Overdiagnosis of gastric cancer by endoscopic screening

Burden of gastrointestinal cancers in China from 1990 to 2019 and projection through 2029

Although gastrointestinal (GI) cancers pose a great challenge to public health, data are scant for understanding the burden of GI cancers in China. We aimed to provide an updated estimate of the burden of major GI cancers in China over three decades. According to the GLOBOCAN 2020 database, 1,922,362 GI cancer cases were newly diagnosed and 1,497,388 deaths occurred in China in 2020, with the highest incidence in colorectal cancer (555,480 new cases; 23.90/100,000 age-standardized incidence rate [ASIR]) and the highest mortality in liver cancer (391,150 deaths; 17.20/100,000 age-standardized mortality rate [ASMR]). The age-standardized rates (ASRs) in incidence, mortality, and disability-adjusted life year (DALY) rates for esophageal, gastric, and liver cancers have declined overall (1990-2019, average annual perventage change [AAPC] < 0%, p < 0.001) but have become flattened or reversed in recent years, alarmingly. The spectrum of GI cancers in China will continue transitioning in the next decade, characterized by rapid increases in colorectal and pancreatic cancers in addition to a high burden of esophageal, gastric, and liver cancers. High body-mass index was found to be the fastest-growing risk factor for GI cancers (estimated annual perventage change [EAPC]: 2.35%-3.20%, all p < 0.001), whereas smoking and alcohol consumption remained the top contributors to GI cancer-related deaths in men. In conclusion, GI cancers in China are challenging the healthcare system with a growing burden and a transitioning pattern. Comprehensive strategies are needed to reach the Healthy China 2030 target.

Identification of serum microRNAs as potential diagnostic biomarkers for detecting precancerous lesions of gastric cancer

Aim

Gastric mucosal changes associated with chronic gastritis are known to be precancerous lesions of gastric cancer. We aimed to identify individuals with a high risk of gastric cancer by detection of microRNAs (miRNA) in the blood as biomarkers.

Methods

Of 1206 individuals screened, 144 who were positive for Helicobacter pylori (H. pylori) by the serum antibody test and who underwent endoscopy were the subjects of this study. For the gross assessment of mucosal inflammation, we applied the Kimura-Takemoto classification, in which normal mucosa was defined as grade 0, and atrophy was categorized as grade 1 (C-1 and C-2), grade 2 (C-3 and O-1), and grade 3 (O-2 and O-3). Serum samples were divided into two phases and used for miRNA microarray profiling. We compared the expression of miRNAs in grade 3 mucosa and other grades. Expression in gastric cancer was confirmed with TCGA data.

Results

miR-196b-3p was significantly upregulated, and miR-92a-2-5p was downregulated (P < .05 and q < 0.2). TCGA data showed a high expression of miR-196b-3p in gastric cancer cases (P < .001). Comparing grade 3 and the others, the area under the receiver operating characteristic curve using the detected miRNAs was as high as about 0.7. Furthermore, the combination of miRNAs resulted in higher accuracy. In terms of the significance of the combinatory mRNAs, the combination of three miRNAs (miR-196b-3p, miR-92a-2-5p, and miR-6791-3p) revealed high sensitivity and specificity, with the area under the curve exceeding 0.8.

Conclusion

The identified combinatory miRNAs may represent promising biomarkers of precancerous lesions in gastric cancer.

Gastric Cancer Screening in Japan: A Narrative Review

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

Scoring model for discriminating gastric cancer risk in patients with negative serum pepsinogen and anti-Helicobacter pylori antibody results

BACKGROUND

The ABC test measures serum pepsinogen and anti-Helicobacter pylori IgG antibody levels to predict precancerous conditions in the stomach and gastric cancer. However, a limitation of this test is that the gastric cancer risk is not negligible in patients with a negative result.

METHODS

Based on their ABC results, 1157 patients were classified into Groups A (n = 392), B (n = 479), C (n = 247), and D (n = 39). In Group A, 24.2% of patients had atrophic gastritis and/or intestinal metaplasia and had thus been incorrectly assigned to Group A. Patients in Group A were then assigned to derivation (n = 236) and validation (n = 156) cohorts by 3:2 random sampling. Logistic regression analyses were performed to identify the factors discriminating between a correct (true) and incorrect (false) Group A classification.

RESULTS

A 4-point discriminative model was constructed based on a high-negative H. pylori IgG antibody titer and the patient's age (50-64 and ≥65 years). The areas under the receiver operating characteristic curve for the derivation and validation cohorts were 0.868 and 0.894, respectively. In the validation cohort, the addition of a discriminative model score ≥2 to the ABC method showed a similar accuracy for predicting gastric cancer risk compared with the ABC method alone (93.8% vs. 92.4%).

