In vivo histological diagnosis for gastric cancer using endocytoscopy

Gastric cystica profunda: Another indication for minimally invasive endoscopic resection techniques?

Gastric cancer presents a significant global health burden, as it is the fifth most common malignancy and fourth leading cause of cancer mortality worldwide. Variations in incidence rates across regions underscores the multifactorial etiology of this disease. The overall 5-year survival rate remains low despite advances in its diagnosis and treatment. Although surgical gastrectomy was previously standard-of-care, endoscopic resection techniques, including endoscopic mucosal resection and endoscopic submucosal dissection (ESD) have emerged as effective alternatives for early lesions. Compared to surgical resection, endoscopic resection techniques have comparable 5-year survival rates, reduced treatment-related adverse events, shorter hospital stays and lower costs. ESD also enables en bloc resection, thus affording organ-sparing curative endoscopic resection for early cancers. In this editorial, we comment on the recent publication by Geng et al regarding gastric cystica profunda (GCP). GCP is a rare gastric pseudotumour with the potential for malignant progression. GCP presents a diagnostic challenge due to its nonspecific clinical manifestations and varied endoscopic appearance. There are several gaps in the literature regarding the diagnosis and management of GCP which warrants further research to standardize patient management. Advances in endoscopic resection techniques offer promising avenues for GCP and early gastric cancers.

The diagnostic utility of endocytoscopy for the detection of gastric cancer: a systematic review and meta-analysis

INTRODUCTION

Endocytoscopy (ECS) is an evolving technology that utilizes ultra-high power magnification for real time cellular imaging without the need for physical biopsy. Its application for gastric cancer (GC) detection is not well evaluated at the current time, but there is potential that ECS can make a real time histopathological diagnosis to differentiate neoplastic from benign lesions. We aimed to investigate the diagnostic utility of ECS for GC detection.

EVIDENCE ACQUISITION

Literature searches through multiple databases were performed for studies using ECS for GC detection until November 2021. Measured outcomes included the pooled sensitivity, specificity and accuracy. Quality assessment of diagnostic studies tool was used to assess the risk of bias.

EVIDENCE SYNTHESIS

Four studies (N.=245) were included. The pooled sensitivity was 83.5% (95% CI: 75-89%, I2: 0) and specificity was 91.7% (95% CI: 79-97%, I2: 58%). The pooled accuracy was 89.2% (95% CI: 83-94%, I2: 38%). There was a low risk of bias.

CONCLUSIONS

ECS is an accurate diagnostic modality and has the potential to serve as a complimentary tool in screening for GC. Larger prospective studies are needed to validate these findings before its further widespread use.

Virtual Staining of Nonfixed Tissue Histology

Surgical pathology workflow involves multiple labor-intensive steps, such as tissue removal, fixation, embedding, sectioning, staining, and microscopic examination. This process is time-consuming and costly and requires skilled technicians. In certain clinical scenarios, such as intraoperative consultations, there is a need for faster histologic evaluation to provide real-time surgical guidance. Currently, frozen section techniques involving hematoxylin and eosin (H&E) staining are used for intraoperative pathology consultations. However, these techniques have limitations, including a turnaround time of 20 to 30 minutes, staining artifacts, and potential tissue loss, negatively impacting accurate diagnosis. To address these challenges, researchers are exploring alternative optical imaging modalities for rapid microscopic tissue imaging. These modalities differ in optical characteristics, tissue preparation requirements, imaging equipment, and output image quality and format. Some of these imaging methods have been combined with computational algorithms to generate H&E-like images, which could greatly facilitate their adoption by pathologists. Here, we provide a comprehensive, organ-specific review of the latest advancements in emerging imaging modalities applied to nonfixed human tissue. We focused on studies that generated H&E-like images evaluated by pathologists. By presenting up-to-date research progress and clinical utility, this review serves as a valuable resource for scholars and clinicians, covering some of the major technical developments in this rapidly evolving field. It also offers insights into the potential benefits and drawbacks of alternative imaging modalities and their implications for improving patient care.

