Magnifying endoscopy with narrow-band imaging achieves superior accuracy in the differential diagnosis of superficial gastric lesions identified with white-light endoscopy: a prospective study

Endoscopic detection and diagnosis of gastric cancer using image-enhanced endoscopy: A systematic review and meta-analysis

OBJECTIVES

We aimed to conduct a systematic review and meta-analysis to assess the value of image-enhanced endoscopy including blue laser imaging (BLI), linked color imaging, narrow-band imaging (NBI), and texture and color enhancement imaging to detect and diagnose gastric cancer (GC) compared to that of white-light imaging (WLI).

METHODS

Studies meeting the inclusion criteria were identified through PubMed, Cochrane Library, and Japan Medical Abstracts Society databases searches. The pooled risk ratio for dichotomous variables was calculated using the random-effects model to assess the GC detection between WLI and image-enhanced endoscopy. A random-effects model was used to calculate the overall diagnostic performance of WLI and magnifying image-enhanced endoscopy for GC.

RESULTS

Sixteen studies met the inclusion criteria. The detection rate of GC was significantly improved in linked color imaging compared with that in WLI (risk ratio, 2.20; 95% confidence interval [CI], 1.39-3.25; p < 0.01) with mild heterogeneity. Magnifying endoscopy with NBI (ME-NBI) obtained a pooled sensitivity, specificity, and area under the summary receiver operating curve of 0.84 (95 % CI, 0.80-0.88), 0.96 (95 % CI, 0.94-0.97), and 0.92, respectively. Similarly, ME-BLI showed a pooled sensitivity, specificity, and area under the curve of 0.81 (95 % CI, 0.77-0.85), 0.85 (95 % CI, 0.82-0.88), and 0.95, respectively. The diagnostic efficacy of ME-NBI/BLI for GC was evidently high compared to that of WLI, However, significant heterogeneity among the NBI studies still existed.

CONCLUSIONS

Our meta-analysis showed a high detection rate for linked color imaging and a high diagnostic performance of ME-NBI/BLI for GC compared to that with WLI.

The West Catching Up With the East: High-Magnification NBI Is Accurate for the Diagnosis of Gastric Neoplasia in a Western Population

BACKGROUND AND AIM

Accurate endoscopic prediction of histology is key to recognition of early gastric neoplasia and selection of appropriate resection techniques. Narrow-band imaging with magnification (M-NBI) has proven to be highly accurate for gastric lesions in eastern countries; however, we sought to examine whether it can be effectively utilized in the west where evidence is scarce.

METHODS

This is an analysis of a prospective database of gastric lesions at a single Australian center from 2009 to 2023. All lesions were assessed endoscopically using M-NBI and a determination made whether the lesion was neoplastic or non-neoplastic, as well as prediction of histological subtype. This was then correlated with final histology.

RESULTS

A total of 232 lesions in 183 patients were included: 135 non-neoplastic and 97 neoplastic lesions. Thirty-five were adenomas, 29 early gastric cancers, and 6 advanced adenocarcinomas. For differentiating neoplastic versus non-neoplastic lesions, M-NBI had a sensitivity of 97.9% (CI 92.6%-99.7%) and specificity of 97.1% (CI 92.7%-99.2%). M-NBI was also highly accurate (97.0%, CI 93.9%-98.8%) for identifying lesions suitable for endoscopic resection. The observed agreement between the M-NBI predicted histology and the final pathology was 91.8% with a derived kappa statistic of 0.87, indicating excellent agreement. Comparatively, prior biopsies had an observed agreement of 40.4% with final histology, with a derived kappa statistic of 0.27.

CONCLUSIONS

M-NBI can be used with a high degree of accuracy in a western population. M-NBI can effectively differentiate neoplastic from non-neoplastic gastric lesions and delineate histological subtypes with superior accuracy to previous biopsies.

Endoscopic and clinicopathological features of early gastric papillary adenocarcinoma

Objectives

Gastric papillary adenocarcinoma (GPA), a well-differentiated gastric adenocarcinoma, is associated with a worse prognosis compared to other differentiated gastric adenocarcinomas. Therefore, there is an urgent need to characterize its endoscopic manifestations for guiding biopsy site selection and achieving accurate diagnosis.

Methods

From January 1, 2016, to December 31, 2022, the data of 46 cases of early gastric papillary adenocarcinoma (EGPA) and 183 cases of early gastric differentiated tubular adenocarcinoma (EGDTA) diagnosed via pathological examination following endoscopic submucosal dissection (ESD) at the Second Hospital of Shandong University were collected. Propensity score matching (PSM) was employed to match 92 EGDTA patients at a ratio of 1:2, serving as the control group. Differences between the two groups were analyzed using multivariable logistic regression. Lastly, the relationship between vessels within epithelial circle (VEC) structures in EGPA and the degree of malignancy was assessed.

Results

Compared with EGDTA, EGPA was more likely to infiltrate the submucosa, more frequently associated with poorly differentiated cancer components, and more prone to invading lymphatic and blood vessels. EGPA was primarily located in the lower stomach and manifested as a uniformly elevated pattern under endoscopy, while VEC structural positivity could be visualized under ME-NBI. Moreover, EGPA lesions had larger diameters and were characterized by high expression of gastric mucins, namely MUC5AC and MUC6. When EGPA infiltrated the submucosa or contained poorly differentiated cancer components, the VEC structures were smaller.

Conclusions

The present study demonstrated that EGPA exhibits a higher degree of malignancy. Endoscopic findings of a raised lesion with a uniform color under endoscopy and the presence of VEC structures under ME-NBI suggest a high possibility of EGPA. Moreover, smaller VEC structures were associated with a higher degree of malignancy, which may assist in guiding the selection of biopsy sites under endoscopy.

The role of magnification endoscopy in the early diagnosis of gastric signet ring cell carcinoma

We present the case of a 67-year-old woman referred to our outpatient clinic presenting dyspepsia. Gastroscopy was performed, showing antral gastritis. Random biopsies were taken, being positive for poorly differentiated Lauren's diffuse gastric adenocarcinoma. Narrow-band imaging gastroscopy was performed, combining random and targeted biopsies, with negative results. The study was completed with echoendoscopy and thoraco-abdominal-pelvic CT scan, showing no relevant pathological findings. Control endoscopic was performed after 12 months, showing no macroscopic lesions. Random biopsies were repeated, being positive for diffuse gastric adenocarcinoma. Gastroscopy with conventional chromoendoscopy was performed, showing a completely flat area of approximately 2cm of diameter in the body-antrum junction, in the greater curvature; it was well delimited and no indigo carmine staining was observed (Figure 1). Electronic magnification was performed, showing disruption of the crypt pattern and aberrant neovessels (Figures 2 and 3). Targeted biopsies were taken, being positive for poorly differentiated gastric adenocarcinoma. The case was discussed in a multidisciplinary session and subtotal gastrectomy was performed. Magnification endoscopy offers a better performance diagnosing early gastric cancer than white light endoscopy. [1] It allows the identification of patterns that can predict malignancy, such as distortion of the mucosal glandular pattern or aberrant proliferation of neovessels. [2] Once the diagnosis has been established, assessing the depth of invasion has great clinical relevance, as it guides therapeutic decisions. Works such as that of Zhou et al. [3] underline the usefulness of linear echoendoscopy in this process.

Risk factors of missed early gastric cancer in endoscopic resected population: a retrospective, case-control study

BACKGROUND

Missed early gastric cancer (MEGC) is prevalent during esophagogastroduodenoscopy (EGD), which is the first-line recommended strategy for detecting early gastric cancer (EGC). Hence, we explored the risk factors for MEGC and different types of MEGC, based on the endoscopic resected population.

METHODS

This retrospective, case-control study was conducted at Nanjing Drum Tower Hospital (NJDTH). We included patients who were diagnosed with EGC during screening EGD, underwent endoscopic resection, and were confirmed by postoperative pathology at the NJDTH from January 2014 to December 2021, and classified them into different types according to the different root causes of misses. Univariable, multivariable, subgroup and propensity score analyses were used to explore the risk factors for MEGC and different types of MEGC.

