Improving the Endoscopic Detection Rate in Patients with Early Gastric Cancer

Clinical and endoscopic features of metachronous gastric cancer with possible lymph node metastasis after endoscopic submucosal dissection and Helicobacter pylori eradication

BACKGROUND

Several studies have reported the metachronous gastric cancers (MGCs) with possible lymph node metastasis (LNM) after endoscopic submucosal dissection (ESD) and Helicobacter pylori (H. pylori) eradication in which a curative ESD had not been achieved. There have been no published reports of evaluations of the features of patients with MGC with possible LNM after ESD and H. pylori eradication.

METHODS

We identified 264 patients with 369 MGCs after H. pylori eradication among the 4354 patients with 5059 early gastric cancers (EGCs) who underwent ESD between 1999 and 2017 and divided them into two groups: patients with MGCs with possible LNM (Group I) and patients with MGCs undergone curative ESD (Group II). We retrospectively compared the features of patients with MGCs and patients with EGCs at index ESD in the two groups.

RESULT

Group I consisted of 20 patients with 21 MGCs, and Group II consisted of 244 patients with 348 MGCs. Group I lesions were significantly more common in the posterior wall than in the lesser curvature (odds ratio [OR] = 3.97; 95% confidence intervals [CI] 1.20-13.10). Development of Group I was significantly more common in patients with a body mass index (BMI) < 19.0 kg/m2 than in patients with a BMI ≥ 19.0 kg/m2 at index ESD (OR = 4.44; 95% CI 1.30-15.20).

CONCLUSIONS

During surveillance endoscopy after gastric ESD and H. pylori eradication, the posterior wall should be carefully examined to detect MGCs early. Lower BMI may be associated with the development of MGCs with possible LNM.

Preoperative diagnosis of tumor depth in gastric cancer using transabdominal ultrasonography compared to using endoscopy and computed tomography

BACKGROUND

An accurate evaluation method for preoperative diagnosis has not yet been established in patients with gastric cancer (GC), though it is essential for optimal treatment. Current standard modalities are endoscopy and contrast computed tomography (CT). In this study, we investigated the efficacy and limitations of transabdominal ultrasonography (TUS) for the assessment of tumor invasion.

METHODS

We enrolled 178 consecutive patients with GC evaluated by TUS, endoscopy, and contrast CT before gastrectomy. For the TUS examination, patients ingested water to fill their stomachs. The clinical staging determined using these modalities was compared to the pathological staging.

RESULTS

The overall accuracy of clinical T staging using TUS was 47.8% (pT1a: 5.8% (2/35); pT1b: 58.8% (20/35); pT2: 69.6% (16/23); pT3: 66.7% (22/33); pT4a: 46% (23/50); pT4b: 100% (2/2)). Using endoscopy, contrast CT, and TUS, the overall accuracy was 60.7%. The accuracy of TUS was associated with the tumor region (U region: 50% (14/28); M: 31.8% (14/44); L: 53.7% (57/106); P = 0.048), but not with the cross-sectional parts (P = 0.49). Multivariate analysis identified inaccurate TUS as independently correlating with tumor region (M vs. U/L, odds ratio (OR) = 3.11, 95% confidence interval (CI) 1.41-6.87; P = 0.005) and pT (pT1 vs. pT2-4, OR = 3.00, 95%CI 1.31-6.87; P = 0.009).

CONCLUSIONS

The present study demonstrated the importance of TUS in evaluating GC. Thus, TUS may be useful for clinical T staging in certain circumstances, leading to treatment optimization.

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.

Risk factors for early gastric cancer: focus on Helicobacter pylori gastritis

Background: Gastric cancer is a global health problem, and the incidence and geographical distribution of different types of gastric cancer varies. Particularly, noncardiac gastric cancer is more prevalent in East Asia, Central and Eastern Europe, Latin America, and Africa. Infection with Helicobacter pylori, which was discovered in 1982, is a common cause of chronic gastritis, and the association between H. pylori infection and gastric adenocarcinoma is well established.Current Concepts: Gastric cancer is histologically divided into 2 types: intestinal and diffuse. H. pylori infection is considered as the main risk factor for the development of both types of gastric tumors. The most documented course of development of stomach cancer is following cellular metaplasia due to chronic inflammation, damage, and repair. Various molecular alterations caused by H. pylori are identified not only in gastric cancer but also in precancerous lesions. Recently, many studies have attempted to diagnose H. pylori gastritis and precancerous lesions using endoscopy.Discussion and Conclusion: Recent studies have shown that eradication therapy stabilizes or reduces the risk of developing gastric cancer. Therefore, the diagnosis and understanding of gastritis and precancerous lesions caused by H. pylori are the first step in the prevention of gastric cancer.