β-Glucan-Mediated Oral Codelivery of 5FU and Bcl2 siRNA Attenuates Stomach Cancer

Based on cancer-related deaths, stomach cancer is ranked fifth, and first among Hispanics. Lack of technologies for early diagnosis and unavailability of target-specific therapeutics are largely the causes of the poor therapeutic outcomes from existing chemotherapeutics. Currently available therapeutic modalities are invasive and require systemic delivery, although the cancer is localized in the stomach at its early stage. Therefore, we hypothesize that an oral local delivery approach can extend the retention duration of the therapeutics modalities within the stomach and thereby enhance therapeutic efficacy. To accomplish this, we have developed a ß-glucan (BG)-based oral delivery vehicle that can adhere to the mucus lining of the stomach for an extended period while controlling the release of Bcl2 siRNA and 5-fluorouracil (5FU) payload for over 6 h. We found that Bcl2 siRNA selectively knocked down the Bcl2 gene in a C57BL/6 stomach cancer mouse model followed by upregulation of apoptosis and remission of cancer. BG was found to be very effective in maintaining the stability of siRNA for at least 6 h, when submerged in simulated gastric juice tested in vitro. To investigate the potential therapeutic effects in vivo, we used a stomach cancer mouse model, where C57BL/6 mice were treated with 5FU, BG/5FU, siRNA, BG/siRNA, and BG/5FU/siRNA. Higher inhibition of Bcl2 and therapeutic efficacy were observed in mice treated with BG/5FU/siRNA confirmed with Western blotting and a TUNEL assay. Significant reduction in the tumor region was observed with histology (H&E) and immunohistochemistry (Ki67, TUNEL, and Bcl2) analyses. Overall, the oral formulation shows improved efficacy with nonsignificant side effects compared to the conventional treatment tested in the gastric cancer mouse model.

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.

Global research trends of endoscope in early gastric cancer: A bibliometric and visualized analysis study over past 20 years

Objectives

Early gastric cancer (EGC) is defined as aggressive gastric cancer involving the gastric mucosa and submucosa. Early detection and treatment of gastric cancer are beneficial to patients. In recent years, many studies have focused on endoscopic diagnosis and therapy for EGC. Exploring new methods to analyze data to enhance knowledge is a worthwhile endeavor, especially when numerous studies exist. This study aims to investigate research trends in endoscopy for EGC over the past 20 years using bibliometric analysis.

Methods

Original articles and reviews examining the use of endoscopy for EGC published from 2000 to 2022 were retrieved from the Web of Science Core Collection, and bibliometric data were extracted. Microsoft Office Excel 2016 was used to show the annual number of published papers for the top 10 countries and specific topics. VOSviewer software was used to generate network maps of the cooccurrences of keywords, authors, and topics to perform visualization network analysis.

Results

In total, 1,009 published papers met the inclusion criteria. Japan was the most productive country and had the highest number of publications (452, 44.8%), followed by South Korea (183, 18.1%), and China (150, 14.9%). The National Cancer Center of Japan was the institution with the highest number of publications (48, 4.8%). Ono was the most active author and had the highest number of cited publications. Through the network maps, exploring endoscopic diagnosis and therapy were major topics. Artificial intelligence (AI), convolutional neural networks (CNNs), and deep learning are hotspots in endoscopic diagnosis. Helicobacter pylori eradication, second-look endoscopy, and follow-up management were examined.

Conclusions

This bibliometric analysis investigated research trends regarding the use of endoscopy for treating EGC over the past 20 years. AI and deep learning, second-look endoscopy, and management are hotspots in endoscopic diagnosis and endoscopic therapy in the future.

