Basic principles and practice of gastric cancer screening using high-definition white-light gastroscopy: Eyes can only see what the brain knows

The endoscopic model for gastric carcinogenesis and Helicobacter pylori infection: A potential visual mind-map during gastroscopy examination

Helicobacter pylori (Hp) is the main trigger of chronic gastric atrophy and the main leading cause of gastric cancer. Hp infects the normal gastric mucosa and can lead to chronic inflammation, glandular atrophy, intestinal metaplasia, dysplasia and finally adenocarcinoma. Chronic inflammation and gastric atrophy associated with Hp infection appear initially in the distal part of the stomach (the antrum) before progressing to the proximal part (the corpus-fundus). In recent years, endoscopic developments have allowed for the characterization of various gastric conditions including the normal mucosa (pyloric/fundic gland pattern and regular arrangement of collecting venules), Hp-related gastritis (Kyoto classification), glandular atrophy (Kimura-Takemoto classification), intestinal metaplasia (Endoscopic Grading of Gastric Intestinal Metaplasia), and dysplasia/adenocarcinoma (Vessel plus Surface classification). Despite being independent classifications, all these scales can be integrated into a single model: the endoscopic model for gastric carcinogenesis. This model would assist endoscopists in comprehending the process of gastric carcinogenesis and conducting a systematic examination during gastroscopy. Having this model in mind would enable endoscopists to promptly recognize the implications of Hp infection and the potential patient's risk of developing gastric cancer.

Analysis of the detection rate and clinical characteristics of early gastric cancer by painless gastroscopy and ordinary gastroscopy

OBJECTIVE

To investigate the difference of early gastric cancer (EGC) detection rate and endoscopic characteristics between painless and ordinary electronic gastroscopy, and summarize the clinical data of gastric cancer (GC) patients.

METHODS

Clinical data of 72,000 patients who underwent gastroscopy in the First People Hospital of Huzhou (Zhejiang, China) from January 2016 to December 2021 were retrospectively analyzed. The patients were divided into painless gastroscopy group (observation group, 36,000 cases) and ordinary gastroscopy group (control group, 36,000 cases) according to the examination methods. The detection rate of EGC between the 2 groups and the endoscopic characteristics of EGC lesions between the 2 groups were compared, and the clinical data of GC were summarized.

RESULTS

Painless gastroscopy is safer than ordinary gastroscopy. The detection rate of GC and EGC in the observation group was significantly higher than that in the control group (P < .05); the difference between the 2 groups in the detection rate of advanced GC was not statistically significant. The average length of EGC lesions in the observation group was significantly shorter than that in the control group (P < .05). The proportion of EGC with lesion length <2.0 cm in the observation group was significantly higher than that in the control group (P < .05). The proportion of EGC lesions with type II morphology, normal or pallor mucosal color, and no rupture in mucosa in the control group were significantly lower than that in the observation group, respectively (P < .05). The proportion of EGC distributed in the cardia, fundus and corpus was higher in the observation group than in the control group (P < .05). The incidence of helicobacter pylori (HP) infection, precancerous diseases, first-degree relatives of GC patients, and risk factors in patients with GC was significantly higher than that in non-GC patients (P < .05), multivariate logistic regression analysis showed that these were independent influencing factors for the occurrence of GC.

CONCLUSION

Painless gastroscopy can effectively improve the screening and diagnostic efficiency of EGC, especially for EGC lesions that are not easy to expose the site, small in size, superficial, without obvious mucosal color change or without mucosal breakage. Therefore, the value of painless gastroscopy in EGC screening is worth further promotion and research.

Curative criteria for endoscopic treatment of gastric cancer

Endoscopic treatment, particularly endoscopic submucosal dissection, has become the primary treatment for early gastric cancer. A comprehensive optical assessment, including white light endoscopy, image-enhanced endoscopy, and magnification, are the cornerstones for clinical staging and determining the resectability of lesions. This paper discusses factors that influence the indication for endoscopic resection and the likelihood of achieving a curative resection. Our review stresses the critical need for interpreting the histopathological report in accordance with clinical guidelines and the imperative of tailoring decisions based on the patients' and lesions' characteristics and preferences. Moreover, we offer guidance on managing complex scenarios, such as those involving non-curative resection. Finally, we identify future research avenues, including the role of artificial intelligence in estimating the depth of invasion and the urgent need to refine predictive scores for lymph node metastasis and metachronous lesions.

