Optimal cutoff value of the serum pepsinogen level for prediction of gastric cancer incidence: the Hisayama Study

Site-specific protein biomarkers in gastric cancer: a comprehensive review of novel biomarkers and clinical applications

INTRODUCTION

Gastric cancer (GC) is the fifth most common cancer and the fourth leading cause of cancer-related death worldwide, thus representing a significant global health burden. Early detection and monitoring of GC are essential to improve patient outcomes. While traditional cancer biomarkers such as carcinoembryonic antigen, carbohydrate antigen (CA) 19-9, and CA 72-4 are widely used, their limited sensitivity and specificity necessitate the exploration of alternative biomarkers.

AREAS COVERED

This review comprehensively analyzes the landscape of GC protein biomarkers identified from 2019 to 2022, with a focus on tissue, blood, urine, saliva, gastric juice, ascites, and exhaled breath as sample sources. We address the potential clinical applications of these biomarkers in early diagnosis, monitoring recurrence, and predicting survival and therapeutic response of GC patients.

EXPERT OPINION

The discovery of novel protein biomarkers holds great promise for improving the clinical management of GC. However, further validation in large, diverse cohorts is needed to establish the clinical utility of these biomarkers. Integrating these biomarkers with existing diagnostic and monitoring approaches will likely lead to improved personalized treatment plans and patient outcomes.

Serum Pepsinogen as a Biomarker for Gastric Cancer in the United States: A Nested Case-Control Study Using the PLCO Cancer Screening Trial Data

BACKGROUND

Gastric cancer lacks specific symptoms, resulting in diagnosis at later stages and high mortality. Serum pepsinogen is a biomarker for atrophic gastritis, a gastric cancer precursor, and may be useful to detect persons at increased risk of gastric cancer.

METHODS

The Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial was conducted in the United States between 1993 and 2001. ELISA-based pepsinogen tests were conducted on prediagnostic serum samples of 105 PLCO participants who developed gastric cancer and 209 age, sex, and race-matched controls. Pepsinogen positive (PG+) was defined as pepsinogen I ≤ 70 μg/L and pepsinogen I/II ratio ≤3.0. Results of conditional logistic regression models, and sensitivity and specificity, of PG+ for gastric cancer are reported.

RESULTS

Gastric cancer cases were more likely to be PG+ (31.4% vs. 5.5%, P < 0.001) at baseline than controls. Compared to PG-, PG+ was associated with an 8.5-fold increased risk for gastric cancer [95% confidence interval (CI) = 3.8-19.4]. This risk remained significant after adjusting for Helicobacter pylori, family history of gastric cancer, education, smoking, and BMI (aOR, 10.6; 95% CI, 4.3-26.2). In subgroup analysis, PG+ individuals were 11-fold more like to develop non-cardia gastric cancer (OR, 11.1; 95% CI, 4.3-28.8); conversely, they were not significantly more likely to develop cardia gastric cancer (OR, 2.0; 95% CI = 0.3-14.2). PG+ status yielded low sensitivity but high specificity for both noncardia (44.3%; 93.6%) and cardia gastric cancer (5.7%; 97.2%).

CONCLUSIONS

Prediagnostic serum pepsinogen levels from a large, prospective cohort study were associated with risk of gastric cancer, particularly noncardia gastric cancer.

IMPACT

PG status may identify individuals at higher risk of noncardia gastric cancer for targeted screening or interventions. See related commentary by Zhou and Huang, p. 1257.

Novel Biomarkers of Gastric Adenocarcinoma: Current Research and Future Perspectives

Simple Summary

Gastric cancer is characterized by poor survival rates despite surgery and chemotherapy. Current research focuses on biomarkers to improve diagnosis and prognosis, and to enable targeted treatment strategies. The aim of our review was to give an overview over the wide range of novel biomarkers in gastric cancer. These biomarkers are targets of a specific treatment, such as antibodies against human epidermal growth factor receptor 2. Other promising biomarkers for targeted therapies that have shown relevance in clinical trials are vascular endothelial growth factor, programmed cell death protein 1, and Claudin 18.2. There is a vast number of biomarkers based on DNA, RNA, and protein expression, as well as detection of circulating tumor cells and the immune tumor microenvironment.

Abstract

Overall survival of gastric cancer remains low, as patients are often diagnosed with advanced stage disease. In this review, we give an overview of current research on biomarkers in gastric cancer and their implementation in treatment strategies. The HER2-targeting trastuzumab is the first molecular targeted agent approved for gastric cancer treatment. Other promising biomarkers for targeted therapies that have shown relevance in clinical trials are VEGF and Claudin 18.2. Expression of MET has been shown to be a negative prognostic factor in gastric cancer. Targeting the PD-1/PD-L1 pathway with immune checkpoint inhibitors has proven efficacy in advanced gastric cancer. Recent technology advances allow the detection of circulating tumor cells that may be used as diagnostic and prognostic indicators and for therapy monitoring in gastric cancer patients. Prognostic molecular subtypes of gastric cancer have been identified using genomic data. In addition, transcriptome profiling has allowed a comprehensive characterization of the immune and stromal microenvironment in gastric cancer and development of novel risk scores. These prognostic and predictive markers highlight the rapidly evolving field of research in gastric cancer, promising improved treatment stratification and identification of molecular targets for individualized treatment in gastric cancer.