Research trends in endoscopic applications in early gastric cancer: A bibliometric analysis of studies published from 2012 to 2022

Background

Endoscopy is the optimal method of diagnosing and treating early gastric cancer (EGC), and it is therefore important to keep up with the rapid development of endoscopic applications in EGC. This study utilized bibliometric analysis to describe the development, current research progress, hotspots, and emerging trends in this field.

Methods

We retrieved publications about endoscopic applications in EGC from 2012 to 2022 from Web of Science™ (Clarivate™, Philadelphia, PA, USA) Core Collection (WoSCC). We mainly used CiteSpace (version 6.1.R3) and VOSviewer (version 1.6.18) to perform the collaboration network analysis, co-cited analysis, co-occurrence analysis, cluster analysis, and burst detection.

Results

A total of 1,333 publications were included. Overall, both the number of publications and the average number of citations per document per year increased annually. Among the 52 countries/regions that were included, Japan contributed the most in terms of publications, citations, and H-index, followed by the Republic of Korea and China. The National Cancer Center, based in both Japan and the Republic of Korea, ranked first among institutions in terms of number of publications, citation impact, and the average number of citations. Yong Chan Lee was the most productive author, and Ichiro Oda had the highest citation impact. In terms of cited authors, Gotoda Takuji had both the highest citation impact and the highest centrality. Among journals, Surgical Endoscopy and Other Interventional Techniques had the most publications, and Gastric Cancer had the highest citation impact and H-index. Among all publications and cited references, a paper by Smyth E C et al., followed by one by Gotoda T et al., had the highest citation impact. Using keywords co-occurrence and cluster analysis, 1,652 author keywords were categorized into 26 clusters, and we then divided the clusters into six groups. The largest and newest clusters were endoscopic submucosal dissection and artificial intelligence (AI), respectively.

Conclusions

Over the last decade, research into endoscopic applications in EGC has gradually increased. Japan and the Republic of Korea have contributed the most, but research in this field in China, from an initially low base, is developing at a striking speed. However, a lack of collaboration among countries, institutions, and authors, is common, and this should be addressed in future. The main focus of research in this field (i.e., the largest cluster) is endoscopic submucosal dissection, and the topic at the frontier (i.e., the newest cluster) is AI. Future research should focus on the application of AI in endoscopy, and its implications for the clinical diagnosis and treatment of EGC.

The crucial role of LncRNA MIR210HG involved in the regulation of human cancer and other disease

Long noncoding RNAs (lncRNAs) have evoked considerable interest in recent years due to their critical functions in the regulation of disease processes. Abnormal expression of lncRNAs is found in multiple diseases, and lncRNAs have been exploited for diverse medical applications. The lncRNA MIR210HG is a recently discovered lncRNA that is widely dysregulated in human disease. MIR210HG was described to have biological functions with potential roles in disease development, including cell proliferation, invasion, migration, and energy metabolism. And MIR210HG dysregulation was confirmed to have promising clinical values in disease diagnosis, treatment, and prognosis. In this review, we systematically summarize the expression profiles, roles, underlying mechanisms, and clinical applications of MIR210HG in human disease.

KLF5-mediated aquaporin 3 activated autophagy to facilitate cisplatin resistance of gastric cancer

BACKGROUND

Resistance to chemotherapeutic drugs limits the control of gastric cancer (GC) development. The study intended to probe into the mechanism of aquaporin 3 (AQP3) on the chemoresistance of GC.

METHODS

Cisplatin (CDDP)-resistant cells were constructed. Parental AGS and HGC-27 cells and their respective CDDP-resistant cells were transfected with AQP3 overexpression plasmid, AQP3 short hairpin RNA (sh-AQP3) and sh-Kruppel-like factor 5 (shKLF5). The expressions of AQP3 and factors related to autophagy (LC3 I, LC3 II, Atg5, Beclin-1, p62)/epithelial-mesenchymal transition (EMT; E-cadherin and snail) were assessed by Western blot and qRT-PCR. Cell counting kit-8 assay was adopted to test cell viability and half maximal inhibitory concentration (IC 50) was determined. Transwell assay was used for the examination of cell migration and invasion. The regulatory relationship of AQP3 and KLF5 was tested by chromatin immunoprecipitation (ChIP) and dual luciferase reporter assays.

