Follow-up of intestinal metaplasia in the stomach: When, how and why

Risk factors for gastric intestinal metaplasia

Gastric intestinal metaplasia is the most common precancerous lesion of gastric cancer. Due to the unsatisfying treatment efficacy for gastric cancer especially advanced gastric cancer, the key steps of prevention and treatment of gastric cancer are lowering the incidence and improving the early diagnosis. Therefore, it is very important to clarify the risk factors associated with gastric cancer and its precancerous lesion for first-line prevention of gastric cancer. Accumulated evidence indicates that the development of gastric intestinal metaplasia is closely related to Helicobacter pylori infection, age, sex, family history of gastric cancer, smoking, high salt diet, bile acid reflux and so on. This review mainly focuses these factors associated with gastric intestinal metaplasia.

Early detection of colonic dysplasia by magnetic resonance molecular imaging with a contrast agent raised against the colon cancer marker MUC5AC

Human gastric mucin MUC5AC is secreted in the colonic mucus of cancer patients and is a specific marker of precancerous lesions called aberrant crypt foci. Using MUC5AC as a specific marker can improve sensitivity in the detection of early colorectal cancer. Here we demonstrated that the accumulation of MUC5AC in xenograft and mouse stomach can be detected by magnetic resonance imaging (MRI). We used ultrasmall particles of iron oxide (USPIOs) conjugated with disulfide constrained heptapeptide that were identified using a screening phage display. To accomplish this, we employed positive selection of the phage display library on MUC5AC purified from fresh human colonic adenomas in combination with negative selection of the phage library on purified human MUC2, which is predominantly found in normal colorectal tissues. This conjugate was tested on human colorectal cancer cell lines that were either able or unable to secrete MUC5AC, both in vitro and in vivo. MUC5AC-USPIO contrast agent and USPIOs alone were not detected in cell lines unable to secrete MUC5AC. A combination of MRI and microscopy studies was performed to detect a specific accumulation of the contrast agent in vivo. Thus, the MUC5AC contrast agent enabled non-invasive detection of precancerous lesions and colorectal cancer, highlighting its potential use in diagnostics, in the early detection of colorectal cancer recurrences after treatment and in mechanistic studies implicating MUC5AC. Copyright © 2016 John Wiley & Sons, Ltd.

The Prevalence of Gastric Intestinal Metaplasia and Distribution of Helicobacter pylori Infection, Atrophy, Dysplasia, and Cancer in Its Subtypes

Objectives. Gastric intestinal metaplasia (IM) is frequently encountered and is considered a precursor of gastric adenocarcinoma. In the Van region of Turkey, gastric adenocarcinoma incidence is high but the prevalence of gastric IM is not known. Helicobacter pylori (H. pylori) infection is a main factor leading to atrophy, IM, and cancer development in the stomach. The aim of the current study was to investigate the prevalence of IM and its subtypes and the prevalence of H. pylori infection, atrophy, dysplasia, and cancer in gastric IM subtypes. Materials and Methods. This retrospective study was conducted on 560 IM among the 4050 consecutive patients who were undergoing esophagogastroduodenoscopy (EGD) with biopsy between June 2010 and October 2014. Clinical records and endoscopic and histopathologic reports of patients with IM were analyzed. Results. The prevalence of gastric IM was 13.8%. The prevalence of incomplete IM was statistically significantly higher than complete IM. Type III IM was the most frequent subtype. Conclusions. Gastric IM is a common finding in patients undergoing EGD with biopsy in this region. High prevalence of incomplete type IM, especially type III, can be associated with the high prevalence of gastric cancer in our region.

Diagnosis and management of high risk group for gastric cancer

Gastric cancer is associated with high morbidity and mortality worldwide. To reduce the socioeconomic burden related to gastric cancer, it is very important to identify and manage high risk group for gastric cancer. In this review, we describe the general risk factors for gastric cancer and define high risk group for gastric cancer. We discuss strategies for the effective management of patients for the prevention and early detection of gastric cancer. Atrophic gastritis (AG) and intestinal metaplasia (IM) are the most significant risk factors for gastric cancer. Therefore, the accurate selection of individuals with AG and IM may be a key strategy for the prevention and/or early detection of gastric cancer. Although endoscopic evaluation using enhanced technologies such as narrow band imaging-magnification, the serum pepsinogen test, Helicobacter pylori serology, and trefoil factor 3 have been evaluated, a gold standard method to accurately select individuals with AG and IM has not emerged. In terms of managing patients at high risk of gastric cancer, it remains uncertain whether H. pylori eradication reverses and/or prevents the progression of AG and IM. Although endoscopic surveillance in high risk patients is expected to be beneficial, further prospective studies in large populations are needed to determine the optimal surveillance interval.