Optimal timing of simethicone administration prior to upper endoscopy: A multicenter, single-blind, randomized controlled trial

Background and study aims Simethicone is useful as premedication for upper endoscopy because of its antifoaming effects. We aimed to evaluate the effect of timing of simethicone administration on mucosal visibility. Patients and methods In this multicenter, randomized, endoscopist-blinded study, patients scheduled for upper endoscopy were randomized to receive 40 mg simethicone at the following time points prior to the procedure: 20 to 30 minutes (early group), 0 to 10 minutes (late group) or 20 mg simethicone at both time points (split-dose group). Images were taken from nine predefined locations in the esophagus, stomach, and duodenum before endoscopic flushing. Each image was scored on mucosal visibility by three independent endoscopists on a 4-point scale (lower scores indicating better visibility), with adequate mucosal visibility defined as a score ≤ 2. Primary outcome was the percentage of patients with adequate total mucosal visibility (TMV), reached if all median subscores for each location were ≤ 2. Results A total of 386 patients were included (early group: 132; late group: 128; split-dose group: 126). Percentages of adequate TMV were 55%, 42%, and 61% in the early, late, and split-dose group, respectively ( P < 0.01). Adequate TMV was significantly higher in the split-dose group compared to the late group ( P < 0.01), but not compared to the early group ( P = 0.29). Differences between groups were largest in the stomach, where percentages of adequate mucosal visibility were higher in the early (68% vs 53%, P = 0.03) and split-dose group (69% vs 53%, P = 0.02) compared to the late group. Conclusions Mucosal visibility can be optimized with early simethicone administration, either as a single administration or in a split-dose regimen.

Variation in the rate of detection of minute and small early gastric cancers at diagnostic endoscopy may reflect the performance of individual endoscopists

OBJECTIVE

The documented variation in gastric cancer (GC) detection among endoscopists has often been dismissed as a coincidental artefact of the low incidence of gastric neoplasms; it is not considered associated with differences in physicians' performance of the esophagogastroduodenoscopy procedure. This study is to confirm whether significant variations among endoscopists in early GC detection suggest the individual performance of the upper endoscopy.

DESIGN

A retrospective observational study at a single centre in Japan assessed the results of 218 early GCs detected during 25 688 routine esophagogastroduodenoscopies by 12 endoscopists. The main outcome was the rate of early GC detection for each endoscopist under the same circumstances. Other measures included the major diameters and locations of the lesions, Helicobacter pylori infection status, and baseline patient characteristics that could affect the prevalence of GC.

RESULTS

The early GC detection rates exhibited wide variation among endoscopists (0.09%-2.87%) despite performing routine esophagogastroduodenoscopies in a population with a similar background. Endoscopists were assigned to a low-detection group (n=6; detection rate: 0.47% (range: 0.09%-0.55%)) and a high-detection group (n=5; detection rate: 0.83% (range: 0.63%-1.12%)), with the single highest detector analysed separately due to his distinct detection rate (2.87%). Endoscopists in the high-detection group had better detection rates for minute (major diameter ≤5 mm) and small (major diameter 6-10 mm) GCs than the low-detection group (0.19%/0.23% vs 0.085%/0.098%). These differences were significant (p<0.01), although there were no significant differences in detection of larger tumours (major diameter ≥11 mm; 0.40% vs 0.28%; p=0.13). The tumour location and H. pylori status were similar in the low-detection group, high-detection group and for the highest detector.

CONCLUSION

Significant variation in the detection of hard-to-find, smaller GCs may reflect individual performance of the examination.

Prospective cohort study to evaluate premedication with simethicone and n-acetilcysteine for upper diagnostic gastrointestinal endoscopy

INTRODUCTION

The use of premedication for upper gastrointestinal endoscopy (UGE) is not widely established in western countries. The primary aim of the study was to compare gastric visibility according to the total visibility score (TVS). The secondary aim was to assess complications, diagnostic yield, endoscopic procedure time, sedation dose and patient satisfaction.

METHODS

A single center prospective cohort study was performed of consecutive adults undergoing an UGE in the afternoon working shift. After completing enrolment in the control group, patients were administered 200 mg simethicone and 500 mg N-acetylcysteine diluted in 100 ml of water >15 minutes before the procedure. All procedures were recorded and a single, blinded endoscopist evaluated the TVS after recruitment of both cohorts. Patient satisfaction was evaluated using the Spanish translation of the American Society of Gastrointestinal Endoscopy satisfaction questionnaire.

RESULTS

205 patients were included in the study, 103 females (50.2%) with a median age of 54.8-years (IQR: 41.2-65.2). 104 were enrolled to the control group and 101 to the intervention group. Patients receiving premedication presented a higher rate of adequate (74.3% vs 45.2; difference 95% CI: 16,3-41,9%, p<0.001) and excellent gastric visibility (23.8% vs 7.7%; difference 95% CI: 6,3-25,8%, p=0.002). Propofol dose was similar, although the median procedure time was lower in the group of no intervention [5 (IQR: 4-7) vs 6 minutes (IQR: 5-7); p=0.03]. Procedure related adverse events were similar, except that patient without premedication experienced more nausea episodes. Major and minor endoscopic findings and the satisfaction questionnaire showed no differences between both groups.