A comparative time-dependent study of hematology, serum gastrin concentrations, and gastroscopic assessment of meloxicam-induced gastric ulceration in dogs

Background

Diagnosis of gastric ulcers by methods other than gastroscopy in dogs has been problematic for many years and biomarkers such as serum gastrin (SG) concentrations have been introduced as a noninvasive way to evaluate gastric diseases.

Objectives

To determine the time course changes in hematology, SG concentrations, and gastroscopic images of meloxicam‐induced gastric ulceration in dogs and identify a relationship between SG and gastroscopic image analysis in a clinical setting.

Animals

Fifteen crossbreed dogs.

Methods

Two groups: control (n = 5) and meloxicam‐treated (n = 10). The meloxicam‐treated group received meloxicam 0.2 mg/kg PO for 15 days. Clinical signs, hematology, SG, and image analysis (PI, pixel intensity; ID, integrated density; RA, relative area; and UI, ulcer index) of the gastroscopic examination were evaluated across time (T5, time 5 day; T10, time 10 day; and T15, time 15 day).

Results

Significant changes were observed among 3 time points and between the 2 groups in terms of SG, hematology, and gastroscopic image analysis. In the meloxicam‐treated group, decreases in hemoglobin concentration, red blood cell count and packed cell volume at T10 and T15 (P = .0001) were observed, whereas SG, ID, and UI increased over time (P < .0001). The PI decreased significantly (P = .0001) in the meloxicam‐treated group compared to controls. Significant correlations were found between SG and PI, and ID and ulcer area (r = −0.89, 0.81, 0.64), respectively.

Conclusion and Clinical Importance

Gastroscopy is the gold standard for early descriptive diagnosis of gastric ulcerations in dogs, and SG is a good indicator for meloxicam‐induced gastric ulcers in dogs and can predict the gastroscopic score of the lesion.

Identification of gaze pattern and blind spots by upper gastrointestinal endoscopy using an eye-tracking technique

BACKGROUND

The lesion detection rate of esophagogastroduodenoscopy (EGD) varies depending on the degree of experience of the endoscopist and anatomical blind spots. This study aimed to identify gaze patterns and blind spots by analyzing the endoscopist's gaze during real-time EGD.

METHODS

Five endoscopists were enrolled in this study. The endoscopist's eye gaze tracked by an eye tracker was selected from the esophagogastric junction to the second portion of the duodenum without the esophagus during insertion and withdrawal, and then matched with photos. Gaze patterns were visualized as a gaze plot, blind spot detection as a heatmap, observation time (OT), fixation duration (FD), and FD-to-OT ratio.

RESULTS

The mean OT and FD were 11.10 ± 11.14 min and 8.37 ± 9.95 min, respectively, and the FD-to-OT ratio was 72.5%. A total of 34.3% of the time was spent observing the antrum. When observing the body of the stomach, it took longer to observe the high body in the retroflexion view and the low-to-mid body in the forward view.

CONCLUSIONS

It is necessary to minimize gaze distraction and observe the posterior wall in the retroflexion view. Our results suggest that eye-tracking techniques may be useful for future endoscopic training and education.

Intelligent detection endoscopic assistant: An artificial intelligence-based system for monitoring blind spots during esophagogastroduodenoscopy in real-time

BACKGROUND

Observation of the entire stomach during esophagogastroduodenoscopy (EGD) is important; however, there is a lack of effective evaluation tools.

AIMS

To develop an artificial intelligence (AI)-assisted EGD system able to automatically monitor blind spots in real-time.

METHODS

An AI-based system, called the Intelligent Detection Endoscopic Assistant (IDEA), was developed using a deep convolutional neural network (DCNN) and long short-term memory (LSTM). The performance of IDEA for recognition of gastric sites in images and videos was evaluated. Primary outcomes included diagnostic accuracy, sensitivity, and specificity.

RESULTS

A total of 170,297 images and 5779 endoscopic videos were collected to develop the system. As the test group, 3100 EGD images were acquired to evaluate the performance of DCNN in recognition of gastric sites in images. The sensitivity, specificity, and accuracy of DCNN were determined as 97.18%,99.91%, and 99.83%, respectively. To assess the performance of IDEA in recognition of gastric sites in EGD videos, 129 videos were used as the test group. The sensitivity, specificity, and accuracy of IDEA were 96.29%,93.32%, and 95.30%, respectively.

