Magnifying endoscopy with narrow-band imaging is more accurate for determination of horizontal extent of early gastric cancers than chromoendoscopy

Advanced Diagnostic and Therapeutic Endoscopy for Early Gastric Cancer

Endoscopy is mandatory to detect early gastric cancer (EGC). When considering the cost-effectiveness of the endoscopic screening of EGC, risk stratification by combining serum pepsinogen values and anti-H. pylori IgG antibody values is very promising. After the detection of suspicious lesions of EGC, a detailed observation using magnifying endoscopy with band-limited light is necessary, which reveals an irregular microsurface and/or an irregular microvascular pattern with demarcation lines in the case of cancerous lesions. Endocytoscopy enables us to make an in vivo histological diagnosis. In terms of the indications for endoscopic resection, the likelihood of lymph node metastasis and technical difficulties in en bloc resection is considered, and they are divided into absolute, expanded, and relative indications. Endoscopic mucosal resection and endoscopic submucosal dissection are the main treatment modalities nowadays. After endoscopic resection, curability is evaluated histologically as endoscopic curability (eCura) A, B, and C (C-1 and C-2). Recent evidence suggests that the outcomes of endoscopic resection for many EGCs are comparable to those of gastrectomy and that endoscopic resection is the gold standard for node-negative early gastric cancers. Personalized medicine is also being developed to overcome the unmet needs in treatments of EGC, for example the further expansion of indications and newer resection techniques, such as full-thickness resection.

Preoperative H. pylori Eradication Therapy Facilitates Precise Delineation in Early Gastric Cancer with Current H. pylori Infection

INTRODUCTION

Early gastric cancer with current Helicobacter pylori infection (HpC-EGC) is common, but it is still unclear whether H. pylori eradication therapy (Hp-ET) or endoscopic submucosal dissection (ESD) should be performed first. We evaluated Hp-ETs short-term effects on horizontal boundary delineations of HpC-EGC in ESD.

METHODS

Prospectively enrolled HpC-EGC patients were randomly assigned to eradication or control groups. Operation scopes of HpC-EGC lesions were delineated with marking dots at 5 mm out of the endoscopic demarcation line by an independent endoscopist, unaware of eradication status, before formal circumferential incision. As representatives, precise delineation rate, the shortest distance of all marking dots to the pathological demarcation line in all slices of one intact resected specimen (Dmin), and negative marking dot specimen rate were examined.

RESULTS

Twenty-three HpC-EGC patients (25 lesions) were allocated to eradication group and 26 patients (27 lesions) were allocated to the control group with similar eradication success rates and all were differentiated type. With improving background mucosa inflammation after Hp-ET and similar gastritis-like epithelium rates, 10 lesions (40.0%) in the eradication group were of precise delineation compared to control group with 2 lesions (7.4%) (relative risk = 5.40, 95% CI 1.31-22.28). Dmin of eradication and control groups were 4.17 ± 2.52 mm and 2.67 ± 2.30 mm (p = 0.029), accompanied by 4 (14.8%) and none (0.0%) specimens that exhibited positive marking dots (p = 0.11), respectively.

CONCLUSION

For HpC-EGC patients, administrating eradication medication before ESD is beneficial for the precise delineation of lesions and reducing the risk of positive horizontal resection margins.

Recent advances in endoscopic management of gastric neoplasms

The development and clinical application of new diagnostic endoscopic technologies such as endoscopic ultrasonography with biopsy, magnification endoscopy, and narrow-band imaging, more recently supplemented by artificial intelligence, have enabled wider recognition and detection of various gastric neoplasms including early gastric cancer (EGC) and subepithelial tumors, such as gastrointestinal stromal tumors and neuroendocrine tumors. Over the last decade, the evolution of novel advanced therapeutic endoscopic techniques, such as endoscopic mucosal resection, endoscopic submucosal dissection, endoscopic full-thickness resection, and submucosal tunneling endoscopic resection, along with the advent of a broad array of endoscopic accessories, has provided a promising and yet less invasive strategy for treating gastric neoplasms with the advantage of a reduced need for gastric surgery. Thus, the management algorithms of various gastric tumors in a defined subset of the patient population at low risk of lymph node metastasis and amenable to endoscopic resection, may require revision considering upcoming data given the high success rate of en bloc resection by experienced endoscopists. Moreover, endoscopic surveillance protocols for precancerous gastric lesions will continue to be refined by systematic reviews and meta-analyses of further research. However, the lack of familiarity with subtle endoscopic changes associated with EGC, as well as longer procedural time, evolving resection techniques and tools, a steep learning curve of such high-risk procedures, and lack of coding are issues that do not appeal to many gastroenterologists in the field. This review summarizes recent advances in the endoscopic management of gastric neoplasms, with special emphasis on diagnostic and therapeutic methods and their future prospects.