CONCLUSION

Patients receiving premedication with simethicone and N-acetylcysteine had a better gastric visibility score, without any increase in adverse events or affecting the patients' satisfaction.

A system based on deep convolutional neural network improves the detection of early gastric cancer

Background

Early gastric cancer (EGC) has a high survival rate, but it is difficult to diagnosis. Recently, artificial intelligence (AI) based on deep convolutional neural network (DCNN) has made significant progress in the field of gastroenterology. The purpose of this study was to establish a DCNN assist system to improve the detection of EGC.

Methods

3400 EGC and 8600 benign images were collected to train the DCNN to detect EGC. Subsequently, its diagnostic ability was compared to that of endoscopists using an independent internal test set (ITS, including 1289 images) and an external test set (ETS, including 542 images) come from three digestive center.

Results

The diagnostic time of DCNN and endoscopists were 0.028s, 8.05 ± 0.21s, 7.69 ± 0.25s in ITS, and 0.028s, 7.98 ± 0.19s, 7.50 ± 0.23s in ETS, respectively. In ITS, the diagnostic sensitivity and accuracy of DCNN are 88.08%(95% confidence interval,95%CI,85.24%-90.44%), 88.60% (95%CI,86.74%-90.22%), respectively. In ETS, the diagnostic sensitivity and accuracy are 92.08% (95%CI, 87.91%- 94.94%),92.07%(95%CI, 89.46%-94.08%),respectively. DCNN outperformed all endoscopists in ETS, and had a significantly higher sensitivity than the junior endoscopists(JE)(by18.54% (95%CI, 15.64%-21.84%) in ITS, also higher than JE (by21.67%,95%CI, 16.90%-27.32%) and senior endoscopists (SE) (by2.08%, 95%CI, 0.75%-4.92%)in ETS. The accuracy of DCNN model was higher (by10.47%,95%CI, 8.91%-12.27%) than that of JE in ITS, and also higher (by14.58%,95%CI, 11.84%-17.81%; by 1.94%,95%CI,1.25%-2.96%, respectively) than JE and SE in ETS.

Conclusion

The DCNN can detected more EGC images in a shorter time than the endoscopists. It will become an effective tool to assist in the detection of EGC in the near future.

Outcome of Nursing Based on Health Belief United with Knowledge, Belief, and Practice Mode on Gastroscopy of Patients with Gastric Cancer

Aim

If gastric cancer can be detected through early screening, and scientific and reasonable intervention methods can be selected in time, the condition can be effectively controlled. Routine nursing has been unable to obtain satisfactory results, and the effect on improving the compliance of the examiner is not outstanding. The research aims to estimate the outcome of nursing based on health belief combined with knowledge, belief, and practice on gastroscopy in patients with gastric cancer.

Methods

126 patients with clinically diagnosed gastric cancer in the Number Two Hospital of Baoding from May 2020 to May 2022 were randomly divided into belief guidance group and mode group, with 63 instances each. The mode group was intervened via the mode of knowledge, belief, and practice, and the belief guidance group was intervened via the nursing based on health belief on the basis of the mode group. Before and after the nursing, the health belief, examination compliance, inappropriateness, and negative emotion in different time periods were contrasted between the two groups.

Results

After the nursing, the scores of health belief scale in the belief guidance group were enhanced than those in the mode group; the compliance rate of the belief guidance group was markedly enhanced than that of the mode group, and the inappropriateness during the insertion and examination was lower than that of the mode group; the scores of self-rating anxiety scale (SAS) and self-rating depression scale (SDS) in the two groups preinsertion and postnursing were markedly lower than those in the mode group.

Conclusion

Nursing based on health belief guidance united with knowledge, belief, and practice mode nursing can advance the health belief and compliance of gastroscopy in patients with gastric cancer, reduce discomfort, and effectively advance the negative emotions of patients. It is worthy of clinical application.