RESULTS

AQP3 was highly-expressed in GC cells and its level was even higher in CDDP-resistant GC cells. AQP3 silencing inhibited viability, autophagy and EMT in CDDP-resistant GC cells, while AQP3 overexpression had the opposite effect. KLF5 positively modulated AQP3 in GC cells resistant to CDDP. KLF5 knockdown reversed AQP3-induced autophagy, viability, migration, invasion and EMT in CDDP-resistant GC cells.

CONCLUSION

KLF5-modulated AQP3 activated autophagy to facilitate the resistance of GC to CDDP.

The development and clinical application of microscopic endoscopy for in vivo optical biopsies: Endocytoscopy and confocal laser endomicroscopy

Endoscopies are crucial for detecting and diagnosing diseases in gastroenterology, pulmonology, urology, and other fields. To accurately diagnose diseases, sample biopsies are indispensable and are currently considered the gold standard. However, random 4-quadrant biopsies have sampling errors and time delays. To provide intraoperative real-time microscopic images of suspicious lesions, microscopic endoscopy for in vivo optical biopsy has been developed, including endocytoscopy and confocal laser endomicroscopy. This article reviews recent advances in technology and clinical applications, as well as their shortcomings and future directions.

Evaluation of Microvascular Patterns Alone Using Endocytoscopy with Narrow-Band Imaging for Diagnosing Gastric Cancer

INTRODUCTION

Although endocytoscopy (EC) with narrow-band imaging (NBI) is effective in diagnosing gastric cancer, no diagnostic system has been validated. We explored a specific diagnostic system for gastric cancer using EC with NBI.

METHODS

Equal numbers of images from cancerous and noncancerous areas (114 images each) were assessed by endoscopists with (development group: 33) and without (validation group: 28) specific training in magnifying endoscopy with NBI. Microvascular and microsurface patterns (MS) in each image were evaluated. Lesions were diagnosed as cancerous when patterns were deemed "irregular." The accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of a diagnosis according to patterns on EC with NBI (microvascular pattern [MV] alone, MS alone, and both) were evaluated and compared between groups to determine the diagnostic performance.

RESULTS

In the development and validation groups, diagnoses based on the MV alone had significantly higher accuracy (91.7% vs. 76.3%, p < 0.0001 and 92.5% vs. 67.5%, p < 0.0001, respectively) and sensitivity (88.6% vs. 68.3%, p < 0.0001 and 89.5% vs. 38.6%, p < 0.0001, respectively) than those based on the MS alone. In both groups, there were no significant differences in diagnostic accuracy between using the MV alone and both patterns.

DISCUSSION/CONCLUSION

Evaluation of the MV alone is a simple and accurate diagnostic method for gastric cancer. This system could find widespread applications in clinical practice.

Endoscopic Classifications of Early Gastric Cancer: A Literature Review

Simple Summary

Throughout the years, endoscopic technologies have advanced to facilitate better assessment of gastric lesions and early detection of gastric cancer. With improvements in conventional white light endoscopy, we have also witnessed the development of newer endoscopic diagnostic modalities, giving rise to several classifications for early gastric cancer. Different endoscopic classifications of early gastric based on several endoscopic diagnostic modalities were included in this review. In addition to this, newer and novel endoscopic classifications that were specifically developed for the stomach for assessing and diagnosing gastric lesions have also been included. Illustrative representations of each classification have also been provided to aid readers in better understanding of these endoscopic classifications of early gastric cancer.