RESULTS

A total of 447 patients, comprising 345 with initially detected early gastric cancer (IDEGC) and 102 with MEGC, were included in this study. Larger size (≥ 1 cm) (OR 0.45, 95% CI 0.27-0.74, P = 0.002) and invasion depth of submucosa (OR 0.26, 95% CI 0.10-0.69, P = 0.007) were negatively associated with MEGC. Use of sedation (OR 0.32, 95% CI 0.20-0.52, P < 0.001) and longer observation time (OR 0.60, 95% CI 0.37-0.96, P = 0.034) exhibited protective effect on MEGC.

CONCLUSIONS

Smaller and more superficial EGC lesions are more susceptible to misdiagnosis. The use of sedation and prolonged observation time during EGD could help reduce the occurrence of MEGC.

Effect of Helicobacter pylori eradication evaluated using magnifying endoscopy with narrow-band imaging in mixed-type early gastric Cancer

BACKGROUND

The effect of Helicobacter pylori (H.pylori) eradication therapy on mixed-histological-type gastric cancer remains unclear. This study aimed to clarify the effect of H. pylori eradication therapy on mixed-histological-type early gastric cancer using endoscopic and histological findings.

METHODS

This single-center, retrospective study included patients with mixed-histological-type gastric cancer who underwent endoscopic submucosal dissection at the Cancer Institute Hospital. We compared detailed magnifying endoscopy with narrow-band imaging findings between eradicated and non-eradicated groups of patients with differentiated-type- and undifferentiated-type-predominant cancers. Subsequently, we performed histological evaluations of the non-cancerous epithelium covering differentiated-type components.

RESULTS

A total of 124 patients with mixed-type early gastric cancer were enrolled (eradicated group: 62 differentiated-type-predominant cancer patients and 8 undifferentiated-type-predominant cancer patients; non-eradication group: 40 differentiated-type-predominant cancer patients and 14 undifferentiated-type-predominant cancer patients). Regarding differentiated-type-predominant cancer, differentiated-type findings were detected in all patients in eradicated and non-eradicated groups. The difference in the detection rate of undifferentiated-type findings between both groups was not significant in differentiated-type-predominant cancer patients. In differentiated-type-predominant cancers, the percentage of non-cancerous epithelium covering differentiated-type components was higher in the eradicated group than in the non-eradicated group (median: 60% vs. 40%, p < 0.001).

CONCLUSIONS

Although the pathological findings of differentiated-type-predominant cancer were affected by H. pylori eradication, eradication did not affect the diagnosis of differentiated-type-predominant early gastric cancer using magnifying endoscopy with narrow-band imaging. ME-NBI is useful for the early detection of D-MIX EGCs and diagnosis of histological types during endoscopy, regardless of whether H. pylori eradication therapy has been administered.

Magnifying image-enhanced endoscopy-only mode boosted early cancer diagnostic efficiency: a multicenter randomized controlled trial

BACKGROUND AND AIMS

Magnifying image-enhanced endoscopy (MIEE) is an advanced endoscopy with image enhancement and magnification used in preoperative examination. However, its impact on the detection rate is unknown.

METHODS

We conducted an open-label, randomized, parallel (1:1:1), controlled trial in 6 hospitals in China. Patients were recruited between February 14, 2022 and July 30, 2022. Eligible patients were aged ≥18 years and undergoing gastroscopy in outpatient departments. Participants were randomly assigned to the MIEE-only mode (o-MIEE) group, white-light endoscopy-only mode (o-WLE) group, and MIEE when necessary mode (n-MIEE) group (initial WLE followed by switching to another endoscope with MIEE if necessary). Biopsy sampling of suspicious lesions of the lesser curvature of the gastric antrum was performed. Primary and secondary aims were to compare detection rates and positive predictive value (PPV) of early cancer and precancerous lesions in these 3 modes, respectively.

RESULTS

A total of 5100 recruited patients were randomly assigned to the o-MIEE (n = 1700), o-WLE (n = 1700), and n-MIEE (n = 1700) groups. In the o-MIEE, o-WLE, and n-MIEE groups, 29 (1.51%; 95% confidence interval [CI], 1.05-2.16), 4 (.21%; 95% CI, .08-.54), and 8 (.43%; 95% CI, .22-.85) early cancers were found, respectively (P < .001). The PPV for early cancer was higher in the o-MIEE group compared with the o-WLE and n-MIEE groups (63.04%, 33.33%, and 38.1%, respectively; P = .062). The same trend was seen for precancerous lesions (36.67%, 10.00%, and 21.74%, respectively).

CONCLUSIONS

The o-MIEE mode resulted in a significant improvement in diagnosing early upper GI cancer and precancerous lesions; thus, it could be used for opportunistic screening. (Clinical trial registration number: ChiCTR2200064174.).

The features of gastric epithelial reactive hyperplastic lesions under magnifying endoscopy combined with narrow-band imaging

BACKGROUND AND PURPOSE

Gastric reactive hyperplasia (RH) is a common benign lesion of the gastric mucosa that can be resolved by conservative treatment without endoscopic intervention. Some RH lesions are indistinguishable from low-grade intraepithelial neoplasia (LGIN) lesions of gastric mucosa under endoscopy. The aim of this study was to investigate the morphological features of RH lesions under magnifying endoscopy combined with narrow-band imaging (ME-NBI).

METHODS

A retrospective study of 653 patients with superficial suspicious lesions of gastric mucosa was performed. According to the pathological results of biopsies, the final included lesions were divided into the RH group (n = 88) and LGIN group (n = 138). We analysed the microvascular and microsurface patterns of these lesions under ME-NBI, extracted the most significant combination of endoscopic features of RH lesions, and evaluated their diagnostic performance.

RESULTS

ME-NBI characteristics that could distinguish RH lesions from LGIN lesions after univariate analysis were included in multivariate logistic regression. The results showed that ten characteristics, including intervening part (IP) length homogeneity, type III gastric pit pattern and homogeneity of marginal crypt epithelium (MCE), were statistically significant. Receiver operating characteristic (ROC) analysis showed that the triad of these features was the best combination for diagnosing RH lesions with an AUC of 0.886 (95% confidence interval; 0.842-0.929), the sensitivity of 85.5% and specificity of 79.5%.

CONCLUSIONS

The triad of IP length homogeneity, type III pit pattern and MCE homogeneity under ME-NBI helps endoscopists to identify gastric RH lesions, thereby avoiding unnecessary biopsy and repeat endoscopy due to misjudgment of neoplastic lesions.

Targeted labeling with tissue marking dyes guided by magnifying endoscopy of endoscopic submucosal dissection specimen improves the accuracy of endoscopic and histopathological diagnosis of early gastric cancer: a before-after study

BACKGROUND

Although histopathological evaluation after endoscopic submucosal dissection (ESD) is critical to assess the accuracy of endoscopic diagnosis, it is still challenging to perform precise endoscopic to pathological evaluation. We evaluated the importance of tissue marking dye (TMD)-targeted marking for post-ESD specimen guided by magnificent endoscope on histopathological accuracy and endoscopic-to-histopathological reconstruction.

STUDY DESIGN

A total of 81 specimens resected by ESD [43 without TMD marking (N-TMD group), and 38 specimens with TMD-targeted cancerous areas marking guided by post-procedural magnifying endoscopy on resected specimens (TMD group)] between January 31, 2019, and January 31, 2022 at the Renmin Hospital of Wuhan University were included in the study. The baseline characteristics of patients, discrepancies between endoscopic and histopathological diagnosis, and the impact of TMD on histopathological diagnosis and reconstruction were analyzed.

RESULTS

Discrepancies between endoscopic (pre-ESD) and histopathological (post-ESD) diagnosis increased significantly in TMD group (68.4% (26/38) for tumor areas, 26.3% (10/38) for tumor margins, and 26.3% (10/38) for tumor differentiations) when compared with N-TMD group (p < 0.0001). Deeper sections were achieved in all TMD-marked resected lesions and 27.9% (12/43) lesions in the N-TMD group (p < 0.001). More pathological evaluations in TMD group were changed from curative resection to non-curative resection [6/38(15.8%) vs 1/43(2.3%)] compared with N-TMD group (p < 0.0001). TMD-targeted marking also improved the efficiency of histopathological reconstruction on pre-procedural endoscopic images and benefit endoscopists training.