Comparison Trial between I-SCAN-Optical Enhancement and Chromoendoscopy for Evaluating the Horizontal Margins of Gastric Epithelial Neoplasms

Background/Aims

Endoscopic submucosal dissection is a widely used treatment for gastric epithelial neoplasms. Accurate delineation of the horizontal margins is necessary for the complete resection of gastric epithelial neoplasms. Recently, image-enhanced endoscopy has been used to evaluate horizontal margins of gastric epithelial neoplasms. The aim of this study was to investigate whether I-SCAN-optical enhancement (I-SCAN-OE) is superior to chromoendoscopy in evaluating the horizontal margin of gastric epithelial neoplasms.

Methods

This was a multicenter, prospective, and randomized trial. The participants were divided into two groups: I-SCAN-OE and chromoendoscopy. For both groups, we first evaluated the horizontal margins of early gastric cancer or high-grade dysplasia using white-light imaging, and then evaluated, the horizontal margins using I-SCAN-OE or chromoendoscopy. We devised a unique scoring method based on the pathological results obtained after endoscopic submucosal dissection to accurately evaluate the horizontal margins of gastric epithelial neoplasms. The delineation scores of both groups were compared, as were the ratios of positive/negative horizontal margins.

Results

In total, 124 patients were evaluated for gastric epithelial neoplasms, of whom 112 were enrolled in the study. A total of 112 patients participated in the study, and 56 were assigned to each group (1:1). There was no statistically significant difference in the delineation scores between the groups (chromoendoscopy, 7.80±1.94; I-SCAN-OE, 8.23±2.24; p=0.342).

Conclusions

I-SCAN-OE did not show superiority over chromoendoscopy in delineating horizontal margins of gastric epithelial neoplasms.

Clinical outcome of the delineation-without-negative-biopsy strategy in magnifying image-enhanced endoscopy for identifying the extent of differentiated-type early gastric cancer

BACKGROUND

The histologic evaluation of biopsy samples collected from the surrounding mucosa has conventionally been used to determine the horizontal extent of early gastric cancer. Recently, optical delineation using magnifying image-enhanced endoscopy (IEE) has been considered an alternative method to histologic evaluation. This study aimed to assess the clinical outcome and efficacy of this method in identifying cancer margins.

METHODS

Overall, 921 patients with 1018 differentiated-type early gastric tumors who underwent endoscopic submucosal dissection (ESD) were examined. Before ESD, the lesions were classified based on whether they have clear or unclear margins on magnifying IEE. When the lesions had clear margins, the marking dots were placed outside the margins without a negative biopsy. Successful delineation was defined as lesions with clear margins and accurate delineation based on histopathological examination. The primary outcome was the accuracy of optical delineation without a negative biopsy compared with histopathological diagnosis. Moreover, the clinicopathological factors associated with an unsuccessful delineation were assessed.

RESULTS

Of 1018 lesions, 820 had a clear margin and 198 an unclear margin. Of 820 lesions with a clear margin, 817 and 3 had an accurate and inaccurate delineation, respectively, according to the histological examination. Accordingly, the accuracy rate of optical delineation was 99.6% (817/820). The significant independent factors associated with an unsuccessful delineation were absence of Helicobacter pylori infection after eradication, tumor size > 20 mm, and moderate differentiation.

CONCLUSIONS

Optical delineation may be an alternative method to histological evaluation in lesions with a clear margin on magnifying IEE.