CONCLUSIONS

IDEA achieved high accuracy for recognition of gastric sites in real-time. The system can be applied as a powerful assistant tool for monitoring blind spots during EGD.

Taking More Gastroscopy Images Increases the Detection Rate of Clinically Significant Gastric Lesions: Validation of a Systematic Screening Protocol for the Stomach

Background/Aims: For systematic screening protocol for the stomach (SSS), 22 gastroscopy images are considered sufficient to avoid blind spots during gastroscopy. The aim of this study was to investigate the relationship between the number of gastroscopy images taken during the gastroscopy procedure and the detection rate of clinically significant gastric lesions (CSGLs).Materials and Methods: We retrospectively reviewed the data obtained from a cohort of consecutive subjects at a health promotion center. The primary outcome measure was the detection rate of CSGLs per endoscopist, according to the number of gastroscopy images. We also analyzed whether all the CSGLs were detected via SSS.Results: The mean number of gastroscopy images obtained by eight endoscopists was 27.6±10.5 in 2,912 subjects without CSGLs and without biopsies. Among the 5,970 subjects who underwent gastroscopy by the eight endoscopists, 712 CSGLs were detected in 551 subjects. Fifty-six CSGLs (7.9%) in 55 subjects (10.0%) were not detected during the SSS. Photo-endoscopists who took more images achieved a higher detection rate of CSGLs than those who took fewer images (adjusted OR 2.07, 95% CI 1.41~3.05; <i>P</i><0.0001).Conclusions: The modified SSS, which included 22 SSS images, the fundus, and the saddle area, detected significantly more CSGLs. This modified SSS should be validated with further prospective studies.

Comparing blind spots of unsedated ultrafine, sedated, and unsedated conventional gastroscopy with and without artificial intelligence: a prospective, single-blind, 3-parallel-group, randomized, single-center trial

BACKGROUND AND AIMS

EGD is the most vital procedure for the diagnosis of upper GI lesions. We aimed to compare the performance of unsedated ultrathin transoral endoscopy (U-TOE), unsedated conventional EGD (C-EGD), and sedated C-EGD with or without the use of an artificial intelligence (AI) system.

METHODS

In this prospective, single-blind, 3-parallel-group, randomized, single-center trial, 437 patients scheduled to undergo outpatient EGD were randomized to unsedated U-TOE, unsedated C-EGD, or sedated C-EGD, and each group was then divided into 2 subgroups: with or without the assistance of an AI system to monitor blind spots during EGD. The primary outcome was the blind spot rate of these 3 groups with the assistance of AI. The secondary outcomes were to compare blind spot rates of unsedated U-TOE, unsedated, and sedated C-EGD with or without the assistance of AI, respectively, and the concordance between AI and the endoscopists' review.

RESULTS

The blind spot rate with AI-assisted sedated C-EGD was significantly lower than that of unsedated U-TOE and unsedated C-EGD (3.42% vs 21.77% vs 31.23%, respectively; P < .05). The blind spot rate of the AI subgroup was lower than that of the control subgroup in all 3 groups (sedated C-EGD: 3.42% vs 22.46%, P < .001; unsedated U-TOE: 21.77% vs 29.92%, P < .001; unsedated C-EGD: 31.23% vs 42.46%, P < .001).

CONCLUSIONS

The blind spot rate of sedated C-EGD was the lowest among the 3 types of EGD, and the addition of AI had a maximal effect on sedated C-EGD. (Clinical trial registration number: ChiCTR1900020920.).

TriZ-a rotation-tolerant image feature and its application in endoscope-based disease diagnosis

Endoscopy is becoming one of the widely-used technologies to screen the gastric diseases, and it heavily relies on the experiences of the clinical endoscopists. The location, shape, and size are the typical patterns for the endoscopists to make the diagnosis decisions. The contrasting texture patterns also suggest the potential lesions. This study designed a novel rotation-tolerant image feature, TriZ, and demonstrated the effectiveness on both the rotation invariance and the lesion detection of three gastric lesion types, i.e., gastric polyp, gastric ulcer, and gastritis. TriZ achieved 87.0% in the four-class classification problem of the three gastric lesion types and the healthy controls, averaged over the twenty random runs of 10-fold cross-validations. Due to that biomedical imaging technologies may capture the lesion sites from different angles, the symmetric image feature extraction algorithm TriZ may facilitate the biomedical image based disease diagnosis modeling. Compared with the 378,434 features of the HOG algorithm, TriZ achieved a better accuracy using only 126 image features.