CONCLUSION

TMD-targeted labeling on resected specimens could improve precise endoscopic-to-pathological diagnosis, reconstruction by point-to-point marking and benefit endoscopists training.

Intensive Systematic "Train-the-Trainer" Course as an Effective Strategy to Improve Detection of Early Gastric Cancer: A Multicenter Retrospective Study

BACKGROUND

To improve the diagnosis of early gastric cancer (EGC), a train-the-trainer (TTT) course was developed. This trial aimed to investigate whether TTT courses from trained trainers could improve trainees' EGC detection.

METHODS

In this multi-center, retrospective study, the training was carried out 8 times in one year. Clinical records one year before ("2016"), during ("2017"), and after ("2018") the course were collected. The primary endpoint was the improvement of EGC detection rate after TTT courses.

RESULTS

Twenty-four trainees from 17 hospitals were included in this study. A total of 123,416 esophagogastroduodenoscopy and 65,570 colonoscopy procedures were analyzed. The early gastric cancer detection rate (EDR) was 0.101% in 2016, which significantly increased to 0.338% in 2018 (p = 0.015). The early gastric cancer ratio (ECR, ratio of newly detected EGCs to all newly detected gastric cancers) in 2016 was 8.440%, which consistently increased to 11.853% and 19.778% in 2017 and 2018 (p = 0.006), respectively. In contrast, the advanced gastric cancer detection rate (ADR) was similar before, during, or after the course (p = 0.987). The 3-year EDR, ECR, and ADR in esophageal and colorectal cancer were not significantly different.

CONCLUSIONS

The systematic training course can improve EGC detection rate and may be an effective educational strategy to reduce gastrointestinal cancers mortality.

Diagnosis and segmentation effect of the ME-NBI-based deep learning model on gastric neoplasms in patients with suspected superficial lesions - a multicenter study

Background

Endoscopically visible gastric neoplastic lesions (GNLs), including early gastric cancer and intraepithelial neoplasia, should be accurately diagnosed and promptly treated. However, a high rate of missed diagnosis of GNLs contributes to the potential risk of the progression of gastric cancer. The aim of this study was to develop a deep learning-based computer-aided diagnosis (CAD) system for the diagnosis and segmentation of GNLs under magnifying endoscopy with narrow-band imaging (ME-NBI) in patients with suspected superficial lesions.

Methods

ME-NBI images of patients with GNLs in two centers were retrospectively analysed. Two convolutional neural network (CNN) modules were developed and trained on these images. CNN1 was trained to diagnose GNLs, and CNN2 was trained for segmentation. An additional internal test set and an external test set from another center were used to evaluate the diagnosis and segmentation performance.

Results

CNN1 showed a diagnostic performance with an accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of 90.8%, 92.5%, 89.0%, 89.4% and 92.2%, respectively, and an area under the curve (AUC) of 0.928 in the internal test set. With CNN1 assistance, all endoscopists had a higher accuracy than for an independent diagnosis. The average intersection over union (IOU) between CNN2 and the ground truth was 0.5837, with a precision, recall and the Dice coefficient of 0.776, 0.983 and 0.867, respectively.

Conclusions

This CAD system can be used as an auxiliary tool to diagnose and segment GNLs, assisting endoscopists in more accurately diagnosing GNLs and delineating their extent to improve the positive rate of lesion biopsy and ensure the integrity of endoscopic resection.

Kyoto classification of gastritis, virtual chromoendoscopy and artificial intelligence: Where are we going? What do we need?

Chronic gastritis (CG) is a widespread and frequent disease, mainly caused by Helicobacter pylori infection, which is associated with an increased risk of gastric cancer. Virtual chromoendoscopy improves the endoscopic diagnostic efficacy, which is essential to establish the most appropriate therapy and to enable cancer prevention. Artificial intelligence provides algorithms for the diagnosis of gastritis and, in particular, early gastric cancer, but it is not yet used in practice. Thus, technological innovation, through image resolution and processing, optimizes the diagnosis and management of CG and gastric cancer. The endoscopic Kyoto classification of gastritis improves the diagnosis and management of this disease, but through the analysis of the most recent literature, new algorithms can be proposed.

Automatic captioning of early gastric cancer using magnification endoscopy with narrow-band imaging

BACKGROUND AND AIMS

The detection rate for early gastric cancer (EGC) is unsatisfactory, and mastering the diagnostic skills of magnifying endoscopy with narrow-band imaging (ME-NBI) requires rich expertise and experience. We aimed to develop an EGC captioning model (EGCCap) to automatically describe the visual characteristics of ME-NBI images for endoscopists.

METHODS

ME-NBI images (n = 1886) from 294 cases were enrolled from multiple centers, and corresponding 5658 text data were designed following the simple EGC diagnostic algorithm. An EGCCap was developed using the multiscale meshed-memory transformer. We conducted comprehensive evaluations for EGCCap including the quantitative and quality of performance, generalization, robustness, interpretability, and assistant value analyses. The commonly used metrics were BLEUs, CIDEr, METEOR, ROUGE, SPICE, accuracy, sensitivity, and specificity. Two-sided statistical tests were conducted, and statistical significance was determined when P < .05.

RESULTS

EGCCap acquired satisfying captioning performance by outputting correctly and coherently clinically meaningful sentences in the internal test cohort (BLEU1 = 52.434, CIDEr = 36.734, METEOR = 27.823, ROUGE = 49.949, SPICE = 35.548) and maintained over 80% performance when applied to other centers or corrupted data. The diagnostic ability of endoscopists improved with the assistance of EGCCap, which was especially significant (P < .05) for junior endoscopists. Endoscopists gave EGCCap an average remarkable score of 7.182, showing acceptance of EGCCap.

CONCLUSIONS

EGCCap exhibited promising captioning performance and was proven with satisfying generalization, robustness, and interpretability. Our study showed potential value in aiding and improving the diagnosis of EGC and facilitating the development of automated reporting in the future.

Low-magnification narrow-band imaging for small gastric neoplasm detection on screening endoscopy

Background and Aims

Microsurface patterns of the gastric mucosa can be observed using magnifying narrow-band imaging (M-NBI). However, the efficacy of M-NBI at low-magnification (LM-NBI) screening for detecting small gastric neoplasms is unclear.

Methods

This prospective study was conducted at a single institution. LM-NBI, defined as minimal magnification that could reveal the microsurface pattern of the gastric mucosa, was performed after routine white-light imaging (WLI) observation of the stomach. Depending on the phase in which the neoplastic lesions were initially found, they were divided into the WLI group and the LM-NBI group, and the characteristics of these neoplastic lesions were investigated accordingly.

Results

Sixty-five epithelial lesions (adenomas or noninvasive carcinomas) of 20 mm or less in diameter were identified in this study. Sixteen lesions were detected only with LM-NBI. Smaller lesions were detected using LM-NBI (P = .01). WLI took about 160 to 260 seconds, while LM-NBI required about 70 to 80 seconds. All lesions in the LM-NBI group had a background of map-like redness (n = 5) or atrophic/metaplastic mucosa (n = 11).

Conclusions

LM-NBI was able to detect lesions overlooked by WLI, especially those in areas of map-like redness or atrophic/metaplastic mucosa of the stomach. Approximately one-quarter of newly diagnosed neoplasms were retrieved on routine examination during an extra 1.5 minutes.

Probe-Based Confocal Laser Endomicroscopy versus White-Light Endoscopy with Narrow-Band Imaging for Predicting and Collecting Residual Cancer Tissue in Patients with Gastric Cancer Receiving Chemotherapy

In cases of progression despite chemotherapy, collecting gastric cancer (GC) tissues might be helpful for molecular biology research or the development of new target drugs for treating cases that are refractory to chemotherapy. Chemotherapy, however, may reduce or alter the distribution of GC tissue on the surface, making the detection of GC tissue during upper endoscopy challenging. Probe-based confocal laser endomicroscopy (pCLE) is a new technology that enables histological diagnosis by magnifying the mucous membrane to a microscopic level. Here, we evaluated whether pCLE could increase the yield of endoscopic biopsy for GC compared to white-light endoscopy (WLE) with magnifying narrow-band imaging (M-NBI) in GC patients receiving chemotherapy with its powerful imaging technique. Patients underwent WLE/M-NBI and pCLE for the detection of residual GC for the purpose of response evaluation or clinical trial registration. After WLE/M-NBI and pCLE, each residual GC lesion was biopsied for histological analysis. A total of 23 patients were enrolled between January 2018 and June 2020. Overall, pCLE showed significantly higher sensitivity and negative predictive value than WLE/M-NBI. The accuracy of pCLE was superior to that of WLE/M-NBI. Moreover, pCLE showed better predictive ability for residual GC than WLE/M-NBI, while WLE/M-NBI and pCLE showed inconsistent results. pCLE diagnosed residual GC more accurately than WLE/M-NBI, which resulted in an increased number of GC tissues collected during the endoscopic biopsy.