Endoscopic diagnosis of early gastric cancer

Background: Among the types of gastric cancer, the proportion of early gastric cancer has shown a steady increase because the national screening programs have been conducted in Korea. Accordingly, the paradigm shift of the treatment procedure from surgical gastrectomy to endoscopic resection for selected early gastric cancer has accelerated recently. For successful treatment of early gastric cancer, early detection is essential to accurately predict the histological type, depth of invasion, and horizontal margins of the tumor.Current Concepts: The diagnosis of early gastric cancer and selection of treatment procedures comprises the following steps: (1) presence diagnosis, (2) qualitative diagnosis, and (3) quantitative diagnosis. Presently, early gastric cancer diagnosis is based on the endoscopic detection of a demarcated lesion and irregularity of the mucosal surface or color pattern. If a lesion is diagnosed as early gastric cancer, qualitative and quantitative diagnostic processes should be conducted. Qualitative diagnosis predicts the histological type (differentiated vs. undifferentiated), whereas quantitative diagnosis predicts the invasion depth and horizontal margins of the lesion. The diagnostic processes are based on the macroscopic morphology and color of the lesion, while sometimes using chromoendoscopy, image-enhanced endoscopy, and magnifying endoscopy.Discussion and Conclusion: If gastric cancer is detected at an early stage, most cases can be treated only by endoscopic resection. Therefore, endoscopists should have systematic knowledge regarding the findings of early gastric cancer for timely detection and appropriate selection of the treatment procedure.

Efficacy of a Third-Generation High-Vision Ultrathin Endoscope for Evaluating Gastric Atrophy and Intestinal Metaplasia in Helicobacter pylori-Eradicated Patients

Background: Image-enhanced endoscopy methods such as narrow-band imaging (NBI) are advantageous over white-light imaging (WLI) for detecting gastric atrophy, intestinal metaplasia, and cancer. Although new third-generation high-vision ultrathin endoscopes improve image quality and resolution over second-generation endoscopes, it is unclear whether the former also enhances color differences surrounding atrophy and intestinal metaplasia for endoscopic detection. We compared the efficacy of a new third-generation ultrathin endoscope and an older second-generation endoscope. Methods: We enrolled 50 Helicobacter pylori-eradicated patients who underwent transnasal endoscopy with a second-generation and third-generation endoscope (GIF-290N and GIF-1200N, respectively) in our retrospective study. Color differences based on the International Commission on Illumination 1976 (L*, a*, b*) color space were compared between second-generation and third-generation high-vision endoscopes. Results: Color differences surrounding atrophy produced by NBI on the GIF-1200N endoscope were significantly greater than those on GIF-290N (19.2 ± 8.5 vs. 14.4 ± 6.2, p = 0.001). In contrast, color differences surrounding intestinal metaplasia using both WLI and NBI were similar on GIF-1200N and GIF-290N endoscopes. NBI was advantageous over WLI for detecting intestinal metaplasia on both endoscopes. Conclusions: NBI using a third-generation ultrathin endoscope produced significantly greater color differences surrounding atrophy and intestinal metaplasia in H. pylori-eradicated patients compared with WLI.

The impact of face shields on the quality of gastrointestinal endoscopy during the COVID-19 pandemic

Background

Coronavirus disease 2019 (COVID-19) has become a global pandemic, with healthcare workers at a high risk of exposure. During this pandemic, endoscopists must wear personal protective equipment (PPE), including face shields, to prevent COVID-19 transmission; however, few studies have reported the impact of face shields on the quality of gastrointestinal (GI) endoscopy. We aimed to determine whether the use of PPE, including face shields, affected the quality of GI endoscopy during the COVID-19 pandemic.

Methods

The medical records of patients who had undergone screening or surveillance colonoscopy and gastric endoscopic submucosal dissection (ESD) at Dong-A University Hospital between June 2020 and March 2021 were retrospectively reviewed. Endoscopists wore isolation gowns, disposable gloves, and KF94 masks from June 2020 to October 2020. From November 2020, endoscopists also wore face shields. We compared GI endoscopy quality indicators between the first five months (no face shields) and the second five months (with face shields). In the non-face shield and face shield groups, we calculated the overall adenoma detection rates (ADRs), polyp detection rate (PDR), sessile serrated lesion detection rate (SSLDR), advanced neoplasia detection rate (ANDR), complete resection rate (CRR), number of polyps and/or adenomas per colonoscopy, and gastric ESD procedure time.