Abstract

Endoscopic technologies have been continuously advancing throughout the years to facilitate improvement in the detection and diagnosis of gastric lesions. With the development of different endoscopic diagnostic modalities for EGC, several classifications have been advocated for the evaluation of gastric lesions, aiming for an early detection and diagnosis. Sufficient knowledge on the appearance of EGC on white light endoscopy is fundamental for early detection and management. On the other hand, those superficial EGC with subtle morphological changes that are challenging to be detected with white light endoscopy may now be clearly defined by means of image-enhanced endoscopy (IEE). By combining magnifying endoscopy and IEE, irregularities in the surface structures can be evaluated and highlighted, leading to improvements in EGC diagnostic accuracy. The main scope of this review article is to offer a closer look at the different classifications of EGC based on several endoscopic diagnostic modalities, as well as to introduce readers to newer and novel classifications, specifically developed for the stomach, for the assessment and diagnosis of gastric lesions.

Unified magnifying endoscopic classification for esophageal, gastric and colonic lesions: a feasibility pilot study

Background and study aims  Image-enhanced magnifying endoscopy allows optimization of the detection and diagnosis of lesions found in the gastrointestinal tract. Current organ-specific classifications are well-accepted by specialized endoscopists but may pose confusion for general gastroenterologists. To address this, our group proposed the Unified Magnifying Endoscopic Classification (UMEC) which can be applied either in esophagus, stomach, or colon. The aim of this study was to evaluate the diagnostic performance and clinical applicability of UMEC. Patients and methods  A single-center, feasibility pilot study was conducted. Two endoscopists with experience in magnifying narrow band imaging (NBI), blinded to white-light and non-magnifying NBI findings as well as histopathological diagnosis, independently reviewed and diagnosed all images based on UMEC. In brief, UMEC is divided into three categories: non-neoplasia, intramucosal neoplasia, and deep submucosal invasive cancer. The diagnostic performance of UMEC was assessed while using the gold standard histopathology as a reference. Results  A total of 303 gastrointestinal lesions (88 esophageal squamous lesions, 90 gastric lesions, 125 colonic lesions) were assessed. The overall accuracy for both endoscopists in the diagnosis of esophageal squamous cell cancer, gastric cancer, and colorectal cancer were 84.7 %, 89.5 %, and 83.2 %, respectively. The interobserver agreement for each organ, Kappa statistics of 0.51, 0.73, and 0.63, was good. Conclusions  UMEC appears to be a simple and practically acceptable classification, particularly to general gastroenterologists, due to its good diagnostic accuracy, and deserves further evaluation in future studies.

Overexpressed versican promoted cell multiplication, migration and invasion in gastric cancer

Versican (VCAN) is verified to promote development among many cancers, whose function on gastric cancer (GC) is less studied. This work explored the effect of VCNA on GC. The differentially expressed VCAN between tumor and normal samples, among different cancer stages and the overall survival of GC patients with high and low VCAN levels were predicted through Gene Expression Profiling Interactive Analysis 2 (GEPIA2). The association between VCAN and clinicopathological parameters was analyzed by clinical investigation. AGS and NCI-N87 cells were transfected with VCAN short hairpin RNA (shVCAN) and VCAN overexpression plasmid. The VCNA, Cyclin D1, Cyclin E, E-Cadherin, N-Cadherin and Vimentin expression was detected through quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and Western blot. Cell viability was assessed through MTT assay. Cell migration was measured by wound healing assay and cell invasion was evaluated through Transwell assay. Cell cycle was determined by flow cytometry assay. VCAN was upregulated in GC and its high expression related to advanced TNM stage, Lymph node metastasis, Depth of invasion and Grade. VCAN knockdown inhibited multiplication, migration, invasion, Cyclin D1, Cyclin E, N-Cadherin and Vimentin expression while induced cycle arrest and E-Cadherin level of GC cells, whereas overexpressed VCAN showed opposite results. VCAN had a potential to be a biomarker for GC and overexpressed VCAN promoted GC cell multiplication, migration and invasion.