Gastric Cancer: Emerging Trends in Prevention, Diagnosis, and Treatment

Gastric adenocarcinoma (GC) is the fourth leading cause of global cancer mortality, and the leading infection-associated cancer. Helicobacter pylori is the dominant risk factor for GC and classified as an IARC class I carcinogen. Surveillance of gastric premalignant conditions is now indicated in high-risk patients. Upper endoscopy is the gold standard for GC diagnosis, and image-enhanced endoscopy increases the detection of gastric premalignant conditions and early gastric cancer (EGC). Clinical staging is crucial for treatment approach, defining early gastric cancer, operable locoregional disease, and advanced GC. Endoscopic submucosal dissection is the treatment of choice for most EGC. Targeted therapies are rapidly evolving, based on biomarkers including MSI/dMMR, HER2, and PD-L1. These advancements in surveillance, diagnostic and therapeutic strategies are expected to improve GC survival rates in the near term.

Application of deep learning in the real-time diagnosis of gastric lesion based on magnifying optical enhancement videos

Background and aim

Magnifying image-enhanced endoscopy was demonstrated to have higher diagnostic accuracy than white-light endoscopy. However, differentiating early gastric cancers (EGCs) from benign lesions is difficult for beginners. We aimed to determine whether the computer-aided model for the diagnosis of gastric lesions can be applied to videos rather than still images.

Methods

A total of 719 magnifying optical enhancement images of EGCs, 1,490 optical enhancement images of the benign gastric lesions, and 1,514 images of background mucosa were retrospectively collected to train and develop a computer-aided diagnostic model. Subsequently, 101 video segments and 671 independent images were used for validation, and error frames were labeled to retrain the model. Finally, a total of 117 unaltered full-length videos were utilized to test the model and compared with those diagnostic results made by independent endoscopists.

Results

Except for atrophy combined with intestinal metaplasia (IM) and low-grade neoplasia, the diagnostic accuracy was 0.90 (85/94). The sensitivity, specificity, PLR, NLR, and overall accuracy of the model to distinguish EGC from non-cancerous lesions were 0.91 (48/53), 0.78 (50/64), 4.14, 0.12, and 0.84 (98/117), respectively. No significant difference was observed in the overall diagnostic accuracy between the computer-aided model and experts. A good level of kappa values was found between the model and experts, which meant that the kappa value was 0.63.

Conclusions

The performance of the computer-aided model for the diagnosis of EGC is comparable to that of experts. Magnifying the optical enhancement model alone may not be able to deal with all lesions in the stomach, especially when near the focus on severe atrophy with IM. These results warrant further validation in prospective studies with more patients. A ClinicalTrials.gov registration was obtained (identifier number: NCT04563416).

Clinical Trial Registration

ClinicalTrials.gov, identifier NCT04563416.

Proposal of minimum elements for screening and diagnosis of gastric cancer by an international Delphi consensus

The World Endoscopy Organization Stomach and Duodenal Diseases Committee extracted minimum elements for screening and diagnosis of gastric cancer (GC) in aim to support countries that do not have national guidelines on screening and diagnosis of GC. Current national or international guidelines were collected worldwide and recommendations were classified according to the quality of evidence and were finalized through a modified Delphi method. The minimum elements consist of seven categories: [1] Extraction of high-risk patients of GC before esophagogastroduodenoscopy (EGD), [2] Patients who need surveillance of GC, [3] Method to ensure quality of EGD for detection of GC, [4] Individual GC risk assessment by EGD, [5] Extraction of high-risk patients of GC after EGD [6] Qualitative or differential diagnosis of GC by EGD, and [7] Endoscopic assessment to choose the therapeutic strategy for GC. These minimum elements will be a guide to promote the elimination of GC among countries with a high incidence of GC who lack national guidelines or screening programs.

Removal of Specular Reflection Using Angle Adjustment of Linear Polarized Filter in Medical Imaging Diagnosis

The biggest problem in imaging medicine is the occurrence of light reflection in the imaging process for lesion diagnosis. The formation of light reflection obscures the diagnostic field of the lesion and interferes with the correct diagnosis of the observer. The existing method has the inconvenience of performing a diagnosis in a state in which light reflection is suppressed by adjusting the direction angle of the camera. This paper proposes a method for rotating a linear polarization filter to remove light reflection in a diagnostic imaging camera. Vertical polarization and horizontal polarization are controlled through the rotation of the filter, and the polarization is adjusted to horizontal polarization. The rotation angle of the filter for horizontal polarization control will be 90°, and the vertical and horizontal polarization waves induce a 90° difference from each other. In this study, light reflection can be effectively removed during the imaging process, and light reflection removal can secure the field of view of the lesion. The removal of light reflection can help the observer’s accurate diagnosis, and these results are expected to be highly reliable and commercialized for direct application in the field of diagnostic medicine.

Endoscopic Classifications of Early Gastric Cancer: A Literature Review

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.

Gastric neoplasms in patients with familial adenomatous polyposis: endoscopic and clinicopathologic features

BACKGROUND AND AIMS

Gastric neoplasms in patients with familial adenomatous polyposis (FAP) occur at a high rate and can cause death. The endoscopic findings of gastric neoplasms in these patients are characteristic but not well recognized. To identify the relevant characteristics to enable early detection, we retrospectively investigated endoscopic findings of gastric neoplasms in patients with FAP and then compared the clinical, histopathologic, and genetic features among subgroups.

METHODS

Of 234 patients with 171 pedigrees at 2 institutes, 56 cases (24%, 133 gastric neoplasms) with 44 pedigrees were examined. Immunostaining was performed for histopathologic evaluation by 1 blinded pathologist. According to the endoscopic findings, gastric neoplasms were divided into 4 types based on location (L: antrum and pylorus, UM: the rest of the stomach) and color (W: white, T: translucent, R: reddish) and their clinicopathologic features examined.

RESULTS

Of the cases, 93% could be classified into a single type. Among histologic phenotypes, high-grade dysplasia was present in 26% (type L), 41% (type UM-W), 0% (type UM-T), and 22% (type UM-R). The immunologic phenotype comprised the gastric type in 69% (93% in Type UM) and the intestinal phenotype, including the mixed type, in 31% (61% in type L). Moreover, 96% of patients had concurrent duodenal neoplasms. Adenomatous polyposis coli gene status was identified in 93% of patients; the pathogenic variant was detected in 98% but did not influence any endoscopic features.

CONCLUSIONS

Gastric neoplasms in patients with FAP were stratified into 4 types according to their endoscopic findings. The endoscopic phenotype was related to the histopathologic phenotype but not to germline variants.

Impact of non-curative endoscopic submucosal dissection on short- and long-term outcome of subsequent laparoscopic gastrectomy for pT1 gastric cancer

BACKGROUND

The feasibility and oncological safety of non-curative endoscopic submucosal dissection (ESD) prior to additional gastrectomy for early gastric cancer (EGC) are still unclear. The aim of this study was to evaluate the impact of non-curative ESD on short- and long-term outcomes of subsequent laparoscopic gastrectomy (LG) for pathological T1 (pT1) EGC.

METHODS

We retrospectively investigated 422 patients who underwent LG for pT1 EGC between January 2007 and December 2017 at our center. Eighty-five of these patients underwent ESD with curative intent before surgery. Using propensity-score matching for sex, age, body mass index, American society of anesthesiologists score, history of previous abdominal surgery, tumor location, mucosal/submucosal infiltration, histology, lymph node metastasis, extent of lymph node dissection, operative method, lymphatic invasion, and venous invasion, the clinicopathologic and survival data of these patients were compared.