CONCLUSION

The 4-point discriminative model may help identify patients with a normal serological test who are nonetheless at risk of developing gastric cancer.

Breath volatile organic compound analysis: an emerging method for gastric cancer detection

Gastric cancer is a common malignancy, being the fifth most frequently diagnosed cancer and the fourth leading cause of cancer-related deaths worldwide. Diagnosis of gastric cancer at the early stage is critical to effectively improve the survival rate. However, a substantial proportion of patients with gastric cancer in the early stages lack specific symptoms or are asymptomatic. Moreover, the imaging techniques currently used for gastric cancer screening, such as computed tomography and barium examination, are usually radioactive and have low sensitivity and specificity. Even though endoscopy has high accuracy for gastric cancer screening, its application is limited by the invasiveness of the technique. Breath analysis is an economic, effective, easy to perform, non-invasive detection method, and has no undesirable side effects on subjects. Extensive worldwide research has been conducted on breath volatile organic compounds (VOCs), which reveals its prospect as a potential method for gastric cancer detection. Many interesting results have been obtained and innovative methods have been introduced in this subject; hence, an extensive review would be beneficial. By providing a comprehensive list of breath VOCs identified by gastric cancer would promote further research in this field. This review summarizes the commonly used technologies for exhaled breath analysis, focusing on the application of analytical instruments in the detection of breath VOCs in gastric cancers, and the alterations in the profile of breath biomarkers in gastric cancer patients are discussed as well.

A study protocol for expanding the screening interval of endoscopic screening for gastric cancer based on individual risks: prospective cohort study of gastric cancer screening

Background

The Japanese government has recommended a 2-year endoscopic screening interval for gastric cancer. However, insufficient resources have constrained participation in endoscopic screening for gastric cancer. One way to avoid endoscopic screening harms and provide equal access is to define the appropriate screening interval.

Methods

To expand screening interval from more than 2 years for low-risk group, a single-arm cohort of endoscopic screening started. At the baseline screening, the participants underwent endoscopic screening for gastric cancer, Helicobacter pylori (H. pylori) antibody test, and serum pepsinogen test (first year), and followed after 2 and 4 years (within the first 5 years). We also assessed H. pylori infection and atrophy status on images of upper gastrointestinal endoscopy at the baseline. A new screening model will be developed by dividing the participants into high-risk and low-risk groups based on demographics, history of H. pylori eradication, serological testing, and endoscopic diagnosis. The cumulative gastric cancer incidence after negative results at baseline are compared between the low-risk group on the 3rd screening round after 4 years from baseline and the total screening group on the 2nd screening round after 2 years. If the cumulative gastric cancer incidence in the low-risk group on the 3rd screening round is lower than that in the total screening group on the 2nd screening round, the screening interval can be expanded to 4 years in the low-risk group.

Discussion

To reduce mortality from gastric cancer, a high participation rate of the target population is required. The screening interval of endoscopic screening can be changed if the individual risks for H. pylori infection are clarified. Our goal in this study is to obtain relevant data that can be used to improve the efficient use of endoscopic screening for gastric cancer by referring to individual risks in Japan.

Trial registration

UMIN000025839 (University Hospital Medical Information Network, Japan)

The Clinicopathological Features and Staging at Presentation of Gastric Cancer: A Single-Center Retrospective Study

Introduction Gastric cancer (GC) is the third leading cause of cancer death, with most patients diagnosed at a later stage, with distant metastasis at the time of presentation, contributing to poor prognosis. GC has been associated with nonspecific clinical presentations, which cause a time delay for patients to seek for medical advice. This study aims to identify the clinicopathological features of GC patients and correlate time delay of the diagnosis to the staging of the disease.

Materials and Methods This is a single-center retrospective study of GC patients diagnosed from January 2012 to December 2018. All relevant data of GC patient diagnosed during this time period were extracted from the patients’ case notes.

Results A total of 69 GC patients were included in this study, with male preponderance and mean age of 62 years old. The top three symptoms presented are dyspepsia or ingestion (47.8%), weight loss (43.5%), and nausea or vomiting (33.3%). The mean time delay was 3.7 months. Patients presented with weight loss have a significantly longer average time delay of 4.88 months. Most tumor lesion was found at the distal stomach (43.5%), while 74.5% tested negative for Helicobacter pylori. Most patients were diagnosed at Stage IV (52.6%) and Stage III (36.8%) of the disease, with poorly differentiated (67.7%) histological features which have poor prognosis.