Clinical Value of Pepsinogen in the Screening, Prevention, and Diagnosis of Gastric Cancer

OBJECTIVES

To compare the levels of serum pepsinogen (PG) in patients with gastric cancer (GC), patients with atrophic gastritis (AG), and healthy donors. Also, we explored the clinical value of PG detection for the diagnosis and treatment of GC.

METHODS

The PG level in peripheral blood from patients and heathy donors was determined using an Abbott automatic chemiluminescence instrument. The study included 117 patients with GC confirmed by gastroscopy and histopathology, of whom 13 patients had cancer at stage I, 47 at stage II, 41 at stage III, and 16 at stage IV. The AG group included 122 patients, and the control group had 120 healthy donors. The relationship between serum PG levels and the occurrence and development of GC, as well as the evaluation of the clinical value of diagnostic tests based on serum PG detection, were investigated by receiver operating characteristic (ROC) curve analyses.

RESULTS

Pepsinogen I (PGI) levels gradually decreased from the control group, the AG group, and the GC group. PGI exhibited high diagnostic value for GC (area under the curve [AUC], 0.834; cutoff, 51.2 ng/mL, sensitivity, 81.7%; specificity, 68.4%), PGII (AUC, 0.587; cutoff value, 13.05 ng/mL; sensitivity, 65.8%; specificity, 53.8%), and PGR (AUC, 0.752; cutoff, 5.65; sensitivity, 54.2%; specificity, 87.2%). The occurrence of GC was negatively correlated with serum levels of PGI (B = -0.054; OR = 0.947; 95% confidence interval [CI], 0.925-0.970; P <.001) and PGR (B = -0.420; OR = 0.657; 95% CI, 0.499-0.864; P = .003).

CONCLUSIONS

The combined detection of PGI, PGII, and PGR has important clinical value for the screening, prevention, and diagnosis of GC and could allow for earlier detection, diagnosis, and treatment of GC.

The Role of Helicobacter pylori and Serum Pepsinogen Levels in Metachronous Gastric Cancer After Endoscopic Gastrectomy

PURPOSE

The current study aimed to explore the role of Helicobacter pylori (Hp) infection and serum pepsinogen (PG) levels in the occurrence of metachronous gastric cancer after endoscopic gastrectomy.

MATERIALS AND METHODS

Totally, 50 patients with metachronous gastric cancer, 50 patients with chronic atrophic gastritis and 50 healthy subjects were collected from October 2015 to October 2018. Patients in the gastric cancer group underwent endoscopic gastrectomy. Serum samples were collected for detection and correlation analysis of serum PG I, PG II, and Hp. In addition, the contents of serum PG and gastrin and postoperative adverse events were statistically analyzed.

RESULTS

There was a statistically significant difference in serum PG I levels, positive Hp infection rate, the number of mast cells, plasma motilin levels and postoperative adverse events among the 3 groups (P<0.01). There was also a significant difference in PG II levels among the groups (P<0.05). On the basis of the results, the amount of inflammatory cells in the gastric cancer group was significantly higher than that in the gastritis group, and there was a remarkable difference in gastric cancer patients before and after operation. Through data analysis, it was found that the levels of PG I and II were the highest in the healthy control group and the lowest in the gastric cancer group, the number of mast cells was the largest in the gastric cancer group, and the level of motilin was the highest in the healthy control group.

CONCLUSION

Hp infection and serum PG levels are associated with metachronous gastric cancer.

Screening, Monitoring, and Treatment of Precancerous Atrophic Gastritis in the Prospective Study for Seven Years

AIM

Develop a program to identify, treat, and prevent severe atrophic gastritis to reduce gastric cancer incidence and mortality.

MATERIALS AND METHODS

In total, 2,847 people aged > 40 years old underwent serological noninvasive screening for atrophic gastritis by identifying postprandial gastrin-17 and pepsinogen-1 in the fasting state. Anti-H pylori IgG was found in 2,134 patients. Seven years later, 2,220 patientswho had undergone serological noninvasive screening were asked to fill out a questionnaire survey (were interviewed). We could not find any information on 627 of 2,847 patients. Next, 75 patients with multifocal atrophic gastritis who underwent gastroscopy and biopsies (the Updated Sydney System (USS)) were selected. To study gastrin-17 production, morpho-functional correlation was studies in 75 patients with multifocal atrophic gastritis.

RESULTS

During seven years, no reported case of gastric cancer was done among 2,220 persons who underwent serological screening and treatment. In the same population, 4.3 persons who did not receive screening during the same period, developed gastric cancer and died of it. In this study, we can say that 4.3 lives were saved out of 2,220 tested persons. The cost for screening this number of people amounted to €23,750. A comparison of the prevalence rate of the four stages of multifocal atrophic gastritis based on the data of the histopathology tests and noninvasive serologic screening in accordance with OLGA classification showed a strong correlation (the correlation coefficient is 0.812). This finding suggested that using this classification not only for histopathology tests for atrophic gastritis but also for serologic markers of antral mucosa and corpus ventriculi atrophy: gastrin-17 and pepsinogen-1.