RESULTS

The median follow-up period was 60 (range 2-168) months. Using propensity-score matching from a total of 422 patients, 75 patients were selected in the Non-ESD and the ESD cohorts each. There were no significant differences in terms of characteristics and clinicopathological findings between the two groups. Furthermore, there were no significant differences in postoperative morbidity (13.3% vs. 17.3%; P = 0.497) and mortality (1.3% vs. 0%; P = 0.316). Both the 5-year overall survival ratio (88.8% vs. 86.9%; P = 0.757) and 5-year disease-specific survival ratio (97.1% vs. 98.4%; P = 0.333) were similar in the two groups.

CONCLUSION

Short- and long-term outcomes of LG in patients with pT1 EGC are not related to preoperative ESD history. Even for non-curative resections, ESD prior to surgery is feasible in terms of oncological and surgical outcomes in pT1 EGC.

Endoscopic diagnosis and treatment of gastric dysplasia and early cancer: Current evidence and what the future may hold

Gastric cancer accounts for a significant proportion of worldwide cancer-related morbidity and mortality. The well documented precancerous cascade provides an opportunity for clinicians to detect and treat gastric cancers at an endoscopically curable stage. In high prevalence regions such as Japan and Korea, this has led to the implementation of population screening programs. However, guidelines remain ambiguous in lower prevalence regions. In recent years, there have been many advances in the endoscopic diagnosis and treatment of early gastric cancer and precancerous lesions. More advanced endoscopic imaging has led to improved detection and characterization of gastric lesions as well as superior accuracy for delineation of margins prior to resection. In addition, promising early data on artificial intelligence in gastroscopy suggests a future role for this technology in maximizing the yield of advanced endoscopic imaging. Data on endoscopic resection (ER) are particularly robust in Japan and Korea, with high rates of curative ER and markedly reduced procedural morbidity. However, there is a shortage of data in other regions to support the applicability of protocols from these high prevalence countries. Future advances in endoscopic therapeutics will likely lead to further expansion of the current indications for ER, as both technology and proceduralist expertise continue to grow.

Dynamic diagnosis of early gastric cancer with microvascular blood flow rate using magnifying endoscopy (with video): A pilot study

BACKGROUND AND AIM

Magnifying endoscopy (ME) diagnostic algorithm for early gastric cancer (EGC) relies on qualitative features such as microvascular (MV) architecture and microsurface structure; however, it is a "static" diagnostic algorithm that uses still images. ME can visualize red blood cell flow within subepithelial microvessels in real time. Here, we evaluated the utility of using the MV blood flow rate in combination with ME for the diagnosis of EGC as a retrospective study.

METHODS

Patients with differentiated-type EGC (n = 10) or patchy redness (n = 10) underwent ME with blue laser imaging. The mean MV blood flow rates of EGC, patchy redness, and background mucosa were calculated by the mean movement distance of one tagging red blood cell using split images of ME with blue laser imaging videos. We compared the mean MV blood flow rate between EGC, patchy redness, and background mucosa and also calculated the MV blood flow imaging ratio (inside lesion/background mucosa) between EGC and patchy redness.

RESULTS

Mean MV blood flow rate was significantly lower in EGC (1481 μm/s; range 1057-1762) than in patchy redness (3859 μm/s; 2435-5899) or background mucosa (4140.6 μm/s; 2820-6247) (P < 0.01). The MV blood flow imaging ratio was significantly lower in EGC (0.39; 0.27-0.62) than in patchy redness (0.90; 0.78-1.1) (P < 0.01).

CONCLUSIONS

Dynamic diagnosis with MV blood flow rate using ME may be useful for the differential diagnosis of EGC and patchy redness. Endoscopic assessment of dynamic processes within the gastric mucosa may facilitate the diagnosis of EGC.

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.

Controversies in EUS: Do we need miniprobes?

This is the fifth in a series of papers entitled "Controversies in EUS." In the current paper, we deal with high-resolution catheter probes, otherwise known as EUS miniprobes (EUS-MPs). The application of miniprobes for early carcinomas in the entire intestinal tract, for subepithelial lesions, and for findings in the bile duct and pancreatic duct as well as endobronchial use is critically discussed. Submucous lesions, especially in the colon, but also early carcinomas in special cases are considered the most important indications. The argument is illustrated by numerous examples.

Comparison of the diagnostic efficacy of blue laser imaging with narrow band imaging for gastric cancer and precancerous lesions: a meta-analysis

BACKGROUND AND AIMS

novel endoscopic techniques including narrowband imaging (NBI) and blue laser imaging (BLI) have led to the improved detection of early stage gastric cancer and precancerous lesions. However, these techniques are not generally thought to be equivalent at present and BLI is generally considered as superior to NBI. Therefore, this comprehensive meta-analysis aimed to definitively compare the diagnostic efficacy of NBI and BLI for the diagnosis of gastric cancer and precancerous lesions.

METHODS

relevant articles were identified via searches of the PubMed, Web of Science, Embase and Cochrane Library databases from their inception until October 2019. In total, 28 relevant studies were identified and incorporated into the meta-analysis. RevMan5.3 was used to assess the relative diagnostic efficacy of these two imaging modalities in these studies. The threshold was assessed using Meta-DiSc 1.4 and STATA 14.0 for bivariate regression modeling of pooled studies.

RESULTS

the pooled sensitivity of BLI for gastric cancer was 0.89 (0.80, 0.95) and the specificity was 0.92 (0.76, 0.98). The pooled sensitivity of NBI for gastric cancer was 0.83 (0.75, 0.89) and the specificity was 0.95 (0.91, 0.97). The pooled sensitivity of BLI for precancerous lesions was 0.81 (0.71, 0.87) and the specificity was 0.90 (0.80, 0.96). The pooled sensitivity of NBI for precancerous lesions was 0.80 (0.75, 0.85) and the specificity was 0.88 (0.77, 0.94).

CONCLUSIONS

this study showed that both BLI and NBI have a very high diagnostic efficacy for the detection of gastric cancer and precancerous lesions, the sensitivity and specificity of these two approaches were similar.

[Clinical Practice Guideline for Endoscopic Resection of Early Gastrointestinal Cancer]

Although surgery was the standard treatment for early gastrointestinal cancers, endoscopic resection is now a standard treatment for early gastrointestinal cancers without regional lymph node metastasis. High-definition white light endoscopy, chromoendoscopy, and image-enhanced endoscopy such as narrow band imaging are performed to assess the edge and depth of early gastrointestinal cancers for delineation of resection boundaries and prediction of the possibility of lymph node metastasis before the decision of endoscopic resection. Endoscopic mucosal resection and/or endoscopic submucosal dissection can be performed to remove early gastrointestinal cancers completely by en bloc fashion. Histopathological evaluation should be carefully made to investigate the presence of risk factors for lymph node metastasis such as depth of cancer invasion and lymphovascular invasion. Additional treatment such as radical surgery with regional lymphadenectomy should be considered if the endoscopically resected specimen shows risk factors for lymph node metastasis. This is the first Korean clinical practice guideline for endoscopic resection of early gastrointestinal cancer. This guideline was developed by using mainly de novo methods and encompasses endoscopic management of superficial esophageal squamous cell carcinoma, early gastric cancer, and early colorectal cancer. This guideline will be revised as new data on early gastrointestinal cancer are collected.

Three-dimensional visualization improves the endoscopic diagnosis of superficial gastric neoplasia

BACKGROUND

Three-dimensional (3D) technology has been used in many fields, including flexible endoscopy. We evaluated the usefulness of 3D visualization for endoscopically diagnosing superficial gastric neoplasia.

METHODS

Twelve participants (4 novices, 4 trainees and 4 experts) evaluated two-dimensional (2D) and 3D endoscopic still images of 28 gastric neoplasias, obtained before ESD with white-light imaging (WLI) and narrow-band imaging (NBI). Assessments of the delineation accuracy of tumor extent and tumor morphology under 2D and 3D visualization were based on the histopathological diagnosis of ESD specimens. Participants answered visual analog scale (VAS) questionnaires (0-10, worst to best) concerning the (a) ease of recognition of lesion morphology, (b) lesion extent and (c) comprehensive endoscopic cognition under 2D and 3D visualization. The endpoints were the accuracy of tumor extent and morphology type and the degree of confidence in assessing (a)-(c).

