Updated evidence on endoscopic resection of early gastric cancer from Japan

Clinicopathological factors correlated with lymph node metastasis in gastric cancer: A retrospective cohort study involving 5606 patients

BACKGROUND

The identification of risk factors associated with lymph node metastasis (LNM) in gastric cancer will establish a crucial foundation for the implementation of endoscopic operation and multidisciplinary treatment program.

METHODS

5606 gastric cancer patients with comprehensive clinicopathological data were enrolled through systematic searching and rigorous screening. Of the 5606 patients, 1438 were diagnosed with early gastric cancer (EGC), which would be utilized for further analysis. Subsequently, univariate and multivariate logistic regression analyses were conducted to identified the risk factors.

RESULTS

The rates of LNM in T1a, T1b, T2, T3, T4a, and T4b stage gastric cancer were 7.0%, 19.4%, 48.4%, 77.1%, 83.8%, and 89.6% respectively. Female [odds ratio (OR)=1.559, P=0.032], lower tumor location (OR=1.773, P=0.023), tumor size >2cm (OR=2.007, P<0.001), mixed (OR=2.371, P=0.001) and undifferentiated histological types (OR=2.952, P<0.001), T1b stage (OR=2.041, P<0.001), presence of ulceration (OR=1.758, P=0.027), and lymphovascular invasion (LVI) (OR=5.722, P<0.001) were identified as independent risk factors for LNM in EGC. A nomogram was constructed using appropriate predictors to preoperatively predict the risk of LNM in EGC cases.

CONCLUSIONS

This study identified the clinicopathological factors associated with LNM in EGC and developed a prediction model, thereby facilitating the integration of diverse treatment modalities in managing EGC patients.

Hedgehog signaling-related genomics signature for the accurate progress and prognosis prediction in gastric cancer

The Hedgehog pathway is thought to be closely associated with the progression of GC; however, a specific link between the Hedgehog pathway on the prognosis and immune infiltration of gastric cancer is still lacking. This study collected Hedgehog pathway-related genes. The Hedgehog pathway-related pattern were identified by consensus cluster analysis. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and gene set enrichment analysis (GSEA) were used to identify the biological functions which were significantly altered between predefined Cluster1 and Cluster2 in consensus clustering. The risk model of gastric cancer based on Hedgehog signaling pathway was constructed by univariate and multivariate COX regression, and the nomogram was constructed. The results showed that there were significant differences in the expression of Hedgehog pathway-related genes between the two groups. In addition, the constructed risk model was significantly correlated with the clinical prognosis and immune cell infiltration level of patients with gastric cancer. The model effectively predicted the efficacy of chemotherapy in GC patients and the sensitivity of drug treatment between groups. We systematically revealed the mechanism of Hedgehog pathway in gastric cancer and selected biomarkers with biological significance from a new perspective, providing potential direction for the treatment of gastric cancer.

A monocular SLAM system based on SIFT features for gastroscope tracking

During flexible gastroscopy, physicians have extreme difficulties to self-localize. Camera tracking method such as simultaneous localization and mapping (SLAM) has become a research hotspot in recent years, allowing tracking of the endoscope. However, most of the existing solutions have focused on tasks in which sufficient texture information is available, such as laparoscope tracking, and cannot be applied to gastroscope tracking since gastroscopic images have fewer textures than laparoscopic images. This paper proposes a new monocular SLAM framework based on scale-invariant feature transform (SIFT) and narrow-band imaging (NBI), which extracts SIFT features instead of oriented features from accelerated segment test (FAST) and rotated binary robust independent elementary features (BRIEF) features from gastroscopic NBI images, and performs feature retention based on the response sorting strategy for achieving more matches. Experimental results show that the root mean squared error of the proposed algorithm can reach a minimum of 2.074 mm, and the pose accuracy can be improved by up to 25.73% compared with oriented FAST and rotated BRIEF (ORB)-SLAM. SIFT features and response sorting strategy can achieve more accurate matching in gastroscopic NBI images than other features and homogenization strategy, and the proposed algorithm can also run successfully on real clinical gastroscopic data. The proposed algorithm has the potential clinical value to assist physicians in locating the gastroscope during gastroscopy.

