Acetic acid chromoendoscopy for determining the extent of gastric intestinal metaplasia

Image-enhanced endoscopy in the diagnosis of gastric premalignant conditions and gastric cancer

Diagnosis of early gastric cancer and its precancerous lesions remains a challenge for great part of western endoscopists. Changes seen in the mucosal pattern are generally subtle and hence difficult to identify. In this article, we will review the usefulness of conventional and virtual chromoendoscopy and magnification endoscopy in the recognition and classification of these lesions.

Endoscopic Imaging for the Diagnosis of Neoplastic and Pre-Neoplastic Conditions of the Stomach

Gastric cancer is an aggressive disease with low long-term survival rates. An early diagnosis is essential to offer a better prognosis and curative treatment. Upper gastrointestinal endoscopy is the main tool for the screening and diagnosis of patients with gastric pre-neoplastic conditions and early lesions. Image-enhanced techniques such as conventional chromoendoscopy, virtual chromoendoscopy, magnifying imaging, and artificial intelligence improve the diagnosis and the characterization of early neoplastic lesions. In this review, we provide a summary of the currently available recommendations for the screening, surveillance, and diagnosis of gastric cancer, focusing on novel endoscopy imaging technologies.

Need for improvement in the evaluation of pre-malignant upper gastro-intestinal lesions in India: Results of a nationwide survey

BACKGROUND AND AIM

Gastric and esophageal cancers are associated with high morbidity in India. In the absence of formal screening programs in India, it is essential that all elective esophago-gastro-duodenoscopies (EGDs), irrespective of indication, be also considered an opportunity to screen for premalignant lesions. With this premise, we tried to assess the adherence to best practices in the detection of premalignant upper gastro-intestinal lesions (PMUGIL) among endoscopists in India. We also evaluated the adequacy of training, availability of appropriate facilities, and differences between teaching and non-teaching centers.

METHODS

We disbursed a survey among endoscopists working in India, through the membership database of the Society of Gastrointestinal Endoscopists of India, by email and instant messaging. The responses were collected and subsequently analyzed.

RESULTS

We obtained a total of 422 eligible responses. The adherence to best practices assessed was lower than the set threshold in all except one parameter in both teaching centers and non-teaching centers. Only 58.5% of endoscopists had received training in the detection of PMUGIL. Appropriate image enhanced endoscopy (IEE) facilities were available to only 58.05% of surveyed endoscopists.

CONCLUSIONS

Strategies to improve detection of PMUGIL should be directed at improving adherence to best practices, ensuring adequate training of endoscopists in the evaluation of PMUGIL and improving infrastructure.

Endoscopic Advances for Gastric Neoplasia Detection

This article explores advances in endoscopic neoplasia detection with supporting clinical evidence and future aims. The ability to detect early gastric neoplastic lesions amenable to curative endoscopic submucosal dissection provides the opportunity to decrease gastric cancer mortality rates. Newer imaging techniques offer enhanced views of mucosal and microvascular structures and show promise in differentiating benign from malignant lesions and improving targeted biopsies. Conventional chromoendoscopy is well studied and validated. Narrow band imaging demonstrates superiority over magnified white light. Autofluorescence imaging, i-scan, flexible spectral imaging color enhancement, and bright image enhanced endoscopy show promise but insufficient evidence to change current clinical practice.

Improving the Early Diagnosis of Gastric Cancer

Gastric cancer (GC) remains a leading cause of cancer morbidity and mortality worldwide. Outcomes from GC remain poor, especially in Western nations where cancer diagnosis is usually at advanced stages where curative resection is not possible. By contrast, nations of East Asia have adopted methods of population-level screening with improvements in stage of diagnosis and survival. In this review, the authors discuss the epidemiology of GC in Western populations, highlight at-risk populations who may benefit from screening, overview screening modalities, and discuss promising approaches to early GC detection.