Improved detection of early gastric cancer with linked color imaging using an ultrathin endoscope: a video-based analysis

Background and study aims  Ultrathin endoscopy causes a minimal gag reflex and has minimal effects on cardiopulmonary function. Linked color imaging (LCI) is useful for detection of malignancies in the digestive tract. The aim of this study was to clarify whether LCI with ultrathin endoscopy facilitates detection of early gastric cancer (EGC) despite its lower resolution compared with high-resolution white light imaging (WLI) with standard endoscopy. Patients and methods  This was a retrospective analysis with prospectively collected video, including consecutive 166 cases of EGC or gastric atrophy alone. Ninety seconds of screening video was collected using standard and ultrathin endoscopes with both WLI and LCI for each case. Three expert endoscopists assessed each video and the sensitivity of detecting EGC calculated. Color difference calculations were performed. Results  Sensitivities using ultrathin WLI, ultrathin LCI, standard WLI, and standard LCI for the identification of cancer were 66.0 %, 80.3 %, 69.9 %, and 84.0 %, respectively. The color difference between malignant lesions and surrounding mucosa with ultrathin LCI and standard LCI were significantly higher than using ultrathin WLI or standard WLI, supported subjectively by the visibility score. Ultrathin LCI color difference and visibility score were significantly higher than standard WLI. Conclusions  LCI with a low-resolution ultrathin endoscope is superior to WLI with a high-resolution standard endoscope for gastric cancer screening. This suggests that the high color contrast between EGC and the surrounding mucosa is more important than high-resolution images.

Gastroenterologists' attitudes on the detection and management of gastric premalignant conditions: results of a nationwide survey in Spain

INTRODUCTION

Gastric premalignant conditions (GPC) surveillance has been proposed to improve the prognosis of gastric cancer (GC), but the early GC detection rate remaining low, and missing GC during an esophago-gastro-duodenoscopy is still a problem. We aimed to explore the gastroenterologists' attitudes on the detection and management of GPC.

METHODS

A cross-sectional study was designed based on a survey among gastroenterologists from Asociación Española de Gastroenterología.

RESULTS

The participation rate was 12% (146/1243). Eighty-one percent worked at secondary or tertiary-care hospitals with the capability to perform mucosectomy (80%), but with a lesser availability of endoscopic submucosal dissection (35%). Most respondents had high-definition endoscopes (88%), and virtual chromoendoscopy (86%), but during performing an upper endoscopy, 34% never or rarely use chromoendoscopy, and 73% apply a biopsy protocol often/very often when atrophy or intestinal metaplasia (IM) is suspected. Half of the respondents self-reported their ability to recognize atrophy or IM ≤7 (on a scale from 0 to 10), whereas ≤6 for dysplasia or early GC. Helicobacter pylori infection is eradicated and verified by ≥90%. Endoscopic surveillance of atrophy/IM is performed by 62%. An immediate endoscopy for dysplasia is not always performed. For low-grade dysplasia, 97.6% consider endoscopic management, but for high-grade dysplasia, 23% regard gastric surgery.

CONCLUSION

There is a wide variability in the detection and management of GPC among Spanish gastroenterologists, and compliance with guidelines and biopsy protocols could be improved. Performance of high-quality gastroscopies including use of virtual chromoendoscopy, that might allow an improvement in the GPC detection, needs also to be generalized.

Application of convolutional neural network in detecting and classifying gastric cancer

Gastric cancer (GC) is the fifth most common cancer in the world, and at present, esophagogastroduodenoscopy is recognized as an acceptable method for the screening and monitoring of GC. Convolutional neural networks (CNNs) are a type of deep learning model and have been widely used for image analysis. This paper reviews the application and prospects of CNNs in detecting and classifying GC, aiming to introduce a computer-aided diagnosis system and to provide evidence for subsequent studies.

Pre-Endoscopy Drink of Simethicone and N-Acetylcysteine Significantly Improves Visualization in Upper Gastrointestinal Endoscopy

Introduction With the advancements in diagnostic and therapeutic upper gastrointestinal endoscopy (UGIE), clear mucosal visualization is essential to ensure optimal outcomes. Though routinely followed in Japan and Korea, pre-endoscopic preparation is seldom used in India. We evaluated the efficacy of a pre-endoscopic drink of N-acetylcysteine (NAC) and simethicone in improving mucosal visibility during UGIE.

Patients and Methods This study was a retrospective, investigator blind study with a case–control study design. Cases included patients who received a pre-endoscopy drink of NAC and simethicone in 100 mL water administered 10 to 30 minutes prior to UGIE. Controls only had mandatory fasting for 6 to 8 hours prior to UGIE. Propensity score matching was done to ensure comparability between the groups. Digital images were taken at six standard landmarks during UGIE and stored. A blinded investigator subsequently analyzed the images and rated the mucosal visibility on a 3-point scale. The difference in the mean mucosal visibility between the cases and controls was compared.