CONCLUSION

Complex pathogenetic treatment of atrophic gastritis significantly reduced gastric cancer risk and incidence for such patients.<br />.

Serum Pepsinogen as a Predictor for Gastric Cancer Death: A 16-Year Community-based Cohort Study

GOALS

The purpose of this article is to validate the long-term association between initial serum pepsinogen (PG) measurements and subsequent gastric cancer-specific deaths from a long-term longitudinal cohort.

BACKGROUND

Endoscopic surveillance can be effective and efficient in reducing gastric cancer mortality if a biomarker such as serum PG is available to identify high-risk individuals and if the biomarker also is specific to gastric cancer risk.

STUDY

Between 1995 and 1998, a gastric cancer-screening program was conducted in a high-risk population: The first stage involved PG testing, and the second stage involved upper endoscopy. The outcome was gastric cancer death, which was monitored until December 31, 2010; results were expressed as the hazard ratio (HR) and corresponding 95% confidence interval (CI) using the Cox proportional hazards regression model. Other causes of death were used as comparators.

RESULTS

Among participants (n=3514) aged ≥30 years, 1682 (47.9%) were screened to determine serum PG levels. After 16 years of follow-up, 14 deaths from gastric cancer were documented. Multivariate analyses adjusted for age, sex, and Helicobacter pylori serological positivity showed that PG-I <30 μg/L and PG-I <30 μg/L or PG-I/II ratio <3 were significantly associated with the risk of gastric cancer death (HR, 3.27; 95% CI, 1.11-9.61 and HR, 3.45; 95% CI, 1.18-10.12, respectively). In contrast, there were no significant associations between PG and other causes of death, including neoplastic and non-neoplastic diseases.

CONCLUSION

This long-term cohort study shows the usefulness of PG measurement as a biomarker that is specific to the risk of gastric cancer death.

The Value of Pepsinogen in GC Screening: A Systematic Review and Meta-Analysis

Background

The current gold standard for gastric cancer (GC) screening is pathology or a barium meal followed by X-ray. This is not applicable to a wide range of screening capabilities due to the lack of operability. This article used a meta-analysis to evaluate the value of pepsinogen (PG) screening for GC.

Methods

PubMed, EMbase, the Cochrane Library, CNKI, WanFang, VIP, and CBM databases were systematically searched for published studies that used serum PG to diagnose GC. Articles were searched from January 2003 to January 2018. Two reviewers independently screened the literature according to specified inclusion and exclusion criteria. The data were extracted and evaluated, and the quality of the methodologies evaluated using the QUADAS entry. The meta-analysis (MA) was performed using Meta-DiSc 1.4 software. Stata 12.0 software was used to assess publication bias.

Results

A total of 19 studies were finally included from a total of 169,009 cases. The MA showed a combined sensitivity and specificity of 0.56 (95% CI (0.53-0.59), P < 0.01) and 0.71 (95% CI (0.70-0.71), P < 0.01), respectively. The combined likelihood ratios were +LR = 2.82 (95% CI (2.06-3.86), P < 0.01) and -LR = 0.56 (95% CI (0.45-0.68), P < 0.01). The combined DOR was 5.41 (95% CI (3.64~ 8.06), P < 0.01), and the area under the SROC curve was 0.7468.

Conclusions

Serum PG provides medium levels of sensitivity and specificity for GC assessment. To be used in a clinical setting, further high-quality research must be performed and verified.

The potential value of serum pepsinogen for the diagnosis of atrophic gastritis among the health check-up populations in China: a diagnostic clinical research

BACKGROUND

The aim of this study is to assess the validity of the measurement of pepsinogen as a screening test for chronic atrophic gastritis (AG) in health check-up populations in China.

METHODS

Patients from consecutive regular health check-up were enrolled from January 2014 to June 2015. Endoscopy, combined with monitoring the Helicobacter pylori (Hp) infections, and measuring the serum pepsinogen (PG) were used to determine the diagnostic accuracy of PG for the screening of atrophic gastritis. Histopathology was assessed by the Operative Link on Gastritis Assessment (OLGA) system. Statistical analysis was performed using SPSS statistical software.

RESULTS

The total Hp infection rate was 40%. Based on pathology, the 996 participants were divided into three groups: non-atrophic (NAG), mild-moderate atrophic (MAG): stage I and II of the OLGA classification, and severe atrophic (SAG): stage III and IV of the OLGA classification. Compared with NAG and MAG groups, PGR decreased significantly in SAG group (p < 0.05). PGI and PGII levels were significantly elevated in Hp-positive group, while the PGR was markedly decreased (p < 0.01). When MAG and SAG groups were combined and compared with NAG group, the best cutoff value for atrophy diagnosis was PGI ≤50.3 ng/ml; the cutoff value in Hp-negative group was absolutely higher than in Hp-positive group. When NAG and MAG groups were combined and compared with the SAG group, the best cutoff value for diagnosis of severe atrophy was at PGR ≤4.28. The cutoff values in Hp-negative and Hp-positive groups were calculated at PGR ≤6.28 and ≤4.28, respectively.