Results

In total, 1359 study patients had undergone screening or surveillance colonoscopy (face shield group, n = 679; non-face shield group, n = 680). No statistically significant between-group differences were observed (PDR, 49.04 vs. 52.50%, p = 0.202; ADR, 38.59 vs. 38.97%, p = 0.884; SSPDR, 1.91 vs. 1.32%, p = 0.388; ANDR, 3.98 vs. 3.97%, p = 0.991, respectively). No difference was found in colonoscopy quality indicators between patients examined by experienced and trainee endoscopists with and without face shields. Of 144 study patients who had undergone gastric ESD for gastric neoplasms, there were 72 patients in each group. No statistically significant differences were found in the CRR (94.44 vs 93.05%, p = 1.000) and procedure times (19.22 ± 9.33 vs. 19.03 ± 11.49, p = 0.911).

Conclusions

Wearing face shields during the COVID-19 pandemic did not affect the quality indicators for GI endoscopy.

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.

Diagnostic Ability of Magnifying Narrow-Band Imaging for the Extent of Early Gastric Cancer: A Systematic Review and Meta-Analysis

Background

Accurate delineation of tumor margin is essential for complete resection of early gastric cancer (EGC). The objective of this study is to assess the performance of magnifying endoscopy with narrow-band imaging (ME-NBI) for the accurate demarcation of EGC margins.

Methods

We searched PubMed, EMBASE, Web of Science, and Cochrane Library databases up to March 2020 to identify eligible studies. The diagnostic accuracy of ME-NBI for EGC margins was calculated, and subgroup analyses were performed based on tumor size, depth of tumor invasion, tumor-occupied site, macroscopic type, histological type, Helicobacter pylori (H. pylori), and endoscopists' experience. Besides, we also evaluated the negative and positive resection rates of the horizontal margin (HM) of EGC after endoscopic submucosal dissection (ESD) and surgery.

Results

Ten studies comprising 1018 lesions were eligible in the databases. The diagnostic accuracy of ME-NBI for the demarcation of EGC margins was 92.4% (95% confidence interval (CI): 86.7%-96.8%). According to ME-NBI subgroup analyses, the rate of accurate evaluation of EGC margins was not associated with H. pylori infection status, tumor size, depth of tumor invasion, tumor-occupied site, macroscopic type, histological type, and endoscopists' experience, and no statistical differences were found in subgroup analyses. Moreover, the negative and positive resection rates of HM after ESD and surgery were 97.4% (95% CI: 92.1%-100%) and 2.6% (95% CI: 0.02%-7.9%), respectively.

Conclusions

ME-NBI enables a reliable delineation of the extent of EGC.

Peroral Cholangioscopy-Guided Forceps Mapping Biopsy for Evaluation of the Lateral Extension of Biliary Tract Cancer

Background: Peroral cholangioscopy (POCS)-guided forceps mapping biopsy (FMB) is a method for the accurate preoperative identification of the extent of the disease of biliary tract cancer (BTC). However, the diagnostic value of POCS-FMB is still uncertain. Objectives: We evaluated the diagnostic utility of POCS-FMB for the identification of lateral extension—superficial intraductal spread longitudinally and continuously from the main lesion—of BTC. Methods: In the retrospective study, patients who received POCS-FMB and surgery for curative resection of BTC between September 2016 and August 2019 at our medical institution were enrolled. The diagnostic accuracy of POCS-FMB for the identification of lateral extension of BTC was evaluated. Furthermore, we also evaluated the factors affecting the diagnostic accuracy of POCS-FMB. Results: A total of 23 patients with BTC were enrolled, and 24 procedures of POCS-FMB from 96 sites of biliary tracts were performed. The sensitivity, specificity, and accuracy of POCS-FMB were 53.8%, 63.9%, and 63.1%, respectively. In the multivariate logistic regression analyses, the biopsy from the bifurcation of biliary tracts was a significant factor affecting the diagnostic accuracy of POCS-FMB (odds ratio 3.538, 95%; confidence interval 1.151–10.875, p = 0.027). Conclusions: The diagnostic accuracy of POCS-FMB for the identification of lateral extension of BTC was insufficient. The biopsy from the bifurcation of biliary tracts was a positive factor affecting the diagnostic accuracy of POCS-FMB.