Spatially defined microsatellite analysis reveals extensive genetic mosaicism and clonal complexity in intestinal metaplastic glands

Intestinal metaplasia (IM) has been recognized as the first irreversible precancerous stage of intestinal-type gastric cancer at which genetic instabilities, such as microsatellite (MS) instability and loss of heterozygosity, can already be detected. However, the extent and clonal relationship of these genetic lesions in the precancerous tissues are not fully appreciated. In this work, we have used well established MS markers to analyze the relatedness of spatially separated individual metaplastic glands as well as subsegments within single glands from the same patients. We found that individual IM glands frequently show different marker lengths even for closely apposed IM glands, suggesting that these tissues have already gained the ability to independently evolve their genome regardless of whether or not they share a common origin. Furthermore, within individual IM glands, there is also significant intra-gland diversity in the MS markers. Since most of these cells are not dividing and only have a limited lifespan, this result indicates that in each IM gland, a single dominant clone is rare and new clones are constantly created by either progenitor cells or stem cells. This greatly enhanced ability to create de novo genetic alterations may underlie the importance of this stage in the eventual progression toward cancer. Given the widely observed phenotype switch in the early stages of many solid tumors, whether this associated genetic stability is also an intrinsic property of metaplastic transformation should be extensively characterized to further our understanding of cancer initiation.

Tobacco smoking and intestinal metaplasia: Systematic review and meta-analysis

BACKGROUND

The evaluation of specific risk factors for early endpoints in the gastric carcinogenesis pathway may further contribute to the understanding of gastric cancer aetiology.

AIMS

To quantify the relation between smoking and intestinal metaplasia through systematic review and meta-analysis.

METHODS

Articles providing data on the association between smoking and intestinal metaplasia were identified in PubMed(®), Scopus(®) and Web of Science™, searched until April 2014, and through backward citation tracking. Summary odds ratio estimates and 95% confidence intervals were computed using the DerSimonian and Laird method. Heterogeneity was quantitatively assessed using the I(2) statistic.

RESULTS

A total of 32 articles were included in this systematic review and 19 provided data for meta-analysis. Smoking was defined as ever vs. never (crude estimates, six studies, summary odds ratio=1.54, 95% confidence interval: 1.12-2.12, I(2)=67.4%; adjusted estimates, seven studies, summary odds ratio=1.26, 95% confidence interval: 0.98-1.61, I(2)=65.0%) and current vs. non-smokers (crude estimates, seven studies, summary odds ratio=1.27, 95% confidence interval: 0.88-1.84, I(2)=73.4%; adjusted estimates, two studies, summary odds ratio 1.49, 95% confidence interval: 0.99-2.25, I(2)=0.0%).

CONCLUSION

The weak and non-statistically significant association found through meta-analysis of the available evidence does not confirm smoking as an independent risk factor for intestinal metaplasia.

Changing prevalence patterns in endoscopic and histological diagnosis of gastritis? Data from a cross-sectional Central European multicentre study

BACKGROUND AND AIMS

Traditionally, Helicobacter infection is considered to be the most common cause of gastritis. In the cross-sectional Central European histoGERD trial, we assessed the prevalence of different types of gastritis, correlating histological and endoscopic diagnoses.

METHODS

A total of 1123 individuals participated in an observational multicentre study. Endoscopists classified individuals as positive or negative for gastritis and rendered the putative cause. Pathologists evaluated biopsy specimens based upon the Updated Sydney System.

RESULTS

Histological diagnosis of gastritis was made in 639 (56.9%) participants. In all, 210 (18.7%) individuals were diagnosed with Helicobacter gastritis, 215 (19.1%) with post Helicobacter gastritis, 234 (20.8%) with reactive gastropathy, 26 (2.3%) with autoimmune gastritis, and 6 (0.5%) with focally enhanced gastritis related to Crohn's disease. In 46 out of 639 (7.2%) individuals diagnosed with gastritis, combinations of different histological subtypes were noted the most common being reactive gastropathy and post Helicobacter gastritis. Endoscopic diagnosis of gastritis was made in 534 (47.6%) individuals.

CONCLUSIONS

Reactive gastropathy was more common than active Helicobacter gastritis, and the majority of cases attributable to Helicobacter infection were no longer ongoing, i.e. post Helicobacter gastritis. Agreement between histological and endoscopic diagnoses was better in reactive gastropathy than in Helicobacter gastritis.

Diagnostic yield of the light blue crest sign in gastric intestinal metaplasia: a meta-analysis

BACKGROUND

The diagnostic yield of light blue crest(LBC) sign, which was observed by narrow band imaging with magnification endoscopy(NBI-ME), in detecting gastric intestinal metaplasia(IM) has shown variable results.