Results Mean mucosal visibility during UGIE was significantly better using NAC with simethicone as compared with no preparation at esophagus (1.14 [0.37] vs. 1.47 [0.62], p < 0.05), gastric fundus (1.10 [0.30] vs. 1.55 [0.64], p < 0.05), gastric body (1.22 [0.50] vs. 1.62 [0.73], p < 0.05), gastric antrum (1.13 [0.37] vs. 1.47 [0.62], p < 0.05), and duodenal bulb (1.13 [0.34] vs. 1.33 [0.56], p < 0.05). In distal duodenum, though visibility improved with NAC with simethicone, the difference was insignificant. There were no adverse events related to the pre-endoscopy drink.

Conclusion A pre-endoscopy drink of NAC with simethicone can significantly improve mucosal visibility during UGIE. It is safe, cheap, easily available and maybe considered for routine utilization for ensuring optimal endoscopic outcomes.

Premedication with reformulated simethicone and sodium bicarbonate improves mucosal visibility during upper gastrointestinal endoscopy: a double-blind, multicenter, randomized controlled trial

Background

The reformulated simethicone emulsion from Berlin Chemical AG might develop white flocculate precipitate covering the gastric mucosa when used before esophagogastroduodenoscopy (EGD). We aim to investigate whether combining the reformulated simethicone emulsion with 5% sodium bicarbonate solution could prevent the development of white precipitate and improve visibility during EGD.

Methods

Our clinical study involved 523 patients. They were randomly assigned to two groups. In Group A, patients received a warm solution containing 30 ml 5% sodium bicarbonate solution and 15 ml reformulated simethicone emulsion. In Group B, patients received 45 ml 40 °C lukewarm water. Visibility scores were recorded and analyzed. Flushes, volume of flush water, overall time taken for EGD and complications during or after the procedure were also recorded.

Results

We found that no white precipitate was observed during EGD in Group A. Moreover, visibility scores in Group A were significantly lower (P < 0.01). Patients in Group A had fewer flushes (P < 0.01) and smaller volume of flush water (P < 0.01). In addition, the overall time taken for the EGD procedure was significantly shorter in Group A (P < 0.01). The percentage of patients who had no adverse response was significantly higher in Group A than in Group B (P < 0.01).

Conclusions

Premedication with a mixed solution of 15 ml reformulated simethicone emulsion and 30 ml 5% sodium bicarbonate solution can prevent the development of white precipitate, substantially enhancing mucosal visibility safely.

Trial registration: The registered name of the trial is “Efficacy of using premedication with reformulated simethicone emulsion during upper gastrointestinal endoscopy examination”. Its Current Controlled Trials number is ChiCTR1900021689. Its date of registration is 11 September 2019. Retrospectively registered, http://www.medresman.org.cn/uc/sindex.aspx.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-021-01623-w.

Detecting early gastric cancer: Comparison between the diagnostic ability of convolutional neural networks and endoscopists

OBJECTIVES

Detecting early gastric cancer is difficult, and it may even be overlooked by experienced endoscopists. Recently, artificial intelligence based on deep learning through convolutional neural networks (CNNs) has enabled significant advancements in the field of gastroenterology. However, it remains unclear whether a CNN can outperform endoscopists. In this study, we evaluated whether the performance of a CNN in detecting early gastric cancer is better than that of endoscopists.

METHODS

The CNN was constructed using 13,584 endoscopic images from 2639 lesions of gastric cancer. Subsequently, its diagnostic ability was compared to that of 67 endoscopists using an independent test dataset (2940 images from 140 cases).

RESULTS

The average diagnostic time for analyzing 2940 test endoscopic images by the CNN and endoscopists were 45.5 ± 1.8 s and 173.0 ± 66.0 min, respectively. The sensitivity, specificity, and positive and negative predictive values for the CNN were 58.4%, 87.3%, 26.0%, and 96.5%, respectively. These values for the 67 endoscopists were 31.9%, 97.2%, 46.2%, and 94.9%, respectively. The CNN had a significantly higher sensitivity than the endoscopists (by 26.5%; 95% confidence interval, 14.9-32.5%).

CONCLUSION

The CNN detected more early gastric cancer cases in a shorter time than the endoscopists. The CNN needs further training to achieve higher diagnostic accuracy. However, a diagnostic support tool for gastric cancer using a CNN will be realized in the near future.

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.

Gastric cancer missed at esophagogastroduodenoscopy in a well-defined Spanish population

BACKGROUND

Although esophagogastroduodenoscopy (EGD) is the standard procedure for the diagnosis of gastric cancer (GC), some GCs are missed. There are no published data on the missed rate of GC in Spain.

AIMS

To determine the frequency and characteristics of missed GCs and assess the quality of the EGD in a specific population with GC.

METHODS

Records of all patients diagnosed with gastric adenocarcinoma between 2012 and 2016 in a defined geographic area were reviewed. Missed GC was defined as a case with a prior negative EGD for cancer. Quality indicators from the prior EGDs were measured.