RESULTS

The delineation accuracy of lesion extent [mean (95% confidence interval)] with WLI under 3D visualization [60.2% (56.1-64.3%)] was significantly higher than that under 2D visualization [52.3% (48.2-56.4%)] (P < 0.001). The accuracy with NBI under 3D visualization [70.3% (66.8-73.7%)] was also significantly higher than that under 2D visualization [64.2% (60.7-67.4%)] (P < 0.001). The accuracy of the morphology type with NBI under 3D visualization was significantly higher than that under 2D visualization (P = 0.004). The VAS for all aspects of endoscopic recognition under 3D visualization was significantly better than that under 2D visualization (P < 0.01).

CONCLUSIONS

Three-dimensional visualization can enhance the diagnostic quality for superficial gastric tumors.

Clinical practice guideline for endoscopic resection of early gastrointestinal cancer

Although surgery was the standard treatment for early gastrointestinal cancers, endoscopic resection is now a standard treatment for early gastrointestinal cancers without regional lymph node metastasis. High-definition white light endoscopy, chromoendoscopy, and image-enhanced endoscopy such as narrow band imaging are performed to assess the edge and depth of early gastrointestinal cancers for delineation of resection boundaries and prediction of the possibility of lymph node metastasis before the decision of endoscopic resection. Endoscopic mucosal resection and/or endoscopic submucosal dissection can be performed to remove early gastrointestinal cancers completely by en bloc fashion. Histopathological evaluation should be carefully made to investigate the presence of risk factors for lymph node metastasis such as depth of cancer invasion and lymphovascular invasion. Additional treatment such as radical surgery with regional lymphadenectomy should be considered if the endoscopically resected specimen shows risk factors for lymph node metastasis. This is the first Korean clinical practice guideline for endoscopic resection of early gastrointestinal cancer. This guideline was developed by using mainly de novo methods and encompasses endoscopic management of superficial esophageal squamous cell carcinoma, early gastric cancer, and early colorectal cancer. This guideline will be revised as new data on early gastrointestinal cancer are collected.

Application of artificial intelligence using a convolutional neural network for diagnosis of early gastric cancer based on magnifying endoscopy with narrow-band imaging

BACKGROUND AND AIM

Magnifying endoscopy with narrow-band imaging (ME-NBI) has made a huge contribution to clinical practice. However, acquiring skill at ME-NBI diagnosis of early gastric cancer (EGC) requires considerable expertise and experience. Recently, artificial intelligence (AI), using deep learning and a convolutional neural network (CNN), has made remarkable progress in various medical fields. Here, we constructed an AI-assisted CNN computer-aided diagnosis (CAD) system, based on ME-NBI images, to diagnose EGC and evaluated the diagnostic accuracy of the AI-assisted CNN-CAD system.

METHODS

The AI-assisted CNN-CAD system (ResNet50) was trained and validated on a dataset of 5574 ME-NBI images (3797 EGCs, 1777 non-cancerous mucosa and lesions). To evaluate the diagnostic accuracy, a separate test dataset of 2300 ME-NBI images (1430 EGCs, 870 non-cancerous mucosa and lesions) was assessed using the AI-assisted CNN-CAD system.

RESULTS

The AI-assisted CNN-CAD system required 60 s to analyze 2300 test images. The overall accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of the CNN were 98.7%, 98%, 100%, 100%, and 96.8%, respectively. All misdiagnosed images of EGCs were of low-quality or of superficially depressed and intestinal-type intramucosal cancers that were difficult to distinguish from gastritis, even by experienced endoscopists.

CONCLUSIONS

The AI-assisted CNN-CAD system for ME-NBI diagnosis of EGC could process many stored ME-NBI images in a short period of time and had a high diagnostic ability. This system may have great potential for future application to real clinical settings, which could facilitate ME-NBI diagnosis of EGC in practice.

Magnifying endoscopy in detecting early gastric cancer: A network meta-analysis of prospective studies

BACKGROUND

Conventional white-light imaging endoscopy (C-WLI) had a significant number of misdiagnosis in early gastric cancer (EGC), and magnifying endoscopy (ME) combined with different optical imaging was more accurate in the diagnosis of EGC. This study aimed to evaluate the accuracy of ME and compare the accuracy of ME with different optical imaging in detecting EGC.

METHODS

A comprehensive literature search was conducted to identify all relevant studies. Pair-wise meta-analysis was conducted to evaluate the accuracy of ME, and Bayesian network meta-analysis was performed to combine direct and indirect evidence and estimate the relative effects.

RESULTS

Eight prospective studies were identified with a total of 5948 patients and 3 optical imaging in ME (ME with WLI (M-WLI), ME with narrow-band imaging (M-NBI), and ME with blue laser imaging (M-BLI)). Pair-wise meta-analysis showed a higher accuracy of ME than C-WLI (OR: 2.97, 95% CI: 1.68∼5.25). In network meta-analysis, both M-NBI and M-BLI were more accurate than M-WLI (OR: 2.56, 95% CI: 2.13∼3.13; OR: 3.13, 95% CI: 1.85∼5.71). There was no significant difference between M-NBI and M-BLI.

CONCLUSION

ME was effective in improving the detecting rate of EGC, especially with NBI or BLI.

A case of signet ring cell carcinoma and mucosa-associated lymphoid tissue lymphoma of the stomach diagnosed simultaneously via magnifying endoscopy with narrow-band imaging

We present the case of a 57-year-old woman who experienced 3 weeks of intermittent tarry stools and epigastric pain. She had a 25-year history of smoking and a 12-year history of heavy alcohol consumption but had discontinued both 12 years prior. Laboratory investigations revealed elevated anti-H. Pylori IgG antibody levels. Conventional upper gastrointestinal endoscopy revealed two lesions. Magnifying endoscopy with narrow-band imaging showed the characteristic appearance of a diffuse-type gastric cancer 0-IIc lesion with a demarcation line and abnormal vessels ("wavy micro-vessels" and a "cork-screw pattern"). There was also "ballooning" of the crypts and a "tree-like vessel appearance" in an "unstructured area" characteristic of gastric mucosa-associated lymphoid tissue lymphoma with ulceration. Accurate target biopsies were obtained. We performed a laparoscopic total gastrectomy with D1 lymphadenectomy. Pathological examination revealed poorly differentiated stage I adenocarcinoma of the stomach with features of signet ring cell carcinoma as well as stage I mucosa-associated lymphoid tissue lymphoma. In conclusion, we encountered a case of co-existing diffuse-type gastric cancer and gastric mucosa-associated lymphoid tissue lymphoma. Magnifying endoscopy with narrow-band imaging was effective for diagnosing these two co-existing tumors and resulted in the collection of adequate biopsy specimens allowing for an accurate pathological diagnosis and optimal treatment.

Near-focus magnification and second-generation narrow-band imaging for early gastric cancer in a randomized trial

BACKGROUND

Magnifying endoscopy with narrow-band imaging (NBI) is effective for the diagnosis of early gastric cancer (EGC). However, magnifying endoscopy is not yet popular globally because of the required level of skill and lack of availability. To overcome these problems, dual-focus endoscopy (standard- and near-focus (NF) modes) has been developed. In this study, we evaluated the diagnostic performance of NF with second-generation (2G)-NBI (NF-NBI) for the diagnosis of EGC.

METHODS

This was a secondary analysis of a multicenter randomized controlled trial of 4523 high-risk patients who underwent gastroscopies at 13 institutions in Japan. Patients were randomly assigned to white-light imaging (WLI) followed by 2G-NBI or to 2G-NBI followed by WLI. Lesions suspicious for EGC, newly detected by non-magnifying WLI or 2G-NBI, were subsequently observed with NF-NBI. All detected lesions were biopsied or resected. The diagnostic performance of NF-NBI was compared with the final histology.

RESULTS

A total of 870 detected lesions (145 EGC, 725 non-EGC) were analyzed. Overall diagnostic performance for EGC using NF-NBI was accuracy 87.7%, sensitivity 60.7%, specificity 93.1%, positive predictive value 63.8%, and negative predictive value 92.2%. There were no significant differences in diagnostic performance between lesions detected by WLI or 2G-NBI. For lesions diagnosed with high (333 lesions) and low (537 lesions) confidences, accuracy was 92.2% and 84.9%, sensitivity was 64.7% and 58.5%, and specificity was 90.5% and 88.8%, respectively.