Guidelines for endoscopic submucosal dissection and endoscopic mucosal resection for early gastric cancer (second edition)

In response to the rapid and wide acceptance and use of endoscopic treatments for early gastric cancer, the Japan Gastroenterological Endoscopy Society, in collaboration with the Japanese Gastric Cancer Association, produced "Guidelines for Endoscopic Submucosal Dissection and Endoscopic Mucosal Resection for Early Gastric Cancer" in 2014, as a set of basic guidelines in accordance with the principles of evidence-based medicine. At the time, a number of statements had to be established by consensus (the lowest evidence level), as evidence levels remained low for many specific areas in this field. However, in recent years, the number of well-designed clinical studies has been increasing. Based on new findings, we have issued the revised second edition of the above guidelines that cover the present state of knowledge. These guidelines are divided into the following seven categories: indications, preoperative diagnosis, techniques, evaluation of curability, complications, long-term postoperative surveillance, and histology.

Narrowband imaging with near-focus magnification for discriminating the gastric tumor margin before endoscopic resection: A prospective randomized multicenter trial

BACKGROUND AND AIM

This study investigated the usefulness of near-focus narrowband imaging (NF-NBI) for determining gastric tumor margins compared with indigo carmine chromoendoscopy (ICC) before endoscopic submucosal dissection (ESD).

METHODS

This prospective randomized controlled trial was conducted at seven teaching hospitals in Korea. Patients with gastric adenoma or differentiated adenocarcinoma undergoing ESD were enrolled and randomly assigned to the NF-NBI or ICC group. A marking dot was placed on the most proximal margin of the tumor before ESD. The primary endpoint was delineation accuracy, which was defined as presence of marking dots within 1 mm of the tumor margin under microscopic observation.

RESULTS

A total of 200 patients in the NF-NBI group and 195 patients in the ICC group were included. The delineation accuracy rate was 84.5% in the NF-NBI group and 81.0% in the ICC group (P = 0.44). However, the distance from the marking dot to the margin of the tumor was significantly shorter in the NF-NBI group than in the ICC group (0.8 ± 0.8 vs 1.2 ± 1.3 mm, P < 0.01). Even after adjustment of other clinicopathological factors that are associated with difficulty of tumor delineation, NF-NBI did not show significant association with accurate delineation (odds ratio of 0.86, P = 0.60).

CONCLUSIONS

This prospective multicenter study showed that NF-NBI is not superior to ICC in terms of accurately delineating gastric tumors (NCT02661945).

A deep learning method for delineating early gastric cancer resection margin under chromoendoscopy and white light endoscopy

BACKGROUND

Accurate delineation of cancer margins is critical for endoscopic curative resection. This study aimed to train and validate real-time fully convolutional networks for delineating the resection margin of early gastric cancer (EGC) under indigo carmine chromoendoscopy (CE) or white light endoscopy (WLE), and evaluated its performance and that of magnifying endoscopy with narrow-band imaging (ME-NBI).

METHODS

We collected CE and WLE images of EGC lesions to train fully convolutional networks ENDOANGEL. ENDOANGEL was tested both on stationary images and endoscopic submucosal dissection (ESD) videos. The accuracy and reliability of ENDOANGEL and NBI-dependent delineation were further evaluated by a novel endoscopy-pathology point-to-point marking.

RESULTS

ENDOANGEL had an accuracy of 85.7% in the CE images and 88.9% in the WLE images under an overlap ratio threshold of 0.60 in comparison with the manual markers labeled by the experts. In the ESD videos, the resection margins predicted by ENDOANGEL covered all areas of high-grade intraepithelial neoplasia and cancers. The minimum distance between the margins predicted by ENDOANGEL and the histological cancer boundary was 3.44 ± 1.45 mm which outperformed the resection margin based on ME-NBI.

CONCLUSIONS

ENDOANGEL has the potential to assist endoscopists in delineating the resection extent of EGC under CE or WLE during ESD.