RESULTS

From 212 cases of GC, 25 cases were excluded. Seventeen out of 187 patients had a prior EGD (9.1%). Twelve of those 17 missed GC had a prior EGD with some abnormal findings. In 6 of them, biopsies were taken. Survival was no different between patients with missed and non-missed GC. Quality indicators that failed to meet standards were recording time, image documentation, and a protocol of biopsies.

CONCLUSIONS

Missed GC in an EGD in a defined population in Spain is not uncommon (9.1%). The endoscopist is an important factor in missed GC due to lack of adequate detection and sampling error. Compliance with performance of quality indicators could reduce missed GC.

How I do it: Flexible 3-D endoscope for endoscopic submucosal dissection

Endoscopic submucosal dissection (ESD) is technically challenging as a result of a lack of depth perception. The present article investigated the 3-D endoscope for carrying out ESD and translated the technique from bench to clinical use. In a preclinical porcine experiment, ESD using a 3-D endoscope was compared between an experienced and a novice endoscopist. All ESD were completed without perforation. Median operative time per surface area was significantly lower for the experienced endoscopist than for the novice (197.9 s/cm² vs 434.7 s/cm² ; P = 0.05). The second part was a prospective clinical experience to evaluate use of the 3-D endoscope for carrying out ESD. Ten patients received ESD using the 3-D endoscope. Four patients had gastric ESD, two had duodenal ESD and four had sigmoid and rectal ESD. There were no complications, whereas ESD failed in one patient who had gastric neoplasia at anastomosis. Mean operative time was 99.4 min, and operative time per surface area resection was 391 s/cm² . The operating endoscopist did not complain of motion sickness, whereas the assistants had some dizziness upon prolonged ESD procedure. This study showed that carrying out ESD was safe and effective using a 3-D endoscope with an excellent 3-D view enhancing depth perception. Future study should be conducted to compare 3-D against 2-D endoscopes for ESD.

Utility of a standardized training program for endoscopic diagnosis of early gastrointestinal neoplasia

Background and study aims  Image enhanced endoscopy (IEE) allows endoscopists to improve recognition and characterization of gastrointestinal neoplasia. The Asian Novel Bio-Imaging and Intervention Group (ANBIG) conducted a standardized training program in endoscopic diagnosis and treatment of early gastrointestinal cancers in Asia. We embarked on a study to investigate the effect of this module on endoscopic diagnosis of early gastrointestinal neoplasia. Methods  This prospectively collected database was from workshops conducted on training for endoscopic diagnosis of early gastrointestinal neoplasia. All workshops were conducted in a standardized format, which included a pretest, a learning phase consisting of didactic lectures, case discussion, and live demonstration followed by a post-test to assess knowledge gained. The pretest and post-training tests were standardized questions addressing four domains, including basic knowledge of imaging and diagnosis of esophageal, gastric, and colonic neoplasia. Results  From November 2013 to November 2016, 41 ANBIG workshops were conducted in 13 countries. A total of 1863 delegates and 40 faculty participated in these workshops. Of the delegates, 627 completed both tests. There was a significant improvement after training in all domains of the tests. There was a trend in general lack of knowledge across all domains for delegates from "low" healthcare cost countries before training. All delegates demonstrated significant improvement in knowledge of all domains after the workshop irrespective of whether they were from "high" or "low" healthcare cost per capita countries. Conclusion  A standardized teaching program on IEE improved the diagnostic ability and quality of endoscopists in recognizing early gastrointestinal neoplasia in Asia.

The effect of using simethicone with or without N-acetylcysteine before gastroscopy: A meta-analysis and systemic review

BACKGROUND/AIM

To assess the efficacy and safety of simethicone with or without N-acetylcysteine (NAC) as premedications before gastroscopy.

MATERIALS AND METHODS

We searched EMBASE, PubMed, Cochrane library and Web of Science database for randomized clinical controlled trials regarding simethicone ± NAC as oral drinking agents before gastroscopy. Statistical software RevMan5.3 was used for statistical analysis.

RESULTS

Ten randomized clinical trials that fulfilled the inclusion criteria were further pooled into a meta-analysis, which included 5,750 patients. The rate of positive findings in simethicone plus NAC group was higher than that in water group (risk ratio [RR] =1.31, 95%CI: 1.12-1.53, P = 0.0006) with high level of evidence. There was no significant difference on the rate of positive findings when comparing simethicone with simethicone plus NAC (RR = 1.02, 95%CI: 0.90-1.16, P = 0.71) and with water (RR = 1.13, 95%CI: 0.82-1.55, P = 0.46), respectively. Simethicone plus NAC showed better total mucosal visibility score than simethicone alone (MD = -0.14 (-0.25, -0.03), P = 0.01) without obvious heterogeneity. Both simethicone plus NAC and simethicone alone offer more benefit than water. The procedure time in simethicone group was shorter than that in water group (MD = -1.23 (-1.51, -0.96), P < 0.00001). Regarding adverse events, there was no significant difference in simethicone and water group (RR = 0.45, 95%CI: 0.2-1.0, P = 0.05, I² = 0%).