CONCLUSION

The diagnostic performance of NF-NBI is good and acceptable for diagnosis of EGC in combination with either WLI or 2G-NBI.

Image-enhanced endoscopy for gastric preneoplastic conditions and neoplastic lesions: a systematic review and meta-analysis

BACKGROUND : Image-enhanced endoscopy (IEE) improves the accuracy of endoscopic diagnosis. We aimed to assess the value of IEE for gastric preneoplastic conditions and neoplastic lesions. METHODS : Medline and Embase were searched until December 2018. Studies allowing calculation of diagnostic measures were included. Risk of bias and applicability were assessed using QUADAS-2. Subgroup analysis was performed to explore heterogeneity. RESULTS : 44 studies met the inclusion criteria. For gastric intestinal metaplasia (GIM), narrow-band imaging (NBI) obtained a pooled sensitivity and specificity of 0.79 (95 %CI 0.72-0.85) and 0.91 (95 %CI 0.88-0.94) on per-patient basis; on per-biopsy basis, it was 0.84 (95 %CI 0.81-0.86) and 0.95 (95 %CI 0.94-0.96), respectively. Tubulovillous pattern was the most accurate marker to detect GIM and it was effectively assessed without high magnification. For dysplasia, NBI showed a pooled sensitivity and specificity of 0.87 (95 %CI 0.84-0.89) and 0.97 (95 %CI 0.97-0.98) on per-biopsy basis. The use of magnification improved the performance of NBI to characterize early gastric cancer (EGC), especially when the vessel plus surface (VS) classification was applied. Regarding other technologies, trimodal imaging also obtained a high accuracy for dysplasia (sensitivity 0.93 [95 %CI 0.85-0.98], specificity 0.98 [95 %CI 0.92-1.00]). For atrophic gastritis, no specific pattern was noted and none of the technologies reached good diagnostic yield. CONCLUSION : NBI is highly accurate for GIM and dysplasia. The presence of tubulovillous pattern and the VS classification seem to be useful to detect GIM and characterize EGC, respectively. These features should be used in current practice and to standardize endoscopic criteria for other technologies.

Three-dimensional flexible endoscopy enables more accurate endoscopic recognition and endoscopic submucosal dissection marking for superficial gastric neoplasia: a pilot study to compare two- and three-dimensional imaging

BACKGROUND

Three-dimensional (3D) visualization offers better depth recognition than two-dimensional (2D) imaging, thus helping to provide more useful information. We compared 3D and 2D endoscopy with regard to endoscopic recognition and endoscopic submucosal dissection (ESD) marking for superficial gastric neoplasia.

METHODS

ESD marking was performed on half of a neoplasia margin under 2D observation and the on other half under 3D observation for 28 gastric lesions (26 early gastric cancers and 2 adenomas). The accuracy of ESD marking was evaluated based on the distance between the pathological and endoscopic neoplasia margins measured on histology sections of ESD specimens. The technical ease of ESD marking and endoscopic lesion recognition (lesion morphology, lesion extent, and comprehensive endoscopic cognition) were assessed using visual analog scale (VAS) questionnaires.

RESULTS

The mean distance between the pathological and endoscopic margins under 3D observation (1.03 ± 0.80 mm) was significantly (p = 0.002) shorter than that under 2D observation (1.94 ± 1.96 mm). The VAS for technical ease of ESD marking under 3D observation was significantly better (p < 0.01) than that under 2D observation. The VAS for all aspects of endoscopic recognition under 3D observation was significantly better (p < 0.01) than under 2D observation.

CONCLUSIONS

3D flexible endoscopy achieved more accurate endoscopic recognition and ESD marking for superficial gastric neoplasia than a 2D approach in a clinical setting of ESD.

Impact of endoscopic resection on the choice of surgical procedure in patients with additional laparoscopic gastrectomy

BACKGROUND

Additional surgery is recommended for patients with noncurative resection after endoscopic submucosal dissection (ESD) for early gastric cancer. Additional resection requires the excision of an area larger than that of the resected mucosa in ESD, which is larger than the lesion, with convergence of the gastric mucosa due to scarring. Thus, the selection of the surgical procedure for lesion removal in specific areas can be affected by ESD. This study therefore aimed to evaluate the impact of ESD on the selection of additional gastrectomy in patients with early gastric cancer in the boundary area between the upper third and middle third of the stomach (UM boundary region).

METHODS

Between January 2013 and June 2018, laparoscopic gastrectomy was performed in 89 patients with cT1N0M0 gastric cancer located only in the UM boundary region. The patients' backgrounds and surgical and pathological results were retrospectively investigated. The predictive factors for performing laparoscopic distal gastrectomy (LDG) were evaluated by multivariate analysis.

RESULTS

Among 89 patients, 23 patients underwent ESD before surgery. LDG was significantly less often performed in the ESD-surgery group than in the surgery-only group (34.8% vs. 72.7%; p = 0.003). Preoperative ESD was an independent negative predictor of LDG (odds ratio = 0.266; p = 0.025).

CONCLUSIONS

Preoperative ESD has an impact on the selection of the type of additional gastrectomy, including reducing the conduct of LDG for early gastric cancer in the UM boundary region.

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.

Clinical Practice Guideline for Endoscopic Resection of Early Gastrointestinal Cancer

Although surgery was the standard treatment for early gastrointestinal cancers, endoscopic resection is now a standard treatment for early gastrointestinal cancers without regional lymph node metastasis. High-definition white light endoscopy, chromoendoscopy, and image-enhanced endoscopy such as narrow band imaging are performed to assess the edge and depth of early gastrointestinal cancers for delineation of resection boundaries and prediction of the possibility of lymph node metastasis before the decision of endoscopic resection. Endoscopic mucosal resection and/or endoscopic submucosal dissection can be performed to remove early gastrointestinal cancers completely by en bloc fashion. Histopathological evaluation should be carefully made to investigate the presence of risk factors for lymph node metastasis such as depth of cancer invasion and lymphovascular invasion. Additional treatment such as radical surgery with regional lymphadenectomy should be considered if the endoscopically resected specimen shows risk factors for lymph node metastasis. This is the first Korean clinical practice guideline for endoscopic resection of early gastrointestinal cancer. This guideline was developed by using mainly de novo methods and encompasses endoscopic management of superficial esophageal squamous cell carcinoma, early gastric cancer, and early colorectal cancer. This guideline will be revised as new data on early gastrointestinal cancer are collected.

Clinical Practice Guideline for Endoscopic Resection of Early Gastrointestinal Cancer

Although surgery was the standard treatment for early gastrointestinal cancers, endoscopic resection is now a standard treatment for early gastrointestinal cancers without regional lymph node metastasis. High-definition white light endoscopy, chromoendoscopy, and image-enhanced endoscopy such as narrow band imaging are performed to assess the edge and depth of early gastrointestinal cancers for delineation of resection boundaries and prediction of the possibility of lymph node metastasis before the decision of endoscopic resection. Endoscopic mucosal resection and/or endoscopic submucosal dissection can be performed to remove early gastrointestinal cancers completely by <i>en bloc</i> fashion. Histopathological evaluation should be carefully made to investigate the presence of risk factors for lymph node metastasis such as depth of cancer invasion and lymphovascular invasion. Additional treatment such as radical surgery with regional lymphadenectomy should be considered if the endoscopically resected specimen shows risk factors for lymph node metastasis. This is the first Korean clinical practice guideline for endoscopic resection of early gastrointestinal cancer. This guideline was developed by using mainly de novo methods and encompasses endoscopic management of superficial esophageal squamous cell carcinoma, early gastric cancer, and early colorectal cancer. This guideline will be revised as new data on early gastrointestinal cancer are collected.

Convolutional neural network for the diagnosis of early gastric cancer based on magnifying narrow band imaging

BACKGROUND

Magnifying endoscopy with narrow band imaging (M-NBI) has been applied to examine early gastric cancer by observing microvascular architecture and microsurface structure of gastric mucosal lesions. However, the diagnostic efficacy of non-experts in differentiating early gastric cancer from non-cancerous lesions by M-NBI remained far from satisfactory. In this study, we developed a new system based on convolutional neural network (CNN) to analyze gastric mucosal lesions observed by M-NBI.