CONCLUSIONS

Pepsinogens play an important role in the identification of patients with atrophic gastritis and severe AG. Use of different cutoff values of PG for Hp-negative and Hp-positive groups may offer greater efficacy in the diagnosis of AG.

Diagnostic value of serum pepsinogen and anti-Helicobacter pylori IgG levels in patients with peptic ulcer

AIM

To evaluate the diagnostic value of serum pepsinogen (PG) and anti-Helicobacter pylori (H. pylori) immunoglobulin G (IgG) levels in patients with peptic ulcer.

METHODS

Two hundred and fifty patients with peptic ulcer treated at Baodi Clinical College of Medical University of Tianjin from January 2015 to July 2016 were included as an observation group, and 250 healthy volunteers were used as controls. Serum PG levels were determined by chemiluminescence microparticle immuno assay, and anti-H. pylori IgG levels were detected by enzyme linked immunosorbent assay. The diagnostic value of PG and anti-H. pylori levels in peptic ulcer were then analyzed.

RESULTS

Serum pepsinogen Ⅰ(PGⅠ) and pepsinogen Ⅱ (PGⅡ) levels and PGⅠ/ PGⅡ ratio (PGR) were significantly higher in the observation group than in the control group (P < 0.05). Of 50 patients in the observation group, 31 were H. pylori positive and 19 were H. pylori negative. Serum PGⅠ and PGⅡ levels and PGR were significantly higher in H. pylori positive patients than in H. pylori negative ones (P < 0.05). Combined detection of PGⅠ, PGⅡ and PGR had a higher sensitivity and specificity in diagnosing peptic ulcer than in detection any one of the three indexes alone (P < 0.05).

CONCLUSION

Serum PG and anti-H. pylori IgG levels can be used for early screening of peptic ulcer.

Long-term follow-up of pepsinogen I/II ratio after eradication of Helicobacter pylori in patients who underwent endoscopic mucosal resection for gastric cancer

BACKGROUND

Although the pepsinogen I/II (PGI/II) ratio after Helicobacter pylori eradication is recovered at short-term follow-up, long-term follow-up studies of PGI/II are rare.

METHODS

A total of 773 patients with gastric cancer who underwent endoscopic resection and pepsinogen and H. pylori tests were enrolled. H. pylori was eradicated in these patients. Endoscopic and pepsinogen tests were performed every year. A low PGI/II ratio was defined as ≤3.

RESULTS

The PGI/II ratio was higher in non-infected patients (n=275, 4.99) than infected patients (n=498, 3.53). After H. pylori eradication, the PGI/II ratio increased to 5.81 and 5.63 after 1 and 2 years (each p<0.05). The PGI/II ratio in the non-eradication group decreased to 3.94 and 2.75 after 1 and 2 years. The PGI/II ratio in the H. pylori eradication group became similar to that of the H. pylori-negative group at 3 (4.48 vs. 4.34), 4 (4.88 vs. 4.34), and 5 years (4.89 vs. 4.23). The adjusted odds ratios for a lower PG I/II ratio in the non-eradication group compared to the eradication group were 4.78 (95% CI 2.15-10.67) after 1year and 8.13 (95% CI 2.56-25.83) after 2 years.

CONCLUSIONS

After H. pylori eradication, the PGI/II ratio increased and was similar to that of H. pylori-negative controls for up to 5 years of follow-up.

A Serological Biopsy Using Five Stomach-Specific Circulating Biomarkers for Gastric Cancer Risk Assessment: A Multi-Phase Study

OBJECTIVES

We aimed to assess a serological biopsy using five stomach-specific circulating biomarkers-pepsinogen I (PGI), PGII, PGI/II ratio, anti-Helicobacter pylori (H. pylori) antibody, and gastrin-17 (G-17)-for identifying high-risk individuals and predicting risk of developing gastric cancer (GC).

METHODS

Among 12,112 participants with prospective follow-up from an ongoing population-based screening program using both serology and gastroscopy in China, we conducted a multi-phase study involving a cross-sectional analysis, a follow-up analysis, and an integrative risk prediction modeling analysis.

RESULTS

In the cross-sectional analysis, the five biomarkers (especially PGII, the PGI/II ratio, and H. pylori sero-positivity) were associated with the presence of precancerous gastric lesions or GC at enrollment. In the follow-up analysis, low PGI levels and PGI/II ratios were associated with higher risk of developing GC, and both low (<0.5 pmol/l) and high (>4.7 pmol/l) G-17 levels were associated with higher risk of developing GC, suggesting a J-shaped association. In the risk prediction modeling analysis, the five biomarkers combined yielded a C statistic of 0.803 (95% confidence interval (CI)=0.789-0.816) and improved prediction beyond traditional risk factors (C statistic from 0.580 to 0.811, P<0.001) for identifying precancerous lesions at enrollment, and higher serological biopsy scores based on the five biomarkers at enrollment were associated with higher risk of developing GC during follow-up (P for trend <0.001).