A continuous muscle-sparing advantage of pylorus-preserving gastrectomy for older patients with cT1N0M0 gastric cancer in the middle third of the stomach

In older patients with cT1N0M0 gastric cancer in the middle third of the stomach, LPPG has advantages over LDGB1 in maintaining skeletal muscle mass.

BACKGROUND

Laparoscopic pylorus-preserving gastrectomy (LPPG) for early gastric cancer in the middle third of the stomach is expected to be an alternative procedure to laparoscopic distal gastrectomy (LDG). However, whether LPPG is safe and more useful than LDG in older patients is unclear because of their comorbidities and organ dysfunctions.

METHODS

We retrospectively analyzed the data of consecutive patients aged 75 or over who underwent LDG with Billroth I reconstruction (LDGB1) or LPPG for cT1N0M0 gastric cancer in the middle third of the stomach between 2005 and 2019. After propensity score matching was used to improve the comparability between the LDGB1 and LPPG groups, we compared surgical and postoperative nutritional outcomes, including the postoperative trends of bodyweight (%BW) and skeletal muscle index (%SMI).

RESULTS

A total of 132 patients who underwent LDGB1 (n = 88) and LPPG (n = 44) were collected for this study. No significant difference in postoperative complications was observed. The total protein levels after LPPG were significantly higher than those after LDGB1 for 4 postoperative years. Both %BW and %SMI after LPPG were significantly maintained compared with those after LDGB1 during the first year after surgery. For the subsequent years, %BW after LPPG became similar to that after LDGB1, while %SMI after LPPG was significantly larger than LDGB1 continuously.

CONCLUSIONS

LPPG has a great advantage in maintaining the postoperative skeletal muscle mass as well as the nutritional parameters of older patients. LPPG is expected to be an alternative to LDG in older patients.

Advantages of Function-Preserving Gastrectomy for Older Patients With Upper-Third Early Gastric Cancer: Maintenance of Nutritional Status and Favorable Survival

PURPOSE

The incidence of early gastric cancer is increasing in older patients alongside life expectancy. For early gastric cancer of the upper third of the stomach, laparoscopic function-preserving gastrectomy (LFPG), including laparoscopic proximal gastrectomy (LPG) and laparoscopic subtotal gastrectomy (LSTG), is expected to be an alternative to laparoscopic total gastrectomy (LTG). However, whether LFPG has advantages over LTG in older patients remains unknown.

MATERIALS AND METHODS

We retrospectively analyzed data of consecutive patients aged ≥75 years who underwent LTG, LPG, or LSTG for cT1N0M0 gastric cancer between 2005 and 2019. Surgical and nutritional outcomes, including blood parameters, percentage body weight (%BW) and percentage skeletal muscle index (%SMI) were compared between LTG and LPG or LSTG. Survival outcomes were also compared between LTG and LFPG groups.

RESULTS

A total of 111 patients who underwent LTG (n=39), LPG (n=48), and LSTG (n=24) were enrolled in this study. To match the surgical indications, LTG was further categorized into "LTG for LPG" (LTG-P) and "LTG for LSTG" (LTG-S). No significant differences were identified in the incidence of postoperative complications among the procedures. Postoperative nutritional parameters, %BW and %SMI were better after LPG and LSTG than after LTG-P and LTG-S, respectively. The survival outcomes of LFPG were better than those of LTG.

CONCLUSIONS

LFPG is safe for older patients and has advantages over LTG in terms of postoperative nutritional parameters, body weight, skeletal muscle-sparing, and survival. Therefore, LFPG for upper early gastric cancer should be considered in older patients.