A Novel Technique of Endoscopic Papillectomy with Hybrid Endoscopic Submucosal Dissection for Ampullary Tumors: A Proof-of-Concept Study (with Video)

BACKGROUND

Endoscopic papillectomy (EP) carries a potential risk of procedure-related adverse events and incomplete resection. Since hybrid endoscopic submucosal dissection (ESD) had been established as an alternative option for relatively large and difficult gastrointestinal tumors, we evaluated a novel EP with hybrid ESD (hybrid ESD-EP) for curative safe margin in this proof-of-concept study.

METHODS

A total of eight cases who underwent hybrid ESD-EP between 2018 and 2020 were identified from our prospectively maintained database. Hybrid ESD-EP involved a (sub)circumferential incision with partial submucosal dissection, and subsequent snare resection of ampullary tumors, which was performed by two endoscopists with expertise in ESD or endoscopic retrograde cholangiopancreatography. Demographic data and clinicopathological outcomes were retrospectively evaluated.

RESULTS

En bloc resection was achieved by hybrid ESD-EP in all eight cases, with the median procedure time of 112 (range: 65-170) minutes. The median diameters of the resected specimens and tumors were 18 and 12 mm, respectively. All lateral margins were clear, whereas vertical margin was uncertain in three (38%), resulting in the complete resection rate of 63%. Postoperative bleeding and pancreatitis developed in each one (13%). No tumor recurrence was observed even in those cases with uncertain vertical margin, after a median follow-up of 244 (range, 97-678) days.

CONCLUSIONS

Hybrid ESD-EP seems to be feasible and promising in ensuring the lateral resection margin. However, further investigations, especially to secure the vertical margin and to shorten the procedure time, should be required.

Efficacy and Feasibility of Magnifying Blue Laser Imaging without Biopsy Confirmation for the Diagnosis of the Demarcation of Gastric Tumors: A Randomized Controlled Study

BACKGROUND

Accurate diagnosis of the demarcation line (DL) of gastric tumors is essential for curative complete resection by endoscopic submucosal dissection (ESD). It is controversial to perform only magnifying endoscopy for diagnosing the DL of gastric tumors prior to ESD. This study aimed to evaluate the diagnostic accuracy for the DL of gastric adenomas and well-differentiated adenocarcinomas using only magnifying blue laser imaging (M-BLI) compared with that using both M-BLI and biopsy confirmation.

METHODS

In this prospective, single-center study, 96 well-differentiated adenocarcinomas and 32 gastric adenomas were enrolled between July 2015 and December 2016. A total of 122 lesions with a clear DL on M-BLI were randomly allocated to undergo M-BLI only (the M-BLI group) or M-BLI with biopsy confirmation (the M-BLI-BC group), performed as biopsies in 4 directions from noncancerous tissues ≈ 5 mm outside the lesion before ESD. The primary end point was to clarify the noninferiority of M-BLI without biopsy confirmation compared with that with biopsy confirmation, in terms of the diagnostic accuracy and complete resection.

RESULTS

There were no significant differences in sex, median age, color, circumference, macroscopic type, biopsy-based diagnosis, and Helicobacter pylori infection between the 2 groups. The diagnostic accuracy for the DL was 100 and 95.0% and the complete resection was 100 and 100% in the M-BLI and M-BLI-BC groups, respectively.

CONCLUSION

The diagnostic ability of M-BLI is excellent in diagnosing the demarcation of gastric adenoma and well-differentiated adenocarcinoma. Biopsy confirmation is not needed for these lesions with a clear DL by M-BLI.