CONCLUSIONS

A serological biopsy composed of the five stomach-specific circulating biomarkers could be used to identify high-risk individuals for further diagnostic gastroscopy, and to stratify individuals' risk of developing GC and thus to guide targeted screening and precision prevention.

Combination of Helicobacter pylori Antibody and Serum Pepsinogen as a Good Predictive Tool of Gastric Cancer Incidence: 20-Year Prospective Data From the Hisayama Study

BACKGROUND

There is little information regarding whether the combination of Helicobacter pylori (H. pylori) antibody and serum pepsinogen (sPG), which is a marker of the degree of atrophic gastritis, has a discriminatory ability for detecting incident gastric cancer. We examined this issue in a long-term prospective cohort study of a Japanese population.

METHODS

A total of 2446 Japanese community-dwelling individuals aged ≥40 years were stratified into four groups according to baseline H. pylori serological status and sPG: Group A (H. pylori[-], sPG[-]), Group B (H. pylori[+], sPG[-]), Group C (H. pylori[+], sPG[+]), and Group D (H. pylori[-], sPG[+]), and participants were followed up prospectively for 20 years.

RESULTS

During the follow-up, 123 subjects developed gastric cancer. Compared with that in Group A, the cumulative incidence of gastric cancer was significantly increased in Groups B, C, and D, whereas no significant difference was found between Groups C and D. The multivariable-adjusted risk of gastric cancer was significantly increased in Group B (hazard ratio [HR], 4.08; 95% confidence interval [CI], 1.62-10.28) and in Groups C and D combined (HR 11.1; 95% CI, 4.45-27.46). When the multivariable model with H. pylori antibody was changed into that with the combination of H. pylori antibody and sPG, the C statistics for developing gastric cancer increased significantly (0.773 vs 0.732, P = 0.005), and the continuous net reclassification improvement value was 0.591 (P < 0.001).

CONCLUSIONS

Our findings suggest that the combination of H. pylori antibody and sPG is a useful tool for predicting the development of gastric cancer.

Diagnosis of Helicobacter pylori infection: Current options and developments

Accurate diagnosis of Helicobacter pylori (H. pylori) infection is a crucial part in the effective management of many gastroduodenal diseases. Several invasive and non-invasive diagnostic tests are available for the detection of H. pylori and each test has its usefulness and limitations in different clinical situations. Although none can be considered as a single gold standard in clinical practice, several techniques have been developed to give the more reliable results. Invasive tests are performed via endoscopic biopsy specimens and these tests include histology, culture, rapid urease test as well as molecular methods. Developments of endoscopic equipment also contribute to the real-time diagnosis of H. pylori during endoscopy. Urea breathing test and stool antigen test are most widely used non-invasive tests, whereas serology is useful in screening and epidemiological studies. Molecular methods have been used in variable specimens other than gastric mucosa. More than detection of H. pylori infection, several tests are introduced into the evaluation of virulence factors and antibiotic sensitivity of H. pylori, as well as screening precancerous lesions and gastric cancer. The aim of this article is to review the current options and novel developments of diagnostic tests and their applications in different clinical conditions or for specific purposes.

Gastric adenocarcinoma screening and prevention in the era of new biomarker and endoscopic technologies: a cost-effectiveness analysis

OBJECTIVE

To estimate the cost-effectiveness of noncardia gastric adenocarcinoma (NCGA) screening strategies based on new biomarker and endoscopic technologies.

DESIGN

Using an intestinal-type NCGA microsimulation model, we evaluated the following one-time screening strategies for US men: (1) serum pepsinogen to detect gastric atrophy (with endoscopic follow-up of positive screen results), (2) endoscopic screening to detect dysplasia and asymptomatic cancer (with endoscopic mucosal resection (EMR) treatment for detected lesions) and (3) Helicobacter pylori screening and treatment. Screening performance, treatment effectiveness, cancer and cost data were based on published literature and databases. Subgroups included current, former and never smokers. Outcomes included lifetime cancer risk and incremental cost-effectiveness ratios (ICERs), expressed as cost per quality-adjusted-life-year (QALY) gained.

RESULTS

Screening the general population at age 50 years reduced the lifetime intestinal-type NCGA risk (0.24%) by 26.4% with serum pepsinogen screening, 21.2% with endoscopy and EMR and 0.2% with H. pylori screening/treatment. Targeting current smokers reduced the lifetime risk (0.35%) by 30.8%, 25.5%, and 0.1%, respectively. For all subgroups, serum pepsinogen screening was more effective and more cost-effective than all other strategies, although its ICER varied from $76,000/QALY (current smokers) to $105,400/QALY (general population). Results were sensitive to H. pylori prevalence, screen age and serum pepsinogen test sensitivity. Probabilistic sensitivity analysis found that at a $100,000/QALY willingness-to-pay threshold, the probability that serum pepsinogen screening was preferred was 0.97 for current smokers.

CONCLUSIONS

Although not warranted for the general population, targeting high-risk smokers for serum pepsinogen screening may be a cost-effective strategy to reduce intestinal-type NCGA mortality.