Comparison of white-light endoscopy, optical-enhanced and acetic-acid magnifying endoscopy for detecting gastric intestinal metaplasia: A randomized trial

BACKGROUND

Gastric intestinal metaplasia (GIM) is a precancerous lesion of the stomach, which severely affects human life and health. Currently, a variety of endoscopic techniques are used to screen/evaluate GIM. Traditional white-light endoscopy (WLE) and acetic-acid chromoendoscopy combined with magnifying endoscopy (ME-AAC) are the interventions of choice due to their diagnostic efficacy for GIM. Optical-enhanced magnifying endoscopy (ME-OE) is a new virtual chromoendoscopy technique to identify GIM, which combines bandwidth-limited light and image enhancement processing technology to enhance the detection of mucosal and vascular details. We hypothesized that ME-OE is superior to WLE and ME-AAC in the evaluation of GIM.

AIM

To directly compare the diagnostic value of WLE, ME-AAC, and ME-OE for detection of GIM.

METHODS

A total of 156 patients were subjected to consecutive upper gastrointestinal endoscopy examinations using WLE, ME-AAC, and ME-OE. Histopathological findings were utilized as the reference standard. Accuracy, sensitivity, specificity, and positive and negative predictive values of the three endoscopy methods in the diagnosis of GIM were evaluated. Moreover, the time to diagnosis with ME-AAC and ME-OE was analyzed. Two experts and two non-experts evaluated the GIM images diagnosed using ME-OE, and diagnostic accuracy and intra- and inter-observer agreement were analyzed.

RESULTS

GIM was detected in 68 of 156 patients (43.6%). The accuracy of ME-OE was highest (91.7%), followed by ME-AAC (86.5%), while that of WLE (51.9%) was lowest. Per-site analysis showed that the overall diagnostic accuracy of ME-OE was higher than that of ME-AAC (P = 0.011) and WLE (P < 0.001). The average diagnosis time was lower in ME-OE than in ME-AAC (64 ± 7 s vs 151 ± 30 s, P < 0.001). Finally, the inter-observer agreement was strong for both experts (k = 0.862) and non-experts (k = 0.800). The internal consistency was strong for experts (k = 0.713, k = 0.724) and moderate for non-experts (k = 0.667, k = 0.598).

CONCLUSION

For endoscopists, especially experienced endoscopists, ME-OE is an efficient, convenient, and time-saving endoscopic technique that should be used for the diagnosis of GIM.

KLF5 promotes HpSlyD induced gastric intestinal metaplasia by activating Wnt/β-catenin pathway

BACKGROUND

Krüppel like factor 5 (KLF5) and the Wnt/β-catenin pathway are hot topics in the research of tumorigenesis. Some studies have found that KLF5 is related to the differentiation and proliferation of intestinal epithelial cells, suggesting that KLF5 may be involved in the occurrence of intestinal metaplasia. However, there are few reports on the effect of KLF5 on intestinal metaplasia and the underlying molecular mechanism.

AIM

To explore the effect of KLF5 on gastric intestinal metaplasia (GIM) induced by Helicobacter pylori (H. pylori) and the underlying mechanism.

METHODS

The mRNA and protein expression of KLF5 and Wnt3a was detected by RT-PCR and Western blot, respectively. Gastric epithelial cell line GES1 was cultured in vitro and divided into a blank control group, HpSlyD group (200 ng/mL HpSlyD + negative sequence), KLF5 interference group (200 ng/mL HpSlyD + KLF5 siRNA), Wnt agonist group (200 ng/mL HpSlyD + KLF5 siRNA + lithium chloride), and Wnt agonist + KLF5 interference group. GES1 cell proliferation and apoptosis were determined by MTT assay and flow cytometry, respectively. RT-PCR was used to detect KLF5, Wnt3a, beta-catenin, wool protein 1 (VIL1), trefoil factor 2 (TFF2), and caudal homeobox factor 2 (CDX2) mRNA expression. The expression of VIL1, TFF2, and CDX2 proteins was detected by Western blot.