Clinical applicability of gastroscopy with narrow-band imaging for the diagnosis of Helicobacter pylori gastritis, precancerous gastric lesion, and neoplasia

Premalignant gastric lesions such as atrophic gastritis and intestinal metaplasia frequently occur in subjects with long-term Helicobacter pylori (H. pylori) infection. The regular arrangement of collecting venules (RAC) is seen in the normal gastric corpus, whereas mucosal swelling and redness without RAC are observed in H. pylori-infected mucosa. Despite successful H. pylori eradication, the presence of atrophic gastritis and/or gastric intestinal metaplasia (GIM) is a risk factor for gastric cancer. With the development of advanced imaging technologies, recent studies have reported the usefulness of narrow-band imaging (NBI) for endoscopic diagnosis of atrophic gastritis and GIM. Using NBI endoscopy with magnification (M-NBI), atrophic gastritis is presented as irregular coiled microvessels and loss of gastric pits. Typical M-NBI endoscopic findings of GIM are a light blue crest and a white opaque substance. Based on the microvascular patterns, fine network, core vascular, and unclear patterns are useful for predicting gastric dysplasia in polypoid lesions. For diagnosis of early gastric cancer (EGC), a systematic classification using M-NBI endoscopy has been proposed on the basis of the presence of a demarcation line and an irregular microvascular/microsurface pattern. Furthermore, M-NBI endoscopy has been found to be more accurate for determining the horizontal margin of EGC compared to conventional endoscopy. In this review, we present up-to-date results on the clinical usefulness of gastroscopy with NBI for the diagnosis of H. pylori gastritis, precancerous gastric lesion, and neoplasia.

Guidelines for endoscopic diagnosis of early gastric cancer

The Japan Gastroenterological Endoscopy Society developed the Guideline for Endoscopic Diagnosis of Early Gastric Cancer based on scientific methods. Endoscopy for the diagnosis of early gastric cancer has been acknowledged as a useful and highly precise examination, and its use has become increasingly more common in recent years. However, the level of evidence in this field is low, and it is often necessary to determine recommendations based on expert consensus only. This clinical practice guideline consists of the following sections to provide the current guideline: [I] Risk stratification of gastric cancer before endoscopic examination, [II] Detection of early gastric cancer, [III] Qualitative diagnosis of early gastric cancer, [IV] Diagnosis to choose the therapeutic strategy for gastric cancer, [V] Risk stratification after endoscopic examination, and [VI] Surveillance of early gastric cancer.

Usefulness of Demarcation of Differentiated-Type Early Gastric Cancers after Helicobacter pylori Eradication by Magnifying Endoscopy with Narrow-Band Imaging

BACKGROUND/AIMS

Early gastric cancer after Helicobacter pylori (Hp) eradication is difficult to demarcate. We used the vessel plus surface classification system (VSCS) to determine whether magnifying endoscopy with narrow-band imaging (ME-NBI) could demarcate differentiated-type early gastric cancers after Hp eradication, and to identify causes of an unclear demarcation line (DL).

METHODS

Among 100 lesions of differentiated-type early gastric cancer resected endoscopically, 34 lesions in the Hp-eradicated group and 66 in the Hp-infected group were retrospectively compared. Clinicopathological factors and ME-NBI findings, including the presence or absence of the DL, were examined. Histopathologically, histological gastritis, the surface structure at the tumor border, well-differentiated adenocarcinoma with low-grade atypia (tub1-low), and non-neoplastic epithelium (NE) coverage rate on the tumor surface and at the tumor border were evaluated.

RESULTS

DL (-) cases were more frequent in the Hp-eradicated group (11.8%, 4/34) than in the Hp-infected group (1.5%, 1/66; p < 0.05). The Hp-eradicated group had a higher NE coverage rate than the Hp-infected group (p < 0.05). All DL (-) cases had tub1-low or NE at the tumor border.

CONCLUSION

ME-NBI with VSCS can identify the DL in most patients (88.2%) with differentiated-type early gastric cancer after Hp eradication.

Usefulness of Narrow-Band Imaging in Endoscopic Submucosal Dissection of the Stomach

There have been many advances in endoscopic imaging technologies. Magnifying endoscopy with narrow-band imaging is an innovative optical technology that enables the precise discrimination of structural changes on the mucosal surface. Several studies have demonstrated its usefulness and superiority for tumor detection and differential diagnosis in the stomach as compared with conventional endoscopy. Furthermore, magnifying endoscopy with narrow-band imaging has the potential to predict the invasion depth and tumor margins during gastric endoscopic submucosal dissection. Classifications of the findings of magnifying endoscopy with narrow-band imaging based on microvascular and pit patterns have been proposed and have shown excellent correlations with invasion depth confirmed by microscopy. In terms of tumor margin prediction, magnifying endoscopy with narrow-band imaging offers superior delineation of gastric tumor margins compared with traditional chromoendoscopy with indigo carmine. The limitations of narrow-band imaging, such as the need for considerable training, long procedure time, and lack of studies about its usefulness in undifferentiated cancer, should be resolved to confirm its value as a complementary method to endoscopic submucosal dissection. However, the role of magnifying endoscopy with narrow-band imaging is expected to increase steadily with the increasing use of endoscopic submucosal dissection for the treatment of gastric tumors.