METHODS

A total of 386 images of non-cancerous lesions and 1702 images of early gastric cancer were collected to train and establish a CNN model (Inception-v3). Then a total of 341 endoscopic images (171 non-cancerous lesions and 170 early gastric cancer) were selected to evaluate the diagnostic capabilities of CNN and endoscopists. Primary outcome measures included diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value.

RESULTS

The sensitivity, specificity, and accuracy of CNN system in the diagnosis of early gastric cancer were 91.18%, 90.64%, and 90.91%, respectively. No significant difference was spotted in the specificity and accuracy of diagnosis between CNN and experts. However, the diagnostic sensitivity of CNN was significantly higher than that of the experts. Furthermore, the diagnostic sensitivity, specificity and accuracy of CNN were significantly higher than those of the non-experts.

CONCLUSIONS

Our CNN system showed high accuracy, sensitivity and specificity in the diagnosis of early gastric cancer. It is anticipated that more progress will be made in optimization of the CNN diagnostic system and further development of artificial intelligence in the medical field.

Reliability and accuracy of blue light imaging for staging of intestinal metaplasia in the stomach

Background and aims: An endoscopic grading system (EGGIM) using narrow-band-imaging (NBI) has shown to accurately identify patients with extensive gastric intestinal metaplasia (GIM). However, description with alternative systems such as blue-light-imaging (BLI) is limited. The aim of this study is to determine the reliability and accuracy of BLI-bright regarding diagnosis and staging of GIM.Methods: Reliability of WLE (white-light-endoscopy) and BLI among 6 observers was assessed using a standard classification based on endoscopic images. Afterward, 37 patients were submitted to gastroscopy using FujifilmEG-760Z and endoscopists had to determine EGGIM score using BLI-bright and to perform gastric biopsies for operative-link-of-gastric-intestinal-metaplasia (OLGIM) calculation. BLI-bright accuracy was determined by comparing results with prior EGGIM scores with NBI and current OLGIM.Results: Compared with WLE, the interobserver reliability between observers was substantially better with BLI (Weighted Kappa: 0.8 vs 0.41). There was an 84% agreement between BLI and NBI assessing EGGIM intervals (EGGIM 0-4vs5-10). The area under the ROC curve was 0.90 (95%CI: 0.79-1.0) using the cut-off of EGGIM > 4 to determine advanced GIM, with a sensitivity of 100% (95%CI: 88-100%).Discussion: BLI-bright is reliable for the diagnosis of gastric intestinal metaplasia and agrees significantly with NBI evaluation. Preliminary data suggests high sensitivity for identifying patients with increased risk of gastric cancer.

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.

Evaluation of New Technologies in Gastrointestinal Endoscopy

Gastrointestinal (GI) tumors are the most commonly diagnosed cancers worldwide and the second leading cause of cancer-related death. Endoscopy is the gold standard for diagnosis of GI cancers. Early diagnosis of GI tumors by endoscopy at the precancerous or early stage may decrease the prevalence and mortality rate of GI cancers. The preventive role of endoscopic interventions and the limitations of conventional white-light endoscopy have given rise to myriad innovations. Chromoendoscopy with dye injection can be used to detect lesions at an early stage. However, the prolonged procedure duration and steep learning curve are disadvantages of chromoendoscopy. Recent technological advances in imaging enhancement have enabled detection of GI lesions without the need for dye injection, using digital chromoendoscopy systems, of which flexible spectral-imaging color enhancement, narrow-band imaging, and I-Scan are the most frequently used. The combination of endoscopic image magnification and high-definition optical systems using digital endoscopic methods has increased the diagnostic value of endoscopy. The development of confocal laser endomicroscopy has also improved in vivo endoscopic diagnosis. This review focuses on the latest technological innovations in endoscopy.

Magnifying Blue Laser Imaging versus Magnifying Narrow-Band Imaging for the Diagnosis of Early Gastric Cancer: A Prospective, Multicenter, Comparative Study

BACKGROUND/AIMS

The diagnostic efficacy of magnifying blue laser imaging (M-BLI) and M-BLI in bright mode (M-BLI-bright) in the identification of early gastric cancer (EGC) was evaluated for comparison to that of magnifying narrow-band imaging (M-NBI).

METHODS

This prospective, multicenter study evaluated 114 gastric lesions examined using M-BLI, M-BLI-bright, and M-NBI between May 2012 and November 2012; 104 EGCs were evaluated by each modality. The vessel plus surface classification system was used to evaluate the demarcation line (DL), microvascular pattern (MVP), and microsurface pattern (MSP).

RESULTS

M-BLI, M-BLI-bright, and M-NBI revealed a DL for 96.1, 98.1, and 98.1% and irregular MVP for 95.1, 95.1, and 96.2% of lesions, respectively, with no significant difference. Irregular MSP was observed by M-BLI, M-BLI-bright, and M-NBI in 97.1, 90.4, and 78.8% of lesions, respectively, with significant differences (p < 0.001). The proportion of moderately differentiated adenocarcinoma with irregular MSP on M-BLI and absent MSP on M-NBI was significantly higher than that with irregular MSP on M-BLI and M-NBI (35.0 and 9.9%, respectively; p = 0.002).

CONCLUSION

M-BLI and M-BLI-bright provided excellent visualization of microstructures and microvessels similar to M-NBI. Irregular MSP in a moderately differentiated adenocarcinoma might be frequently visualized using M-BLI and M-BLI-bright compared with using M-NBI.

The accuracy of magnifying narrow band imaging (ME-NBI) in distinguishing between cancerous and noncancerous gastric lesions: A meta-analysis

BACKGROUND

Previous clinical trials have demonstrated the diagnostic accuracy of magnifying narrow-band (ME-NBI) for gastric cancerous lesions, but the results are inconsistent. The purpose of this meta-analysis is to investigate the accuracy of ME-NBI in distinguishing between cancerous and noncancerous gastric lesions.

METHODS

Systematic literature searches were conducted until October 2016 in PubMed, Embase by 2 independent reviewers. Meta-analysis was performed to calculate the pooled sensitivity, specificity. Two authors independently evaluated studies for inclusion, rated methodological quality, and abstracted relevant data. Meta-analytic method was used to construct summary receiver operating characteristic curves, and pooled sensitivity, specificity were calculated.

RESULTS

Nine studies enrolling 5398 lesions were included. The pooled sensitivity, specificity were 88% (95% confidence interval [CI]: 78-93%), 96% (95% CI: 91-98%), respectively. The area under the curve (AUC) was 0.97. There was a large heterogeneity between the included studies. Studies with lesions ≤ 10 mm still had a high pooled sensitivity of 81% (95% CI: 73-90%) and specificity of 97% (95% CI: 95-100%). Studies which analyzed resected specimens had a sensitivity of 91% (95 CI: 82-99%) and specificity of 88% (95% CI: 83-94%), and studies which analyzed biopsied specimens had a sensitivity of 85% (95 CI: 74-96%) and specificity of 99% (95% CI: 98-99%).

CONCLUSIONS

ME-NBI is highly accurate and consistent to distinguish between gastric cancerous and noncancerous lesions.

Gastric Cancer as Preventable Disease

Gastric cancer, 1 of the 5 most common causes of cancer death, is associated with a 5-year overall survival rate less than 30%. A minority of cancers occurs as part of syndromic diseases; more than 90% of adenocarcinomas are considered as the ultimate consequence of a longstanding mucosal inflammation. Helicobacter pylori infection is the leading etiology of non-self-limiting gastritis, which may result in atrophy of the gastric mucosa and impaired acid secretion. Gastric atrophy establishes a field of cancerization prone to further molecular and phenotypic changes, possibly resulting in cancer growth. This well-understood natural history provides the clinicopathologic rationale for primary and secondary cancer prevention strategies. A large body of evidence demonstrates that combined primary (H pylori eradication) and secondary (mainly endoscopy) prevention efforts may prevent or limit the progression of gastric oncogenesis. This approach, which is tailored to different country-specific gastric cancer incidence, socioeconomic, and cultural factors, requires that the complementary competences of gastroenterologists, oncologists, and pathologists be amalgamated into a common strategy of health policy.