RESULTS

The expression of KLF5 and Wnt3a mRNA and protein in intestinal metaplasia was significantly higher than that in the normal gastric mucosa (P < 0.01). The cell proliferation rates in the HpSlyD group and interference control group were significantly higher than that of the blank control group, and the apoptosis rates were significantly lower than that of the blank control group (P < 0.05). The cell proliferation rate of the KLF5 interference group was significantly lower than that of the HpSlyD group, and the apoptosis rate was significantly higher than that of the HpSlyD group (P < 0.05). The mRNA and protein expression of VIL1, TFF2, and CDX2 in the HpSlyD group and interference control group was significantly higher than that of the blank control group (P < 0.05), while the mRNA and protein expression of VIL1, TFF2, and CDX2 in the KLF5 interference group were significantly lower than those of the HpSlyD group (P < 0.05). The expression of Wnt3a, β-catenin, and CDX2 mRNA in the KLF5 interference group was significantly lower than that of the HpSlyD group (P < 0.05). The expression of Wnt3a, β-catenin, and CDX2 mRNA in the Wnt agonist + KLF5 interference group was significantly higher than that of the KLF5 interference group (P < 0.05).

CONCLUSION

Interference of KLF5 expression can significantly inhibit HpSlyD induced gastric metaplasia. KLF5 may promote HpSlyD induced gastric metaplasia by activating the Wnt/β-catenin pathway, which provides a new target for clinical prevention of gastric cancer.

Optical effect of spraying l-menthol on gastric intestinal metaplasia visualized by linked color imaging

OBJECTIVE

Linked color imaging (LCI) enables noninvasive detection of gastric intestinal metaplasia (GIM) as a lavender color sign (LCS), and there has been a recent report that l-menthol enhanced GIM with LCI. We measured color values of GIM and surrounding mucosa with white light imaging (WLI), LCI and LCI after spraying l-menthol (Mint-LCI) and investigated the effect of l-menthol on gastric mucosa.

METHODS

Endoscopic images of the antrum with WLI, LCI and Mint-LCI from 18 patients were prepared. Each of six regions of interest (three points of GIM and three points of surrounding mucosa) was selected for each modality, and CIE1976 (L*a*b*) color space was used to measure the color values. The primary endpoint was color differences (ΔE) between GIM and surrounding mucosa in each modality.

RESULTS

For surrounding mucosa, the mean a* value with Mint-LCI was significantly higher than the mean values with WLI and LCI (P < 0.01). The mean b* value of GIM with LCI was significantly lower than that of surrounding mucosa, and spraying l-menthol decreased the b* values of GIM with a change to a deeper lavender color (LCI: 10.0 ± 5.8, Mint-LCI: 3.7 ± 6.1, P < 0.01). However, there was no significant difference in mean ΔE values between LCI and Mint LCI (LCI: 21.1 ± 6.6, Mint-LCI: 22.7 ± 5.4, NS). After spraying l-menthol, the microstructure of GIM changed to translucent and microvessels were obscured.

CONCLUSIONS

As shown by LCI, spraying l-menthol optically enhances the color of GIM in the antrum.

Optical enhancement imaging versus acetic acid for detecting gastric intestinal metaplasia: A randomized, comparative trial

BACKGROUND AND AIMS

The diagnosis of gastric intestinal metaplasia (GIM) is still challenging. Optical Enhancement technology (OE) may improve the detection of GIM. We compared detection of GIM with OE, acetic acid and the Sydney biopsy protocol in a surveillance population.

METHODS

Consecutive patients with atrophic gastritis or known GIM were prospectively included. The stomach was examined with high definition whitelight endoscopy, followed by OE or acetic acid with targeted biopsies (1:1 randomisation). Subsequently, five random biopsies were taken according to the updated Sydney system.

RESULTS

A total of 154 patients were randomized. Higher proportions of patients with GIM were detected by OE and acetic acid versus random biopsy (60.5% vs 35.5%, 67.1% vs 31.5%, respectively; P < 0.0001 for both comparisons). The combined use of targeted biopsies and random biopsies provides high diagnostic yields for GIM (78.9% in OE group and 83.6% in acetic acid group). In addition, the proportion of extensive GIM was significantly increased when image enhanced endoscopy was used instead of white light endoscopy (P = 0.029, P = 0.048, respectively).

CONCLUSIONS

OE and acetic acid showed comparable results diagnosing GIM in the study. Targeted biopsies plus random biopsies should be used complementary in high risk populations.

Novel endoscopic findings as visualized by non-magnification endoscopy with linked color imaging are indicative of gastric intestinal metaplasia

BACKGROUND

Gastric intestinal metaplasia (GIM) is generally considered to be the main mucosal background for the development of gastric adenocarcinomas. Using linked color imaging (LCI), we noticed that the color pattern in areas of GIM was purple mixed with white on the epithelium with signs of mist that were detected by the non-magnifying LCI observation. We have termed this endoscopic finding "Purple in Mist" (PIM). The aim of this study was to investigate whether PIM could be a useful optical sign for predicting GIM.