Computer-aided diagnosis for identifying and delineating early gastric cancers in magnifying narrow-band imaging

BACKGROUND AND AIMS

Magnifying narrow-band imaging (M-NBI) is important in the diagnosis of early gastric cancers (EGCs) but requires expertise to master. We developed a computer-aided diagnosis (CADx) system to assist endoscopists in identifying and delineating EGCs.

METHODS

We retrospectively collected and randomly selected 66 EGC M-NBI images and 60 non-cancer M-NBI images into a training set and 61 EGC M-NBI images and 20 non-cancer M-NBI images into a test set. After preprocessing and partition, we determined 8 gray-level co-occurrence matrix (GLCM) features for each partitioned 40 × 40 pixel block and calculated a coefficient of variation of 8 GLCM feature vectors. We then trained a support vector machine (SVM_Lv1) based on variation vectors from the training set and examined in the test set. Furthermore, we collected 2 determined P and Q GLCM feature vectors from cancerous image blocks containing irregular microvessels from the training set, and we trained another SVM (SVM_Lv2) to delineate cancerous blocks, which were compared with expert-delineated areas for area concordance.

RESULTS

The diagnostic performance revealed accuracy of 96.3%, precision (positive predictive value [PPV]) of 98.3%, recall (sensitivity) of 96.7%, and specificity of 95%, at a rate of 0.41 ± 0.01 seconds per image. The performance of area concordance, on a block basis, demonstrated accuracy of 73.8% ± 10.9%, precision (PPV) of 75.3% ± 20.9%, recall (sensitivity) of 65.5% ± 19.9%, and specificity of 80.8% ± 17.1%, at a rate of 0.49 ± 0.04 seconds per image.

CONCLUSIONS

This pilot study demonstrates that our CADx system has great potential in real-time diagnosis and delineation of EGCs in M-NBI images.

[Endoscopic and surgical treatment of early gastric and esophageal carcinoma]

BACKGROUND

The treatment of early gastric (EGC) and esophageal carcinomas (EEC) is an interdisciplinary challenge. The risk of lymph node metastasis (LNM) is the crucial point in choosing the correct treatment option.

OBJECTIVE

This article gives an overview of the current treatment options and provides help in choosing the correct therapy.

METHOD

Current concepts and therapy algorithms are presented on the basis of a literature review and data from our own center.

RESULTS

Endoscopic submucosal dissection (ESD) is recommended for mucosal gastric cancer with good or moderate differentiation (G1,2) without macroscopic ulceration, in elevated type lesions smaller than 2 cm in size or depressed lesions smaller than 1 cm in size. In additional chromoendoscopy should be carried out. The extent of surgical resection is defined by the location of the tumor. A safety margin of at least 3 cm should be applied in distal gastric resections whereas the first line goal in gastrectomy is to achieve an R0 resection. In cN0 tumors a D1 lymphadenectomy (LA) seems to be sufficient. Minimally invasive techniques currently show promising results especially for a subtotal resection. The treatment strategy in EEC differs depending on the tumor entity. Mucosal squamous cell carcinoma with high risk factors (L1,V1) and all cN0 submucosal tumors without the detection of LNM should be referred to primary surgical resection. Early stage cN+ squamous cell carcinomas should be preoperatively treated with chemoradiotherapy. Adenocarcinoma with infiltration of the deeper submucosa (sm2,3) and high-risk sm1 tumors require surgical treatment. The standard operating procedure for EEC is an Ivor Lewis esophagectomy with 2‑field LA preferably performed as a hybrid or by a completely minimally invasive procedure. The procedure of choice in endoscopic resection of EEC is resection with the suck and cut technique.