Significance of Serum Pepsinogens as a Biomarker for Gastric Cancer and Atrophic Gastritis Screening: A Systematic Review and Meta-Analysis

BACKGROUND

Human pepsinogens are considered promising serological biomarkers for the screening of atrophic gastritis (AG) and gastric cancer (GC). However, there has been controversy in the literature with respect to the validity of serum pepsinogen (SPG) for the detection of GC and AG. Consequently, we conducted a systematic review and meta-analysis to assess the diagnostic accuracy of SPG in GC and AG detection.

METHODS

We searched PubMed, Embase, and the Chinese National Knowledge Infrastructure (CNKI) for correlative original studies published up to September 30, 2014. The summary sensitivity, specificity, positive diagnostic likelihood ratio (DLR+), negative diagnostic likelihood ratio (DLR-), area under the summary receiver operating characteristic curve (AUC) and diagnostic odds ratio (DOR) were used to evaluate SPG in GC and AG screening based on bivariate random effects models. The inter-study heterogeneity was evaluated by the I2 statistics and publication bias was assessed using Begg and Mazumdar's test. Meta-regression and subgroup analyses were performed to explore study heterogeneity.

RESULTS

In total, 31 studies involving 1,520 GC patients and 2,265 AG patients were included in the meta-analysis. The summary sensitivity, specificity, DLR+, DLR-, AUC and DOR for GC screening using SPG were 0.69 (95% CI: 0.60-0.76), 0.73 (95% CI: 0.62-0.82), 2.57 (95% CI: 1.82-3.62), and 0.43 (95% CI: 0.34-0.54), 0.76 (95% CI: 0.72-0.80) and 6.01 (95% CI: 3.69-9.79), respectively. For AG screening, the summary sensitivity, specificity, DLR+, DLR-, AUC and DOR were 0.69 (95% CI: 0.55-0.80), 0.88 (95% CI: 0.77-0.94), 5.80 (95% CI: 3.06-10.99), and 0.35 (95% CI: 0.24-0.51), 0.85 (95% CI: 0.82-0.88) and 16.50 (95% CI: 8.18-33.28), respectively. In subgroup analysis, the use of combination of concentration of PGI and the ratio of PGI:PGII as measurement of SPG for GC screening yielded sensitivity of 0.70 (95% CI: 0.66-0.75), specificity of 0.79 (95% CI: 0.79-0.80), DOR of 6.92 (95% CI: 4.36-11.00), and AUC of 0.78 (95% CI: 0.72-0.81), while the use of concentration of PGI yielded sensitivity of 0.55 (95% CI: 0.51-0.60), specificity of 0.79 (95% CI: 0.76-0.82), DOR of 6.88 (95% CI: 2.30-20.60), and AUC of 0.77 (95% CI: 0.73-0.92). For AG screening, the use of ratio of PGI:PGII as measurement of SPG yielded sensitivity of 0.69 (95% CI: 0.52-0.83), specificity of 0.84 (95% CI: 0.68-0.93), DOR of 11.51 (95% CI: 6.14-21.56), and AUC of 0.83 (95% CI: 0.80-0.86), the use of combination of concentration of PGI and the ratio of PGI:PGII yield sensitivity of 0.79 (95% CI: 0.72-0.85), specificity of 0.89 (95% CI: 0.85-0.93), DOR of 24.64 (95% CI: 6.95-87.37), and AUC of 0.87 (95% CI: 0.81-0.92), concurrently, the use of concentration of PGI yield sensitivity of 0.46 (95% CI: 0.38-0.54), specificity of 0.93 (95% CI: 0.91-0.95), DOR of 19.86 (95% CI: 0.86-456.91), and AUC of 0.86 (95% CI: 0.52-1.00).

CONCLUSION

SPG has great potential as a noninvasive, population-based screening tool in GC and AG screening. In addition, given the potential publication bias and high heterogeneity of the included studies, further high quality studies are required in the future.

Diagnosis of Helicobacter pylori infection: Current options and developments

Accurate diagnosis of Helicobacter pylori (H. pylori) infection is a crucial part in the effective management of many gastroduodenal diseases. Several invasive and non-invasive diagnostic tests are available for the detection of H. pylori and each test has its usefulness and limitations in different clinical situations. Although none can be considered as a single gold standard in clinical practice, several techniques have been developed to give the more reliable results. Invasive tests are performed via endoscopic biopsy specimens and these tests include histology, culture, rapid urease test as well as molecular methods. Developments of endoscopic equipment also contribute to the real-time diagnosis of H. pylori during endoscopy. Urea breathing test and stool antigen test are most widely used non-invasive tests, whereas serology is useful in screening and epidemiological studies. Molecular methods have been used in variable specimens other than gastric mucosa. More than detection of H. pylori infection, several tests are introduced into the evaluation of virulence factors and antibiotic sensitivity of H. pylori, as well as screening precancerous lesions and gastric cancer. The aim of this article is to review the current options and novel developments of diagnostic tests and their applications in different clinical conditions or for specific purposes.