Discussion and Conclusion No evidence of specific symptom or combination of symptoms predicts higher risk of GC. Regardless of the number of symptoms presented or the time delay, most GC patients were diagnosed at later stage of the disease. The study shows the importance of GC screening in Malaysia to ensure early detection, even before a symptom presented.

The diagnostic value of serum gastrokine 1 (GKN1) protein in gastric cancer

Early detection of cancer provides effective treatment and saves lives. The objective of this study was to determine whether serum gastrokine 1 (GKN1) protein is a gastric cancer‐specific diagnostic biomarker. The serum concentration of GKN1 in healthy individuals (median: 6.34 ng/μL, interquartile range (IQR): 5.66‐7.54 ng/μL) was significantly higher compared with the levels in gastric cancer patients (median: 3.48 ng/μL, IQR: 2.90‐4.11 ng/μL; P < .0001). At the optimum cutoff (4.94 ng/μL) of serum GKN1 protein, the sensitivity and specificity were 91.2% and 96.0%, respectively, for gastric cancer. Using serum GKN1 protein as the diagnostic reference, the ROC curve showed a satisfactory diagnostic efficacy with an AUC value of 0.9954 (95% CI 0.9919‐0.9988) and Youden index of 0.8740. In addition, the diagnostic accuracy of the serum GKN1 protein at the optimum cutoff was 0.9675. Interestingly, serum GKN1 concentrations in patients with advanced gastric cancer (AGC; median: 3.11 ng/μL, IQR: 2.72‐3.72 ng/μL) were lower than in patients with early gastric cancer (EGC; median: 4.31 ng/μL, IQR: 3.88‐4.88 ng/μL). The diagnostic accuracies at the optimum serum GKN1 cutoff were 0.8912 and 0.9589 for EGC and AGC, respectively. Furthermore, the serum GKN1 concentrations robustly discriminated the patients with gastric cancer from the patients with colorectal, liver, lung, breast, pancreatic, ovary, and prostatic cancers with AUC values greater than 0.94. These data suggest that serum GKN1 is a promising and highly specific diagnostic biomarker for the prompt detection of early and advanced gastric cancers.

Gastric cancer in patients with gastric atrophy and intestinal metaplasia: A systematic review and meta-analysis

AIM

Intestinal metaplasia (IM) and gastric atrophy (GA) are precancerous lesions in the stomach. There is a large debate on natural course of these lesions and surveillance strategy in these patients. This meta-analysis was aimed to find the most appropriate follow up and the rate of progression from IM and GA to GC.

METHODS

This meta-analysis is followed and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Electronic databases including EMBASE, PubMed, Web of Science databases, Scopus, and the Cochrane Library were searched until July 2018. Cochran's Q test and I-square (I2) test were used to examine heterogeneity across included studies. We pooled data using random-effect or fixed effect models indicated as incidence rate or proportion with 95% confidence intervals (CI). The variables of study included demographic data, endoscopy interval, follow up interval and time, GA and IM type and GC stage. Moreover, incidence rate of GC and progress rate, regress and persistence proportion in both GA and IM patients were assessed.

RESULTS

Overall, 68 original articles out of 32981 citations were included in our meta-analysis. The pooled GC incidence rate in patients with GA was 1.24 (95% CI, 0.80, 1.76; I2: 83.6%) cases per 1,000 person-years. The rates of later diagnosis of IM and gastric dysplasia in patients with GA were estimated as 41.42 (95% CI, 3.11, 64.45; I2: 95.6%) and 6.23 (95% CI, 2.34, 11.46; I2: 83.0%) cases per 1,000 person-years, respectively. The pooled regressed proportion was 32.23 (95% CI, 18.07-48.02; I2: 94.0%) and the persistence proportion was 38.83 (95% CI, 20.20-59.13; I2: 97.0%) per 100 observations in GA patients. In IM studies, the pooled incidence rate of GC was 3.38 (95% CI, 2.13, 4.85; I2: 93.4%) cases per 1,000 person-years. The progressed rate to dysplasia in IM patient was estimated to be 12.51 (95% CI, 5.45, 22.03; I2: 95.1%) cases per 1,000 person-years. The pooled regressed proportion was 31.83 (95% CI, 25.48-38.51; I2: 91.0%) and the persistence proportion was 43.46 (95% CI, 32.52-54.71; I2: 96.0%) per 100 observations in IM patients.

CONCLUSION

Overall, the incidence of GC in patients with IM and GA are low but there is heterogeneity in data with the highest rate in Asian, males with those with incomplete IM. There is probability of regression or persistence without progression in patients with IM and GA who receive appropriate management.