METHODS

We prospectively evaluated consecutive patients undergoing endoscopy for various indications. The endoscopist used the LCI system to carefully observe the gastric antrum, body and angulus. When a PIM was identified in the surface layer, targeted biopsies were subsequently taken from this part. If the suspected area had no PIM on the surface, targeted biopsies were also taken.

RESULTS

Sixty-three consecutive patients were included in this study. The prevalence of intestinal metaplasia (IM) was 29/63 (46%). In PIM-positive patients, the prevalence of IM was 23/26 (89%). Of these patients, 146 biopsy specimens were included in this study. For the diagnosis of IM, compared to histological assessment, the LCI finding had an accuracy of 91.1% (95%CI: 86.5%-95.7%), a sensitivity of 89.8% (95%CI: 81.3%-98.3%), a specificity of 91.8% (95%CI: 86.3%-97.2%), a positive predictive value of 84.6% (95%CI: 74.8%-94.4%), and a negative predictive value of 94.7% (95%CI: 90.1%-99.2%).

CONCLUSIONS

A positive PIM finding in a suspicious lesion on LCI would complement LCI diagnosis of possible IM because of the positive predictive value of PIM. PIM could be a novel endoscopic marker for IM.

TRIAL REGISTRATION

ClinicalTrials.gov, No. NCT03092414; https://clinicaltrials.gov/ct2/show/NCT03092414?id=NCT03092414&rank=1.

Blue laser imaging with acetic acid enhancement improved the detection rate of gastric intestinal metaplasia

Our aim was to evaluate the ability of blue laser imaging (BLI) combined with acetic acid (BLI-AA) to detect gastric intestinal metaplasia (GIM). Participants undergoing gastroscopy from July 2017 to February 2018 in our hospital were enrolled prospectively. The abilities of white light imaging endoscopy, BLI endoscopy, and BLI-AA to detect GIM were compared. One hundred six patients undergoing gastroscopy met the inclusion criteria. GIM was diagnosed in 41 patients. For BLI-AA, the sensitivity, specificity, positive predictive, and negative predictive values were 85.4%, 84.6%, 77.8%, and 90.2% respectively. The diagnostic accuracy rate for BLI-AA was 84.9%, which was higher than that of white light imaging endoscopy and BLI endoscopy. For target biopsy, the GIM detection rate for the BLI-AA mode was significantly higher (77.8%, 105/135) than that for the BLI mode (58.3%, 84/144) or the white light endoscopy mode (40.4%, 57/141) (p < 0.05). BLI-AA is an efficient and simple method for the detection of GIM.

Past and current trends in endoscopic diagnosis for early stage gastric cancer in Japan

Methodology for the diagnosis and staging of early gastric cancer (EGC) has improved in Japan since the development of the gastro-camera and determination of a definition of EGC. Imaging technology has been steadily evolving in the endoscopy field. Improvements in the resolution of standard endoscopy images used in screening and surveillance provide greater opportunities to find gastric cancer earlier. Image enhancement endoscopy (IEE), such as narrow band imaging (NBI), highlights mucosal structures and vascularity. In particular, when NBI is used with magnifying endoscopy, it reveals fine details of subtle superficial abnormalities of EGC that are difficult to recognize using standard white light endoscopy. IEE-assisted magnifying endoscopy has improved the accuracy of the differentiation of superficial gastric cancer as well as delineation of the diseased mucosa. The advanced imaging technology enables precise assessment of the risk of lymph node metastasis of EGC and is widely used to determine indications for endoscopic treatment. It is not an overstatement to say that this has become the basis for the current development and dissemination of endoscopic treatments. Moreover, the resolution of endoscopic imaging has been upgraded to the microscopy level by the development of endomicroscopy, including endocytoscopy and confocal laser endomicroscopy. Endomicroscopy allows real-time histological analysis of living tissue during routine endoscopy and may reduce the number of biopsies needed to reach the correct diagnosis, minimizing the risk of sampling errors.