Weakly Supervised Learning for Poorly Differentiated Adenocarcinoma Classification in GastricEndoscopic Submucosal Dissection Whole Slide Images

Objective: Endoscopic submucosal dissection (ESD) is the preferred technique for treating early gastric cancers including poorly differentiated adenocarcinoma without ulcerative findings. The histopathological classification of poorly differentiated adenocarcinoma including signet ring cell carcinoma is of pivotal importance for determining further optimum cancer treatment(s) and clinical outcomes. Because conventional diagnosis by pathologists using microscopes is time-consuming and limited in terms of human resources, it is very important to develop computer-aided techniques that can rapidly and accurately inspect large number of histopathological specimen whole-slide images (WSIs). Computational pathology applications which can assist pathologists in detecting and classifying gastric poorly differentiated adenocarcinoma from ESD WSIs would be of great benefit for routine histopathological diagnostic workflow. Methods: In this study, we trained the deep learning model to classify poorly differentiated adenocarcinoma in ESD WSIs by transfer and weakly supervised learning approaches. Results: We evaluated the model on ESD, endoscopic biopsy, and surgical specimen WSI test sets, achieving and ROC-AUC up to 0.975 in gastric ESD test sets for poorly differentiated adenocarcinoma. Conclusion: The deep learning model developed in this study demonstrates the high promising potential of deployment in a routine practical gastric ESD histopathological diagnostic workflow as a computer-aided diagnosis system.

External validation of the BEST-J score and a new risk prediction model for ESD delayed bleeding in patients with early gastric cancer

Background

Delayed bleeding is an important adverse event after gastric endoscopic submucosal dissection (ESD). We aimed to externally validate the Bleeding after ESD Trend from Japan (BEST-J) score and subsequently develop a risk prediction model for bleeding in Chinese patients with early gastric cancer (EGC) after ESD.

Methods

The clinical data of patients who underwent ESD for EGC in Beijing Friendship Hospital from June 2013 to December 2019 were collected retrospectively. The BEST-J score was evaluated according to the clinical data. Through univariate and multivariate logistic regression analyses of the clinical data, the factors affecting delayed bleeding were identified, and a new risk prediction model for bleeding was established. Receiver operating characteristic (ROC) curves were used to evaluate the predictive value of the two prediction models.

Results

A total of 444 patients with EGC undergoing ESD were included, of whom 27 patients had delayed bleeding (6.1%). Multivariate logistic regression analysis showed that a history of smoking (P = 0.029), tumor size > 20 mm (P = 0.022), intraoperative use of hemoclips (P = 0.025), resection of multiple tumors (P = 0.027), and prolongation of activated partial thromboplastin time (APTT) (P = 0.020) were independent influencing factors for delayed bleeding. ROC curve analysis showed that the areas under the curves (AUCs) were different between the BEST-J score and the newly built prediction model (0.624 vs. 0.749, P = 0.012).

Conclusions

The BEST-J score has moderately good discrimination for Chinese patients with EGC. However, for patients with EGC without severe comorbidities, the new risk prediction model may predict delayed bleeding better than the BEST-J score.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-022-02273-2.

Recent approach for preventing complications in upper gastrointestinal endoscopic submucosal dissection