OBJECTIVE

We aimed to assess the diagnostic value of LBC under NBI-ME for detecting gastric IM.

METHODS

We performed a literature search of the Medline/PubMed, Embase, Web of Science, Science Direct and the Cochrane Library Databases; and a meta-analysis of pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and SROC area under the curve, using fixed- and random-effects models, for the accuracy of LBC-based IM diagnosis.

RESULTS

We initially included 4 articles, but excluded 1 article to counter significant heterogeneity. When pooled, the remaining 3 articles, which included 247 patients with 721 lesions, showed the following patterns in IM diagnosis: sensitivity: 0.90 (95% confidence interval [CI] 0.86-0.92); specificity: 0.90 (95% CI 0.86-0.93), positive likelihood ratio: 8.98 (95% CI 6.42-12.58), negative likelihood ratio: 0.12 (95% CI 0.09-0.16), and SROC area under the curve: 0.9560.

LIMITATIONS

As the studies varied by their definitions for positive LBC, endoscopy types, biopsy protocols, race of patient cohort, and physicians' proficiency, some sample sizes were limited so that subgroup analyses could not be performed.

CONCLUSION

We concluded that observing LBC under NBI-ME is an accurate and precise means of diagnosing gastric IM.

Host Gene Polymorphisms in Relation to Helicobacter Pylori Infection and Associated Diseases in a Population Based Cohort

Background

This prospective population based cohort study explores possible associations between host gene polymorphisms, blood group and life style factors on the one hand, and Helicobacter pylori infection, peptic ulcer, and the grade of inflammation, atrophy and intestinal metaplasia of the gastric mucosa, on the other hand.

Methods

The study population (472 volunteers) has previously undergone screening with gastroduodenoscopy, biopsy and blood sampling. The host gene polymorphisms of IL1B-31C/T, IFNGR1-56T/C, the IL1RN VNTR in exon 2 and the HLA-DRB1 gene alleles were analyzed using PCR and pyrosequencing.

Results

H. pylori infection was negatively related to HLA DRB1*03 (odds ratio (OR) 95% CI: 0.388 - 0.989) and was more frequent in individuals with blood group O than A (OR 95% CI: 1.121 - 2.677). There was a lower risk of moderate to severe inflammation in the antrum among individuals with IL1B-31 TC compared to CC carriers (OR 95% CI: 0.094 - 0.733). The IL1RN*L2 genotype was associated with higher risk of IM in the antrum than the *LL genotype (OR 95% CI: 1.570 - 15.878). There was a negative relation between the HLA DRB1 alleles *04 (OR 95% CI: 0.234 - 0.831) and *08 (OR 95% CI: 0.013 - 0.915), and IM in the antrum.

Conclusion

The IL1RN VNTR and the IL1β-31 alleles seem to be associated with intestinal metaplasia of the corpus mucosa and the grade of inflammation of the antrum, respectively. However, no unambiguous correlations could be identified between the host polymorphisms and the occurrence of H. pylori infection, peptic ulcer, and the grade of inflammation, atrophy and IM of the gastric mucosa.

An inverse relationship between the expression of the gastric tumor suppressor RUNX3 and infection with Helicobacter pylori in gastric epithelial dysplasia

BACKGROUND/AIMS

This study was performed to determine the association between RUNX3 expression and Helicobacter pylori infection in premalignant gastric lesions.

METHODS

We examined 107 patients with gastric epithelial dysplasia who had undergone endoscopic mucosal resection or submucosal dissection. All tissue samples were evaluated by RUNX3 staining and subclassified by immunophenotype. H. pylori infection in dysplastic lesions and the normal surrounding tissue was examined by silver staining, and cagA status was assessed by polymerase chain reaction.

RESULTS

The loss of RUNX3 expression was observed in 62 cases (57.9%), and an association with H. pylori infection was found in 54 cases (50.5%). The infection rate with the cagA-positive H. pylori strain was 63.0%. In RUNX3-negative lesions, the rate of H. pylori infection (p=0.03) and the frequency of category 4 lesions (according to the revised Vienna classification) were high (p=0.02). In addition, the gastric mucin phenotype was predominant. In RUNX3-negative category 4 lesions, the rate of cagA-positive H. pylori infection rate was high but not significantly increased (p=0.08).

CONCLUSIONS

Infection with H. pylori is associated with inactivation of RUNX3 in early gastric carcinogenesis. This mechanism was prominent in gastric cancer with a gastric mucin phenotype.

Narrow-band imaging with magnifying endoscopy is accurate for detecting gastric intestinal metaplasia

AIM

To investigate the predictive value of narrow-band imaging with magnifying endoscopy (NBI-ME) for identifying gastric intestinal metaplasia (GIM) in unselected patients.