Application of Current Image-Enhanced Endoscopy in Gastric Diseases

Image-enhanced endoscopy (IEE) plays an integral role in endoscopic diagnosis and treatment. IEE enables an early and accurate detection of cancer and characterization of lesions prior to therapeutic decisions. Ideal IEE can serve as an optical or digital chromoscopic endoscopy, as well as an optical biopsy that predicts exact histopathology. Several IEE modalities have recently been developed and are used in the clinical field. The stomach is a challenging organ for imaging because of its complex secretion function and status of Helicobacter pylori infection. Therefore, understanding the current IEE modalities for their clinical applicability in an evidence-based approach is warranted. Along with technology refinements, the new paradigm will be available for the diagnosis of gastric cancer or other conditions in the stomach in the near future.

International cost-effectiveness analysis evaluating endoscopic screening for gastric cancer for populations with low and high risk

BACKGROUND

Gastric cancer remains one of the 3 most common causes of cancer death worldwide. Understanding the health and economic factors that affect screening cost-effectiveness in different countries will help address when and where it makes most sense to screen for gastric cancer.

METHODS

We performed a cost-effectiveness analysis using a Markov model to compare screening and surveillance strategies for gastric cancer in Brazil, France, Japan, Nigeria, and the United States. Primary outcome was the incremental cost-effectiveness ratio. We then performed a sensitivity analysis to determine how each variable affected the overall model.

RESULTS

In all countries, the most cost-effective strategies, measured by incremental cost-effectiveness ratio relative to no screening, were screening every 10 years, surveillance of high- and low-risk patients every 5 and 10 years, respectively, and screening every 5 years. Only Japan had at least one cost-effective screening strategy. The most important variables across different screening strategies and countries were starting age of screening, cost of endoscopy, and baseline probability of local gastric cancer at time of diagnosis.

CONCLUSIONS

Our model suggests that screening for gastric cancer is cost-effective in countries with higher incidence and lower costs of screening, but screening may still be a viable option in high-risk populations within low incidence countries.

Diagnostic performance in gastric cancer is higher using endocytoscopy with narrow-band imaging than using magnifying endoscopy with narrow-band imaging

BACKGROUND

For diagnosing gastric cancer, differences in the diagnostic performance between endocytoscopy with narrow-band imaging and magnifying endoscopy with narrow-band imaging have not been reported. We aimed to clarify these differences by analyzing diagnoses made by endoscopists in Japan.

METHODS

This single-center retrospective cohort study used 106 cancerous and 106 non-cancerous images obtained via both modalities (total, 424 images) for diagnosis. Sixty-one endoscopists with varying experience levels from 45 institutions were included. Diagnostic accuracy, sensitivity, specificity, and positive and negative predictive values were evaluated to determine the diagnostic performance of each modality and compared using the Mann-Whitney U test.

RESULTS

Among all endoscopists, diagnostic accuracy, sensitivity, positive predictive value, and negative predictive value were higher with endocytoscopy with narrow-band imaging than with magnifying endoscopy with narrow-band imaging (percentage [95% confidence interval]: 78.8% [76.4-83.0%] versus 72.2% [69.3-73.6%], p < 0.0001; 82.1% [78.3-85.9%] versus 64.2% [60.4-69.8%], p < 0.0001; 88.7% [82.6-90.7%] versus 78.5% [75.4-85.1%], p = 0.0023; 79.0% [75.3-80.5%] versus 68.5% [66.4-71.6%], p < 0.0001, respectively). In the magnifying endoscopy with narrow-band imaging-trained group, these values were also higher with endocytoscopy with narrow-band imaging than with magnifying endoscopy with narrow-band imaging (p < 0.0001, p = 0.0001, p = 0.0143, and p < 0.0001, respectively). Diagnostic accuracy, sensitivity, and negative predictive value were higher with endocytoscopy with narrow-band imaging than with magnifying endoscopy with narrow-band imaging in the magnifying endoscopy with narrow-band imaging-untrained group (p = 0.0041, p = 0.0049, and p = 0.0098, respectively).

