient causal factor for non-cardia gastric adenocarcinoma. A high intake of salt is strongly associated with gastric cancer. Fresh fruits and vegetables are protective but the use of vitamins and other dietary supplements does not prevent gastric cancer. Host-bacterial interaction in H. pylori infection results in different patterns of gastritis and differences in gastric acid secretion which determine disease outcome. A positive family history of gastric cancer is an important risk factor. Low serum pepsinogens reflect gastric atrophy and may be useful as a marker to identify populations at high risk for gastric cancer. H. pylori screening and treatment is a recommended gastric cancer risk reduction strategy in high-risk populations. H. pylori screening and treatment is most effective before atrophic gastritis has developed. It does not exclude the existing practice of gastric cancer surveillance in high-risk populations. In populations at low risk for gastric cancer, H. pylori screening is not recommended. First-line treatment of H. pylori infection should be in accordance with national treatment guidelines.

CONCLUSION

A strategy of H. pylori screening and eradication in high-risk populations will probably reduce gastric cancer incidence, and based on current evidence is recommended by consensus.

Accuracy of endoscopic ultrasound staging of gastric cancer in routine clinical practice in Singapore

OBJECTIVE

Endoscopic ultrasound has emerged as the leading modality to assess the T and N stage in gastric cancer. This study aimed to assess the accuracy of TN staging by endoscopic ultrasound in routine clinical practice in Singapore.

METHODS

Over a period of 7 years, 77 patients (male: 70%; median age 62.8 years) with gastric cancer underwent preoperative staging with endoscopic ultrasound. Fifty-seven patients eventually underwent surgery with tissues available for histopathological staging and comparison.

RESULTS

The tumor locations were: cardia: 13; corpus: 20; incisura: 19; antrum: 25. The majority was poorly differentiated (57.1%); 26% were moderately differentiated and 16.9% were well differentiated adenocarcinoma. Compared to pathological staging, the overall accuracy of T staging by endoscopic ultrasound was 77.2% (17.5% under-staged: 5.3% over-staged). The staging accuracy of T1 (92.9%) and T3 (81.8%) was higher than T2 (57.1%) and T4. For N staging, the accuracy of endoscopic ultrasound was 59.6% (26.3% under-staged; 14% over-staged); this was significantly superior to computer tomography (43.9%).

CONCLUSION

Endoscopic ultrasound is useful for the T staging of gastric cancer, with an overall accuracy rate of 77%, and up to 93% for T1 lesions. Under-staging may occur due to microscopic tumor infiltration, while over-staging may arise due to inflammatory reactions. The accuracy of N staging is lower at 60%, but could be further improved with the use of fine needle aspiration.

Ethnicity and H. pylori as risk factors for gastric cancer in Malaysia: A prospective case control study

OBJECTIVE

To determine the risk factors for gastric cancer (GCA), with particular emphasis on ethnicity in our multiracial population.

METHODS

A prospective case control study with ratio of cancer:controls of 1:2. Diagnosis of H. pylori was made by serology using the ELISA technique. Dietary intake was assessed by dietary recall over the preceding 6 months.

RESULTS

Eighty-seven cases of GCA were enrolled. The cancers were predominantly distal in location and of the intestinal type. Risk factors identified following multiple logistic regression analysis were: Chinese race (OR 10.23 [2.87-36.47]), H. pylori (OR 2.54 [1.16-5.58]), low level of education (OR 9.81 [2.03-47.46]), smoking (OR 2.52 [1.23-5.15]), and high intake of salted fish and vegetables (OR 5.18 [1.35-20.00]) were identified as significant independent risk factors for GCA, while high intake of fresh fruits and vegetables was protective for GCA (OR 0.15 [0.04-0.64]). Chili intake was not a significant protective factor following multivariate analysis.

CONCLUSIONS

Chinese race was a strong independent predictor of GCA. H. pylori was an important predictor of GCA with a 2.5-fold greater risk in our patients. Despite a high prevalence of H. pylori, the prevalence of GCA among Indians was low and this paradox can be appropriately called the "Indian enigma."

Non-invasive diagnosis of gastric mucosal atrophy in an asymptomatic population with high prevalence of gastric cancer

AIM: To validate a non-invasive method to detect gastric mucosal atrophy in a Chilean population with high prevalence of gastric cancer and a poor survival rate.

METHODS: We first determined the optimal cut-off level of serum pepsinogen (PG)-1, PG-1/PG-2 ratio and 17-gastrin in 31 voluntary symptomatic patients (mean age: 66.1 years), of them 61% had histologically confirmed gastric atrophy. Then, in a population-based sample of 536 healthy individuals (209 residents in counties with higher relative risk and 327 residents in counties with lower relative risk for gastric cancer), we measured serum anti-H pylori antibodies, PG and 17-gastrin and estimated their risk of gastric cancer.

RESULTS: We found that serum PG-1 < 61.5 μg/L, PG-1/PG-2 ratio < 2.2 and 17-gastrin > 13.3 pmol/L had a high specificity (91%-100%) and a fair sensitivity (56%-78%) to detect corpus-predominant atrophy. Based on low serum PG-1 and PG-1/PG-2 ratio together as diagnostic criteria, 12.5% of the asymptomatic subjects had corpus-predominant atrophy (0% of those under 25 years and 20.2% over 65 years old). The frequency of gastric atrophy was similar (12% vs 13%) but H pylori infection rate was slightly higher (77% vs 71%) in the high-risk compared to the low-risk counties. Based on their estimated gastric cancer risk, individuals were classified as: low-risk group (no H pylori infection and no atrophy; n = 115; 21.4%); moderate-risk group (H pylori infection but no atrophy; n = 354, 66.0%); and high-risk group (gastric atrophy, with or without H pylori infection; n = 67, 12.5%). The high-risk group was significantly older (mean age: 61.9 ± 13.3 years), more frequently men and less educated as compared with the low-risk group.

CONCLUSION: We propose to concentrate on an upper gastrointestinal endoscopy for detection of early gastric cancer in the high-risk group. This intervention model could improve the poor prognosis of gastric cancer in Chile.