Diagnostic values of serum levels of pepsinogens and gastrin-17 for screening gastritis and gastric cancer in a high risk area in northern Iran

BACKGROUND

Gastric cancer (GC) is the second cause of cancer related death in the world. It may develop by progression from its precancerous condition, called gastric atrophy (GA) due to gastritis. The aim of this study was to evaluate the accuracy of serum levels of pepsinogens (Pg) and gastrin-17 (G17) as non-invasive methods to discriminate GA or GC (GA/GC) patients.

MATERIALS AND METHODS

Subjects referred to gastrointestinal clinics of Golestan province of Iran during 2010 and 2011 were invited to participate. Serum levels of PgI, PgII and G17 were measured using a GastroPanel kit. Based on the pathological examination of endoscopic biopsy samples, subjects were classified into four groups: normal, non-atrophic gastritis, GA, and GC. Receiver operating curve (ROC) analysis was used to determine cut-off values. Indices of validity were calculated for serum markers.

RESULTS

Study groups were normal individuals (n=74), non-atrophic gastritis (n=90), GA (n=31) and GC patients (n=30). The best cut-off points for PgI, PgI/II ratio, G17 and HP were 80 μg/L, 10, 6 pmol/L, and 20 EIU, respectively. PgI could differentiate GA/GC with high accuracy (AUC=0.83; 95%CI: 0.76-0.89). The accuracy of a combination of PgI and PgI/II ratio for detecting GA/GC was also relatively high (AUC=0.78; 95%CI: 0.70-0.86).

CONCLUSIONS

Our findings suggested PgI alone as well as a combination of PgI and PgI/II ratio are valid markers to differentiate GA/GC. Therefore, Pgs may be considered in conducting GC screening programs in high-risk areas.

Short term micronutrient-antioxidant supplementation has no impact on a serological marker of gastric atrophy in Zambian adults: retrospective analysis of a randomised controlled trial

BACKGROUND

Gastric cancer is a major contributor to cancer deaths in Zambia but, as elsewhere, no preventive strategies have been identified. We set out to investigate the possibility of reducing gastric atrophy, a premalignant lesion, using micronutrient-antioxidant supplementation.

METHODS

We analysed 215 archival samples from a randomised controlled trial of micronutrient-antioxidant supplementation carried out from 2003 to 2006. Participants were randomised to receive either the supplement or placebo and had been taking the allocated intervention for a mean of 18 (range 14-27) months when the samples used in this study were taken. We used low pepsinogen 1 to 2 (PEP1:2) ratio as a surrogate marker of gastric atrophy. A PEP 1:2 ratio of less than three was considered low. HIV serology, age, nutritional status, smoking, alcohol intake and gastric pH were also analysed. Ethical approval was obtained from the University of Zambia Biomedical Research Ethics Committee (011-04-12). The randomized trial was registered (ISRCTN31173864).

RESULTS

The overall prevalence of low PEP 1:2 ratio was 15/215 (7%) and it did not differ between the placebo (8/103, 7.8%) and micronutrient groups (7/112, 6.3%; HR 1.24; 95% CI 0.47-3.3; P = 0.79). The presence of low PEP 1:2 ratio was not influenced by HIV infection (HR 1.07; 95% CI 0.37-3.2; P =0.89) or nutritional status but it inversely correlated with gastric pH (Spearman's rho = -0.34; P = 0.0001). Age above 40 years was associated with atrophy, but neither alcohol nor smoking had any influence.

CONCLUSION

Short term micronutrient supplementation does not have any impact on PEP 1:2 ratio, a serological marker of gastric atrophy. PEP 1:2 ratio inversely correlates with gastric pH.

Coffee intake and gastric cancer risk: the Singapore Chinese health study

BACKGROUND

Despite experimental evidence showing chemopreventive effects of coffee-related compounds on gastric carcinogenesis, epidemiologic studies generally do not support coffee-gastric cancer associations. Observational data are lacking among high-risk populations with sufficient regular coffee consumption.

METHODS

We examined the association between caffeinated coffee intake and gastric cancer risk in a population-based cohort that enrolled 63,257 Chinese men and women ages 45 to 74 years between 1993 and 1998 in Singapore. Incident gastric cancer cases (n = 647) were identified after a mean follow-up of 14.7 years. Biomarkers of Helicobacter pylori (H. pylori) infection were measured in a subset of gastric cancer cases with blood collected before cancer diagnosis and their matched controls.

RESULTS

In the total cohort, daily versus nondaily coffee intake was associated with a statistically nonsignificant decrease in gastric cancer risk [HR = 0.85; 95% confidence interval (CI), 0.69-1.04]. In women, the inverse association strengthened and reached statistical significance (HR = 0.63; 95% CI, 0.46-0.87). In analyses restricted to never smokers and nondrinkers of alcohol, inverse associations strengthened in the total cohort (HR = 0.69; 95% CI, 0.52-0.91) and in women (HR = 0.52; 95% CI, 0.37-0.74). There was no coffee-gastric cancer risk association among men, regardless of smoking status or alcohol consumption. Similar results were observed in the nested case-control study after adjustment for H. pylori infection.

CONCLUSION

Daily coffee consumption may reduce the risk of gastric cancer in high-risk populations, especially among women.