HIGH-RISK GASTRIC PATHOLOGY AND PREVALENT AUTOIMMUNE DISEASES IN PATIENTS WITH PERNICIOUS ANEMIA

OBJECTIVE

Pernicious anemia (PA) develops from atrophic gastritis due to autoimmune destruction of parietal cells and results in achlorhydria, vitamin B12 and iron deficiencies, anemia, neurologic deficits, and premalignant and malignant stomach lesions. We report the presentation, diagnosis and gastric complications of PA in patients from an endocrinology practice.

METHODS

Thirty-four patients (31 female, 3 male) with PA who underwent esophagogastroduodenoscopy (EGD) or gastrectomy were identified. Pertinent clinical, laboratory, and pathology findings were reviewed and summarized.

RESULTS

The mean age of patients was 58.6 ± 14.2 years; the onset of PA was age 50.2 ± 15.3 years. Anemia reflected vitamin B12 and/or iron deficiencies. Parietal cell antibodies (PCA) were detected in 97% of patients, and intrinsic factor blocking antibody (IFBA) was found in 52%. Fasting gastrin and chromogranin A levels were elevated (1,518.0 ± 1,588.3 pg/mL, and 504.9.1 ± 1,524.9 ng/mL respectively). Autoimmune or immunologic diseases (AIDs) were present in 32/34 patients. Stomach pathology showed premalignant or malignant lesions in 26 patients, including gastric neuroendocrine tumors (GNETs) in 6 and adenocarcinoma in 1. One patient presented with neurologic symptoms and subacute combined degeneration of the posterior column of the spinal cord.

CONCLUSION

PA should be suspected in patients with unexplained anemia or neurologic symptoms. The diagnosis of PA relies on fasting gastrin and gastric auto-antibody testing, in addition to hematologic evaluation. EGD with measurement of gastric pH and biopsies of the fundus and antrum identifies patients with achlorhydria, atrophic gastritis, and premalignant and malignant stomach lesions. EGD surveillance of patients with high-risk stomach lesions is recommended.

ABBREVIATIONS

AID = autoimmune or immunologic disease; EGD = esophagogastroduodenoscopy; GNET = gastric neuroendocrine tumor; IFBA = intrinsic factor blocking antibody; PA = pernicious anemia; PCA = parietal cell antibody; T1D = type 1 diabetes.

Linked colour imaging benefits the endoscopic diagnosis of distal gastric diseases

Gastric diseases are common in China, and gastroduodenoscopy could provide accurate diagnoses. Our previous study verified that linked colour imaging (LCI) can improve endoscopic diagnostic accuracy. This study aimed for the first time to establish an LCI-based endoscopic model called colour-microstructure-vessel (CMV) criteria and validated its clinical feasibility for detecting distal gastric diseases manifested as red mucosal lesions under endoscopy in a cohort of 62 patients. Colour features were extracted from the endoscopic images and categorized into 3 types. Colour type 1 was a typical red; Colour type 2 was red ringed with purple and Colour type 3 was red with yellow in the centre and purple around the periphery, allowing for predicting chronic nonatrophic gastritis, chronic atrophic gastritis and gastric cancer. The sensitivity, specificity and Youden index of Colour type 3 with abnormal M or V for gastric cancer were 100.0%, 98.2% and 98.2%. The kappa values for intra-observer and inter-observer agreement for predicting the pathology were 0.834 and 0.791 for experienced endoscopists and 0.788 and 0.732 for endoscopy learners, and these values were comparable regardless of the experience of the endoscopists (P > 0.05). These findings support that the CMV criteria are a promising model for accurate endoscopic diagnosis.

Long-term clinical outcomes of laparoscopy-assisted distal gastrectomy versus open distal gastrectomy for early gastric cancer: A comprehensive systematic review and meta-analysis of randomized control trials

The objective of this study was to compare long-term surgical outcomes and complications of laparoscopy-assisted distal gastrectomy (LADG) with open distal gastrectomy (ODG) for the treatment of early gastric cancer (EGC) based on a review of available randomized controlled trials (RCTs) evaluated using the Cochrane methodology.RCTs comparing LADG and ODG were identified by a systematic literature search in PubMed, Cochrane Library, MEDLINE, EMBASE, Scopus, and the China Knowledge Resource Integrated Database, for papers published from January 1, 2003 to July 30, 2015. Meta-analyses were performed to compare the long-term clinical outcomes.Our systematic literature search identified 8 eligible RCTs including 732 patients (374 LADGs and 358 ODGs), with low overall risk of bias. Long-term mortality and relapse rate were comparable for both techniques. The long-term complication rate was 8.47% in LADG groups and 13.62% in the ODG group, indicating that LADG was associated with lower risk for long-term complications (RR = 0.63; 95%CI = 0.39-1.00; P = 0.03).In the treatment of EGC, LADG lowered the rate of long- and short-term complications and promoted earlier recovery, with comparable oncological outcomes to ODG.