CONCLUSIONS

Diagnostic performance was higher using endocytoscopy with narrow-band imaging than using magnifying endoscopy with narrow-band imaging. Our results may help change the technique used to diagnose gastric cancer.

Endocytoscopy: technology and clinical application in upper gastrointestinal tract

Over the past few years, the innovative field of magnifying endoscopy has been expanding with various cutting-edge technologies, one of which is endocytoscopy, to facilitate improvement in the detection and diagnosis of gastrointestinal lesions. Endocytoscopy is a novel ultra-high magnification endoscopic technique enabling high-quality in-vivo assessment of lesions found in the gastrointestinal tract with the use of intraprocedural stains. The main scope of this review article is to offer a closer look at the latest endocytoscopic technology and its clinical application in the upper gastrointestinal tract, especially in the esophagus and stomach, as well as to introduce readers to our simplified and up-to-date endocytoscopic classification, specifically developed for the esophagus and stomach, for the in-vivo assessment and diagnosis of esophageal and gastric lesions. Despite the good accuracy of endocytoscopy in the diagnosis of esophageal and gastric lesions in recent studies, some challenges still remain (e.g., staining method and standardized endocytoscopic classification). Through continuous evaluation and improvement of methods and skills, these challenges may be overcome thus establishing current techniques and classification, paving the way for further advances in the field of endocytoscopy and magnifying endoscopy. In all, endocytoscopy seems to aid in the in-vivo diagnosis of gastrointestinal tract lesions and may, in the future, revolutionize the field of in-vivo endoscopic diagnosis of gastrointestinal cancer, representing another step towards the so-called optical biopsy.

Recent advances in diagnostic upper endoscopy

BACKGROUND

Esophageo-gastro-duodenoscopy (EGD) is an important procedure used for detection and diagnosis of esophago-gastric lesions. There exists no consensus on the technique of examination.

AIM

To identify recent advances in diagnostic EGDs to improve diagnostic yield.

METHODS

We queried the PubMed database for relevant articles published between January 2001 and August 2019 as well as hand searched references from recently published endoscopy guidelines. Keywords used included free text and MeSH terms addressing quality indicators and technological innovations in EGDs. Factors affecting diagnostic yield and EGD quality were identified and divided into the follow segments: Pre endoscopy preparation, sedation, examination schema, examination time, routine biopsy, image enhanced endoscopy and future developments.

RESULTS

We identified 120 relevant abstracts of which we utilized 67 of these studies in our review. Adequate pre-endoscopy preparation with simethicone and pronase increases gastric visibility. Proper sedation, especially with propofol, increases patient satisfaction after procedure and may improve detection of superficial gastrointestinal lesions. There is a movement towards mandatory picture documentation during EGD as well as dedicating sufficient time for examination improves diagnostic yield. The use of image enhanced endoscopy and magnifying endoscopy improves detection of squamous cell carcinoma and gastric neoplasm. The magnifying endoscopy simple diagnostic algorithm is useful for diagnosis of early gastric cancer.

CONCLUSION

There is a steady momentum in the past decade towards improving diagnostic yield, quality and reporting in EGDs. Other interesting innovations, such as Raman spectroscopy, endocytoscopy and artificial intelligence may have widespread endoscopic applications in the near future.

Generation of magnifying endoscopic images of gastric neoplasms based on an all-in-focus algorithm

BACKGROUND AND AIM

Magnifying endoscopy is useful for diagnosis of early gastrointestinal neoplasms by visualizing microvascular (MV) and microsurface (MS) structures of the mucosa when combined with image-enhanced endoscopy. However, precise control of the endoscope is needed because the depth of focus is narrow and the target may move. These problems may be overcome by the all-in-focus (AIF) technique, which was developed in the engineering field. The aim of the study was to evaluate magnifying endoscopic image with AIF algorithm.