IMPACT

Research aimed at identifying the compounds in coffee that may protect against gastric carcinogenesis is warranted.

Diagnosis and epidemiology of Helicobacter pylori infection

A limited amount of new information was published in the field of diagnosis and epidemiology of Helicobacter pylori this last year. Besides some improvement in current tests, it is interesting to note the attempts to identify severe disease, for example gastric cancer, by breath analysis using nanomaterial-based sensors. In contrast, the predictive value for gastric cancer and atrophy of pepsinogen determinations was found inadequate. Prevalence studies of H. pylori infection have been carried out in adults and children around the world in the general population but also in specific communities. The usual risk factors were found. In addition, a Japanese study highlighted the role of grandmothers in the familial transmission of H. pylori. A study showed that the infection may not always readily establish itself in children, given the number of transient infections observed. It was also noted that after eradication, a first-year relapse is likely to be a recurrence of the previous infection, while later on it is probably a reinfection with a new strain.

Serum pepsinogen II is a better diagnostic marker in gastric cancer

AIM

To investigate screening makers for gastric cancer, we assessed the association between gastric cancer and serum pepsinogens (PGs).

METHODS

The subjects comprised 450 patients with gastric cancer, 111 individuals with gastric atrophy, and 961 healthy controls. Serum anti-Helicobacter pylori (H. pylori) immunoglobulin G (IgG), PGI and PG II were detected by enzyme-linked immunosorbent assay. Gastric atrophy and gastric cancer were diagnosed by endoscopy and histopathological examinations. Odds ratios and 95%CIs were calculated using multivariate logistic regression.

RESULTS

Rates of H. pylori infection remained high in Northeastern China. Rates of H. pylori IgG positivity were greater in the gastric cancer and gastric atrophy groups compared to the control group (69.1% and 75.7% vs 49.7%, P < 0.001). Higher levels of PG II (15.9 μg/L and 13.9 μg/L vs 11.5 μg/L, P < 0.001) and lower PGI/PG II ratio (5.4 and 4.6 vs 8.4, P < 0.001) were found in patients with gastric cancer or gastric atrophy compared to healthy controls, whereas no correlation was found between the plasma PGI concentration and risk of gastric cancer (P = 0.537). In addition, multivariate logistic analysis indicated that H. pylori infection and atrophic gastritis were independent risk factors for gastric cancer. Lower plasma PGI/PG II ratio was associated with higher risks of atrophy and gastric cancer. Furthermore, plasma PG II level significantly correlated with H. pylori-infected gastric cancer.

CONCLUSION

Serum PG II concentration and PGI/PG II ratio are potential biomarkers for H. pylori-infected gastric disease. PG II is independently associated with risk of gastric cancer.

Helicobacter pylori: clinical management

PURPOSE OF REVIEW

Progress continues in our understanding of the role of Helicobacter pylori infection in gastroduodenal as well as extragastric disorders. This review gives an overview on selected areas of the H. pylori infection and their clinical implications.

RECENT FINDINGS

Indications for therapy have been extended and now include idiopathic thrombocytopenic purpura, iron deficiency anemia, and vitamin B12 deficiency. New data are presented on the role of H. pylori in neurodegenerative disorders and in the metabolic syndrome. H. pylori is associated with a (small) increase in the risk for colorectal adenoma and colon cancer. The biggest challenge is the selection of new therapies and treatment strategies because of the increasing failure of standard triple therapies. The best option in high clarithromycin resistance areas is bismuth-based quadruple therapy. Probiotic bacteria and yeasts reduce adverse effects of standard H. pylori eradication regimens. In gastric cancer prevention, screening programs based on the serological detection of preneoplastic conditions may prove useful.

SUMMARY

New algorithms for preventing H. pylori-induced disease and eradicating the organism should be individualized.

Helicobacter pylori: gastric cancer and extragastric intestinal malignancies

The greatest challenge in Helicobacter pylori-related diseases continues to remain prevention of gastric cancer. New evidence supports the beneficial effect of H. pylori eradication not only on prevention of gastric cancer but also on the regression of preneoplastic conditions of the gastric mucosa. Concerning early detection of gastric cancer there are still no adequate means and there is urgent need to define appropriate markers, for example, by genome-wide research approaches. Currently, the best available method is the "serologic" biopsy based on pepsinogen I and the pepsinogen I/II ratio for identification of patients with severe gastric atrophy at increased risk for gastric cancer development. The treatment of early gastric cancer by endoscopic techniques can be performed safely and efficiently, but patients need meticulous follow-up for detection of metachronous lesions. In case of advanced disease, laparoscopically assisted surgical procedures are safe and favorable compared to open surgery. Two phase III trials support the role of adjuvant systemic treatment with different regimens. Unfortunately, there is still only slow progress in the development of palliative treatment regimens or modification of the existing therapy protocols. There is accumulating evidence for a role of H. pylori infection also in colorectal carcinogenesis. Seropositive individuals are at higher risk for the development of colorectal adenomas and consequently adenocarcinomas of this anatomical region. This phenomenon can partly be attributed to the increase of serum gastrin as response to atrophic changes of the gastric mucosa.