Detection of gastric cancer using transabdominal ultrasonography is associated with tumor diameter and depth of invasion

Gastric cancer is occasionally diagnosed using transabdominal ultrasonography (US) during screening or investigation of patients with abdominal symptoms. Therefore, the present study analyzed the association of the tumor diameter, pathological T (pT) staging and depth of invasion with the detection of gastric cancer using US. Patient records were analyzed retrospectively and 13 patients were enrolled, who underwent US screening prior to endoscopic mucosal resection, endoscopic submucosal dissection or surgery. In total, 5 patients were diagnosed with gastric cancer using US (positive detection group), while US was unable to detect the gastric cancer in 8 patients (negative detection group). The tumor diameter and depth of invasion were determined by pathologists. One-way analysis of variance or the χ² test was performed. Wall thickness in gastric cancer cases ranged between 7 and 20 mm (mean, 12.2±5.9 mm), as measured using abdominal US. The hemoglobin level was significantly lower in the positive detection patients compared with the negative detection patients (P=0.0455). In addition, the diameters of the gastric wall in the negative and positive detection patients were 24.5±16.4 and 54.4±26.2 mm, respectively (P=0.0266). These results indicate that gastric cancer in the positive detection patients were at a more advanced-stage compared with that in the negative detection patients. Furthermore, gastric cancer with a stage over pT2 was diagnosed using abdominal US (P=0.0242), whereas stage pT1a gastric cancer was not detected by abdominal US. Gastric tumors invading deeper than the submucosa were diagnosed using US (P=0.0242). However, the gastric cancer cases limited to the mucosa remained undetected. In conclusion, the detection of gastric cancer correlated well with the tumor diameter, pT staging and depth of invasion.

Level of circulated microRNA-421 in gastric carcinoma and related mechanisms

As one of the most popular and deadly malignant tumors, gastric cancer still has difficulty in early-diagnosis. Recently the level of circulated DNA related with tumors can be used for diagnosis. MicroRNA-421 (miR-421) has been found to be up-regulated in tumor cells. Whether peripheral miR-421 can be used as a marker for diagnosis of gastric carcinoma, however, remains unclear. The expression level of miR-421 in both gastric cancer and normal people were firstly quantified. We then performed in vitro transfection of gastric carcinoma cell line to potentiate or silence miR-421 level. Cell apoptosis and apoptotic protein levels were quantified by flow cytometry and Western blotting, respectively. MiR-421 level in the peripheral blood of gastric cancer patients was significantly elevated. In gastric cancer cell line, the up-regulation of miR-421 significantly inhibited cell apoptosis. The silencing of miR-421 promoted cell apoptosis. Such anti-apoptotic role of miR-421 was accomplished by inhibiting caspase 3, up-regulating Bcl-2 and inhibiting Bax. MiR-421 was up-regulated in both tumor tissue and peripheral blood, and can modulate cell apoptosis. Circulated miR-421 can work as a serological marker for early diagnosis of gastric cancer.

Highlights from the 52nd Seminar of the Korean Society of Gastrointestinal Endoscopy

In this July issue of Clinical Endoscopy, state-of-the-art articles selected from the lectures delivered during the 52nd Seminar of the Korean Society of Gastrointestinal Endoscopy (KSGE) on March 29, 2015 are covered, focusing on highlighted educational contents relevant to either diagnostic or therapeutic gastrointestinal (GI) endoscopy. Our society, the KSGE, has continued to host this opportunity for annual seminars twice a year over the last 26 years and it has become a large-scale prestigious seminar accommodating over 4,000 participants. Definitely, the KSGE seminar is considered as one of the premier state-of-the-art seminars dealing with GI endoscopy, appealing to both the beginner and advanced experts. Lectures, live demonstrations, hands-on courses, as well as an editor school, which was an important consensus meeting on how to upgrade our society journal, Clinical Endoscopy, to a Science Citation Index (Expanded) designation were included in this seminar. The 52nd KSGE seminar consisted of more than 20 sessions, including special lectures, concurrent sessions for GI endoscopy nurses, and sessions exploring new technologies. This is a very special omnibus article to highlight the core contents divided into four sessions: upper GI tract, lower GI tract, pancreatobiliary system, and other specialized sessions.