METHODS

We prospectively evaluated consecutive patients undergoing upper endoscopy for various indications, such as epigastric discomfort/pain, anaemia, gastro-oesophageal reflux disease, suspicion of peptic ulcer disease, or chronic liver diseases. Patients underwent NBI-ME, which was performed by three blinded, experienced endoscopists. In addition, five biopsies (2 antrum, 1 angulus, and 2 corpus) were taken and examined by two pathologists unaware of the endoscopic findings to determine the presence or absence of GIM. The correlation between light blue crest (LBC) appearance and histology was measured. Moreover, we quantified the degree of LBC appearance as less than 20% (+), 20%-80% (++) and more than 80% (+++) of an image field, and the semiquantitative evaluation of LBC appearance was correlated with IM percentage from the histological findings.

RESULTS

We enrolled 100 (58 F/42 M) patients who were mainly referred for gastro-esophageal reflux disease/dyspepsia (46%), cancer screening/anaemia (34%), chronic liver disease (9%), and suspected celiac disease (6%); the remaining patients were referred for other indications. The prevalence of Helicobacter pylori (H. pylori) infection detected from the biopsies was 31%, while 67% of the patients used proton pump inhibitors. LBCs were found in the antrum of 33 patients (33%); 20 of the cases were classified as LBC+, 9 as LBC++, and 4 as LBC+++. LBCs were found in the gastric body of 6 patients (6%), with 5 of them also having LBCs in the antrum. The correlation between the appearance of LBCs and histological GIM was good, with a sensitivity of 80% (95%CI: 67-92), a specificity of 96% (95%CI: 93-99), a positive predictive value of 84% (95%CI: 73-96), a negative predictive value of 95% (95%CI: 92-98), and an accuracy of 93% (95%CI: 90-97). The NBI-ME examination overlooked GIM in 8 cases, but the GIM was less than 5% in 7 of the cases. Moreover, in the 6 false positive cases, the histological examination showed the presence of reactive gastropathy (4 cases) or H. pylori active chronic gastritis (2 cases). The semiquantitative correlation between the rate of LBC appearance and the percentage of GIM was 79% (P < 0.01).

CONCLUSION

NBI-ME achieved good sensitivity and specificity in recognising GIM in an unselected population. In routine clinical practice, this technique can reliably target gastric biopsies.

Expression of Das-1, Ki67 and sulfuric proteins in gastric cardia adenocarcinoma and intestinal metaplasia lesions

The aim of this study was to characterize histo-chemical patterns and Das-1 and Ki67 protein expression in gastric cardia adenocarcinoma (GCA) and intestinal metaplasia (IM) lesions adjacent to GCA. Histochemical techniques, including Alcian blue/periodic acid-Schiff (AB/PAS), high iron diamine/Alcian blue (HID/AB) and avidin-biotin-peroxidase complex (ABC) immunohistochemistry were applied to GCA and IM samples from patients (n=200) in Linzhou, Henan, China, a high incidence area for GCA and esophageal squamous cell carcinoma (SCC). The detection rate of IM lesions in resected tissues adjacent to GCA was 32.5% (65/200). GCA and IM lesions presented a high frequency of Das-1 and Ki67-positive staining with statistical significance (P<0.01). The expression of sulfuric proteins did not show co-expression with Das-1 and Ki67 in GCA and surrounding IM lesions (P>0.05) from the same GCA patient. The high frequency of co-expression of Das-1 and Ki67 in GCA and adjacent IM lesions indicates that IM adjacent to GCA may undergo similar molecular changes to GCA, which may be one of the mechanisms for malignant transformation of IM in the population studied.

Intestinal metaplasia surveillance: Searching for the road-map

Atrophic gastritis and intestinal metaplasia (IM) of the stomach are common and are associated with an increased risk for gastric cancer. In the absence of guidelines, a pragmatic management has been performed in Western countries in patients with these premalignant conditions. Recently, formal European guidelines have been delivered on this topic. Basically, it has been recommended that patients with extensive atrophic gastritis (AG) and/or extensive IM should be offered endoscopic surveillance every 3 years. On the contrary, no scheduled endoscopic/histological control has been advised for those patients with precancerous conditions confined to the antrum. In this commentary, we highlighted some potential weaknesses in the management formally recommended by the new guidelines. In detail, we discussed that AG and IM patients do not share the same gastric cancer risk, at least in Western countries, deserving a different approach. Some factors significantly associated with gastric cancer risk, such as IM type, first-degree family history of gastric cancer, and smoking habit have not been considered in tailoring the endoscopic follow-up. Finally, some data would suggest that a 3-year follow-up in patients with extensive gastric precancerous conditions could result in an inadequate secondary prevention.