CONCLUSIONS

As premedication of gastroscopy, simethicone plus NAC offers more benefit on positive findings and total mucosal visibility score.

Bacterial endosymbiont Cardinium cSfur genome sequence provides insights for understanding the symbiotic relationship in Sogatella furcifera host

BACKGROUND

Sogatella furcifera is a migratory pest that damages rice plants and causes severe economic losses. Due to its ability to annually migrate long distances, S. furcifera has emerged as a major pest of rice in several Asian countries. Symbiotic relationships of inherited bacteria with terrestrial arthropods have significant implications. The genus Cardinium is present in many types of arthropods, where it influences some host characteristics. We present a report of a newly identified strain of the bacterial endosymbiont Cardinium cSfur in S. furcifera.

RESULT

From the whole genome of S. furcifera previously sequenced by our laboratory, we assembled the whole genome sequence of Cardinium cSfur. The sequence comprised 1,103,593 bp with a GC content of 39.2%. The phylogenetic tree of the Bacteroides phylum to which Cardinium cSfur belongs suggests that Cardinium cSfur is closely related to the other strains (Cardinium cBtQ1 and cEper1) that are members of the Amoebophilaceae family. Genome comparison between the host-dependent endosymbiont including Cardinium cSfur and free-living bacteria revealed that the endosymbiont has a smaller genome size and lower GC content, and has lost some genes related to metabolism because of its special environment, which is similar to the genome pattern observed in other insect symbionts. Cardinium cSfur has limited metabolic capability, which makes it less contributive to metabolic and biosynthetic processes in its host. From our findings, we inferred that, to compensate for its limited metabolic capability, Cardinium cSfur harbors a relatively high proportion of transport proteins, which might act as the hub between it and its host. With its acquisition of the whole operon related to biotin synthesis and glycolysis related genes through HGT event, Cardinium cSfur seems to be undergoing changes while establishing a symbiotic relationship with its host.

CONCLUSION

A novel bacterial endosymbiont strain (Cardinium cSfur) has been discovered. A genomic analysis of the endosymbiont in S. furcifera suggests that its genome has undergone certain changes to facilitate its settlement in the host. The envisaged potential reproduction manipulative ability of the new endosymbiont strain in its S. furcifera host has vital implications in designing eco-friendly approaches to combat the insect pest.

Application of artificial intelligence using a convolutional neural network for detecting gastric cancer in endoscopic images

BACKGROUND

Image recognition using artificial intelligence with deep learning through convolutional neural networks (CNNs) has dramatically improved and been increasingly applied to medical fields for diagnostic imaging. We developed a CNN that can automatically detect gastric cancer in endoscopic images.

METHODS

A CNN-based diagnostic system was constructed based on Single Shot MultiBox Detector architecture and trained using 13,584 endoscopic images of gastric cancer. To evaluate the diagnostic accuracy, an independent test set of 2296 stomach images collected from 69 consecutive patients with 77 gastric cancer lesions was applied to the constructed CNN.

RESULTS

The CNN required 47 s to analyze 2296 test images. The CNN correctly diagnosed 71 of 77 gastric cancer lesions with an overall sensitivity of 92.2%, and 161 non-cancerous lesions were detected as gastric cancer, resulting in a positive predictive value of 30.6%. Seventy of the 71 lesions (98.6%) with a diameter of 6 mm or more as well as all invasive cancers were correctly detected. All missed lesions were superficially depressed and differentiated-type intramucosal cancers that were difficult to distinguish from gastritis even for experienced endoscopists. Nearly half of the false-positive lesions were gastritis with changes in color tone or an irregular mucosal surface.

CONCLUSION

The constructed CNN system for detecting gastric cancer could process numerous stored endoscopic images in a very short time with a clinically relevant diagnostic ability. It may be well applicable to daily clinical practice to reduce the burden of endoscopists.

Use of N-acetylcysteine plus simethicone to improve mucosal visibility during upper GI endoscopy: a double-blind, randomized controlled trial

BACKGROUND AND AIM

Upper GI endoscopy (UGE) is essential for the diagnosis of gastrointestinal diseases. Mucus and bubbles may decrease mucosal visibility. The use of mucolytics could improve visualization. Our aim was to determine whether premedication with simethicone or simethicone plus N-acetylcysteine is effective in improving visibility during UGE.