METHODS

Twenty gastric neoplasms were examined. Images were acquired at 80× magnification and converted to endoscopic images with an AIF algorithm (EI-AIF). The focus area and MV and MS patterns in the original image and the EI-AIF were compared on a 5-point Likert scale, where 5 indicates that the EI-AIF was superior. Intraclass correlation coefficients (ICCs) were used to assess the inter-evaluator reliability. An image quality measurement value was calculated for each image as an indicator of the degree of focus.

RESULTS

The scores for focus area, MV, and MS were 4.78 ± 0.45 (ICC = 0.63), 4.12 ± 0.76 (ICC = 0.70), and 4.72 ± 0.52 (ICC = 0.45), respectively, with the EI-AIF significantly superior for all three items (P < 0.05 by Student's t-test). ICCs for the focus area and MV were > 0.60, indicating strong inter-evaluator reliability. Image quality measurement was higher for the EI-AIF compared with the original image in every case.

CONCLUSIONS

Endoscopic observation with AIF algorithm gives a better image quality that allows easier evaluation of MV and MS patterns. This technique may resolve the difficulties with magnifying endoscopic observation.

Utilizing fourth-generation endocytoscopy and the 'enlarged nuclear sign' for in vivo diagnosis of early gastric cancer

Background and study aims  Fourth-generation endocytoscopy is an ultra-high magnification endoscopic technique designed to provide excellent quality in vivo histologic assessment of gastrointestinal lesions. This study aims to evaluate the diagnostic accuracy of endocytoscopy in early gastric cancer diagnosis. Patients and methods  A single-center, retrospective analysis of prospectively collected data from all gastric endocytoscopic examinations was conducted. Two expert endoscopists, blinded to white-light and narrow-band imaging findings as well as histopathologic diagnosis, independently reviewed and diagnosed all endocytoscopic images. A newly recognized "enlarged nuclear sign" was detected, and its implication in early gastric cancer diagnosis was evaluated. The diagnostic performance of fourth-generation endocytoscopy was assessed while using the gold standard histopathology as a reference. Results  Forty-three patients (mean age±SD, 72.6 ± 12.1 years; 31 males) were enrolled. Based on histopathology, 23 had well-differentiated adenocarcinomas, four adenomas, and 16 non-neoplastic lesions. The sensitivity, specificity, and accuracy of fourth-generation endocytoscopy for gastric cancer diagnosis were 87.0 % (95 % CI: 67.9 - 95.5), 80.0 % (95 % CI: 58.4 - 91.9), and 83.7 % (95 % CI: 70.0 - 91.9) by endoscopist A; and 91.3 % (95 % CI: 73.2 - 97.6), 75.0 % (95 % CI: 53.1 - 88.8), and 83.7 % (95 % CI: 70.0 - 91.9) by endoscopist B. The inter-observer agreement, Kappa statistic = 0.71 (95 % CI: 0.50 - 0.93), was good. The sensitivity, specificity, and accuracy of the enlarged nuclear sign for early gastric cancer diagnosis were 87.0 % (95 % CI: 67.9 - 95.5), 95.0 % (95 % CI: 76.4 - 99.1), and 90.7 % (95 % CI: 78.4 - 96.3) by endoscopist A; and 82.6 % (95 % CI: 62.9 - 93.0), 85.0 % (95 % CI: 64.0 - 94.8), and 83.7 % (95 % CI: 70.0 - 91.9) by endoscopist B. The inter-observer agreement, Kappa statistic = 0.68 (95 % CI: 0.51 - 0.89) was good. Conclusion: Fourth-generation endocytoscopy appears to aid in the diagnosis of early gastric cancer, particularly well-differentiated adenocarcinomas, due to its good diagnostic accuracy and identification of the "enlarged nuclear sign," and deserves further evaluation in future studies.