Preliminary study of magnetically controlled capsule gastroscopy for diagnosing superficial gastric neoplasia

BACKGROUND

Magnetically controlled capsule gastroscopy (MCCG) is a newly developed non-invasive method designed for gastric examination. Although favorable diagnostic accuracy has been reported, there is little if any data about its ability to diagnose gastric cancer.

AIMS

To compare the detectability of superficial gastric neoplasia by MCCG and gastroscopy.

METHODS

This study was a self-controlled comparison study. Ten subjects diagnosed with superficial gastric neoplasia and scheduled to undergo endoscopic submucosal dissection (ESD) at a tertiary hospital were prospectively invited for an MCCG examination. The diagnostic agreement of MCCG, ESD and pathology were compared, including location, size and endoscopic appearance of the lesions.

RESULTS

Of the 10 enrolled patients, 6 were confirmed as having early gastric cancer/high-grade intraepithelial neoplasia, 2 gastric low-grade intraepithelial neoplasia (LGIN), 1 tubular adenoma with LGIN and 1 neuroendocrine tumor. The per-patient and per-lesion sensitivities of MCCG for superficial gastric neoplasia detection were 100% and 91.7%. Location and size of the lesions were compared favorably to gastroscopy whilst one cardiac lesion was missed. Endoscopic appearances of these lesions observed on MCCG and EGD demonstrated good consistency. No adverse events were observed.

CONCLUSION

With good gastric preparation and careful examination of stomach, MCCG is able to detect superficial gastric neoplasms.

Screening for gastric cancer with magnetically controlled capsule gastroscopy in asymptomatic individuals

BACKGROUND AND AIMS

Gastric cancer (GC) is the fourth most common cancer and the fourth leading cause of cancer death worldwide. In some Asian countries, screening EGD has greatly improved the survival rate. However, patients' discomfort and the need for sedation may limit adherence to screening programs. Previous studies have shown good tolerance and good agreement of magnetically controlled capsule gastroscopy (MCCG) with EGD. This study was designed to assess the application of MCCG in GC detection in an asymptomatic population.

METHODS

In this observational cohort study, 3182 asymptomatic individuals undergoing MCCG in 99 participating medical examination centers from April to December 2016 were enrolled. Patients with ulcers and suspected malignancies were referred for gastroscopy and biopsy. The detection rate of GC and focal lesions were used to explore the application of MCCG in asymptomatic individuals.

RESULTS

Seven patients (0.22%) were diagnosed with GC among the enrolled 3182 individuals, accounting for 0.74% (7/948) in patients over 50 years. No gender disparity was observed. EGD and biopsy confirmed adenocarcinoma in all cases of suspected malignancy. Benign polyps, gastric ulcers, and submucosal tumors were found in 10.4%, 4.9%, and 3.6% of patients, respectively. There was a trend for the prevalence of focal lesions to increase with age. MCCG examination proved to be safe.

CONCLUSIONS

MCCG can detect cancer and benign lesions and is safe and clinically feasible in a large population. Studies of its role in a screening program should be considered.

Update version of the Japanese Guidelines for Gastric Cancer Screening

Background

Although the incidence and mortality of gastric cancer have gradually decreased, its burden remains in East Asian countries. Gastric cancer screening has been performed in Japan since 1983, and the introduction of new screening techniques has been eagerly anticipated.

Objective

To promote evidence-based screening, the Japanese guidelines for gastric cancer screening have been revised based on the new studies.

Methods

The guidelines for gastric cancer screening have been developed according to a previously established method. To assess evidence regarding the effectiveness of the screening methods, a systematic review was conducted based on an analytic framework including clinical questions aiming at reducing mortality from gastric cancer. The following methods were assessed for gastric cancer screening: upper gastrointestinal series (radiographic screening), gastrointestinal endoscopy (endoscopic screening), Helicobacter pylori antibody test and serum pepsinogen tests. Based on the balance of the benefits and harms of each screening method, recommendations for population-based and opportunistic screenings were formulated.

Findings

After the Japanese guidelines for gastric cancer screening were published in 2005, several observational studies on radiographic and endoscopic screenings have been reported. Three case-control studies have evaluated mortality reduction from gastric cancer by endoscopic screening. Notably, evidence of the H. pylori antibody and serum pepsinogen tests was insufficient. Although false-positive results, false-negative results, and complications were observed in endoscopic and radiographic screenings, the complication rates were higher in endoscopic screening than in radiographic screening. Overdiagnosis was not estimated directly in both methods.

Recommendations

Radiographic and endoscopic screenings for gastric cancer are recommended for population-based and opportunistic screenings. The H. pylori antibody and serum pepsinogen tests are not recommended for population-based screening because of insufficient evidence.