METHODS

This was a randomized, double-blinded, placebo-controlled trial with 2 control groups: no intervention and water 100 mL (W); and 3 intervention groups: simethicone 200 mg (S); S + N-acetylcysteine (NAC) 500 mg (S+NAC500); and S + NAC 1000 mg (S+NAC1000). The solution was ingested 20 minutes before UGE. Gastric visibility was evaluated in 4 segments with a previously described scale. A score of less than 7 points was defined as adequate visibility (AV). Water volume was used to improve visibility, and adverse reactions were evaluated as a secondary outcome. Multiple group comparison was performed using non-parametric one-way analysis of variance (ANOVA).

RESULTS

Two hundred thirty patients were included in the study, 68% female, mean age 49 years. The most common indication for UGE was epigastric pain/dyspepsia (33%). AV was more frequent in the S+NAC500 and S+NAC1000 groups (65% and 67%) compared with no intervention (44%, P = .044) and water (41%, P = .022). The gastric total visibility scale (TVS) was significantly better in the S+NAC500 and S+NAC1000 groups compared with water (P = .03 and P = .008). Simethicone was not different from no intervention and water. S+NAC1000 required less water volume to improve visibility. No adverse reactions from the study drugs were observed.

CONCLUSIONS

Premedication with S+NAC500 and S+NAC1000 improves visibility during UGE. The use of simethicone did not show improvements in gastric visibility. TVS was worse in patients using water alone. (Clinical trial registration number: NCT 01653171.).

Efficacy and safety of using premedication with simethicone/Pronase during upper gastrointestinal endoscopy examination with sedation: A single center, prospective, single blinded, randomized controlled trial

BACKGROUND AND AIM

To investigate the efficacy and safety of premedication with simethicone/Pronase during esophagogastroduodenoscopy (EGD) with sedation.

METHODS

Six hundred and ten patients were randomly allocated to two groups based on type of premedication given. Premedication used in the control group was 10 mL lidocaine hydrochloride mucilage (LHM, N = 314) and premedication used in the intervention group was 80 mL simethicone/Pronase solution plus 10 mL lidocaine hydrochloride mucilage (SP/LHM, N = 296). EGD was done under sedation. Visibility scores, number of mucosal areas that needed cleansing, water consumption for cleansing, time taken for examination, diminutive lesions, pathological diagnosis, patients' gag reflex and oxygenation (pulse oximetry) were recorded.

RESULTS

SP/LHM has significantly lower total visibility score than LHM (7.978 ± 1.526 vs 6.348 ± 1.097, P < 0.01). During the procedure, number of intragastric areas that needed cleansing and amount of water consumed were significantly less in the SP/LHM than in the LHM group (P < 0.01). In SP/LHM (P = 0.01), endoscopy procedure duration was significantly longer. Although there was no significant difference in rate of detection of diminutive lesions between LHM and SP/LHM, the endoscopist carried out more biopsies in SP/LHM. This led to a higher rate of diagnosis of atrophic gastritis (P = 0.014) and intestinal metaplasia (P = 0.024). There was no significant difference in gag reflex (P = 0.604) and oxygenation during the endoscopy procedure for either group of patients.

CONCLUSION

Routine use of premedication with simethicone/Pronase should be recommended during EGD with sedation.

Location characteristics of early gastric cancer treated with endoscopic submucosal dissection

BACKGROUND AND STUDY AIMS

The timely detection of early gastric cancer (EGC) is important in performing endoscopic submucosal dissection (ESD). We attempted to determine the location characteristics of regions where EGC is frequently detected and analyzed the EGC characteristics associated with that location.

METHODS

We retrospectively reviewed the medical records of patients with EGC treated by ESD between November 2008 and August 2016. We retrospectively investigated and analyzed 647 EGC lesions.

RESULTS

The patients' mean age was 66.7 ± 10.8 years. The patient population was predominantly male (77.1%, 499/647). A well-to-moderately differentiated carcinoma was observed in 97.2% of patients. The common site of carcinoma occurrence was the lower part of the stomach (the antrum and lower third of body, 89.6%). Among the stomach hemispheres, the lesser curvature side was the most frequent site of EGC (43.9%). The posterior side of EGC was more frequent than anterior side of EGC (20.4 vs. 15.6%, respectively). Submucosal invasive EGC was more frequent in the mid-to-upper parts of stomach than lower part of stomach (odds ratio 1.919; confidence interval 1.014-3.623; p = 0.045).

CONCLUSIONS

Most EGCs that are resectable with ESD were found in the lower part and in the lesser curvature of the stomach. The submucosal invasive EGC was more frequent in the mid-to-upper part of stomach.