Although endoscopic submucosal dissection (ESD) is a minimally invasive treatment method for upper gastrointestinal (GI) tumors, patients undergoing upper GI ESD sometimes fall into a serious condition from complications. Thus, it is important to fully understand how to prevent complications when performing upper GI ESD. One of the major complications in esophageal and gastric ESD is intraoperative perforation. To prevent this complication, blind dissection should be avoided. Traction-assisted ESD is a useful technique for maintaining good endoscopic view. This method was proven to reduce the incidence of intraoperative perforation, which would become a standard technique in esophageal and gastric ESD. In gastric ESD, delayed bleeding is the most common complication. Recently, a novel prediction model (BEST-J score) consisting of 10 factors with four risk categories for delayed bleeding in gastric ESD was established, and a free mobile application is now available. For reducing delayed bleeding in gastric ESD, vonoprazan ≥20 mg/day is the sole reliable method in the current status. Duodenal ESD is still challenging with a much higher frequency of complications, such as perforation and delayed bleeding, than ESD in other organs. However, with the development of improved devices and techniques, the frequency of complications in duodenal ESD has been decreasing. To prevent intraoperative perforation, some ESD techniques, such as using the distal tips of the Clutch Cutter, were developed. An endoscopic mucosal defect closure technique would be mandatory for preventing delayed complications. However, several unresolved issues, including standardization of duodenal ESD, remain and further studies are demanded.

A review on recent advancements in diagnosis and classification of cancers using artificial intelligence

Artificial intelligence has illustrated drastic changes in radiology and medical imaging techniques which in turn led to tremendous changes in screening patterns. In particular, advancements in these techniques led to the development of computer aided detection (CAD) strategy. These approaches provided highly accurate diagnostic reports which served as a "second-opinion" to the radiologists. However, with significant advancements in artificial intelligence strategy, the diagnostic and classifying capabilities of CAD system are meeting the levels of radiologists and clinicians. Thus, it shifts the CAD system from second opinion approach to a high utility tool. This article reviews the strategies and algorithms developed using artificial intelligence for the foremost cancer diagnosis and classification which overcomes the challenges in the traditional method. In addition, the possible direction of AI in medical aspects is also discussed in this study.

Circulating serum exosomal miR-92a-3p as a novel biomarker for early diagnosis of gastric cancer

Gastric cancer (GC) is one of the common malignant tumors with high mortality. The abundance of miRNAs in serum exosomes has proved to have a high application value as a new noninvasive diagnostic method. The purpose of this study was to investigate whether serum exosomal miR-92a-3p could be used as a new biomarker for early diagnosis of GC and evaluate its clinical application value by detecting the expression of serum exosomal miR-92a-3p in 131 patients with primary GC and 122 healthy controls by real-time quantitative (qRT)-PCR. The results showed that the expression level of serum exosomal miR-92a-3p in GC patients was significantly lower than that in normal controls (p < 0.0001). In addition, the level was closely correlated with lymph node metastasis and tumor node metastasis stage of GC patients. The area under the curve for serum exosomal miR-92a-3p was 0.829, significantly higher than for other indicators. Furthermore, combined detection of serum exosomal miR-92a-3p, CEA and CA19-9 was more sensitive than any of the three alone or any pair. These results showed that serum exosomal miR-92a-3p could be used as a novel new tumor biomarker to improve diagnostic efficiency in GC.

Comparison of Endoscopic Submucosal Dissection Application on Mucosal Tumor and Subepithelial Tumor in stomach

Background: Endoscopic submucosal dissection is minimal invasive endoscopic procedure to deal with gastric tumor. Initially, it was developed to resect mucosal neoplasm since 2000 and extended its application to submucosal tumor in the following years. Although the basic ESD skills are similar in gastric mucosal tumor and subepithelial tumor, the success rate, complication may be different between the two types of gastric tumor resection. This retrospective study is conducted to analyze the ESD procedure in gastric mucosal tumor and subepithelial tumor.

Methods: From 2007 to 2016, we reviewed all patients who underwent endoscopic submucosal dissection for gastric mucosal tumor and subepithelial tumor in Kaohsiung Medical University Hospital.

Results: Totally, 35 patients with gastric subepithelial tumor and 41 patients with gastric mucosal tumor received endoscopic submucosal dissection are enrolled. Among 35 patients with subepithelial tumor, 32 (91.4%) patients achieved curative treatment. 1 patient received emergent operation and 2 patients received salvage operation to complete tumor resection. 8 patients (22.9%) occurred perforation and no delay bleeding was found. Among 41 patients with mucosal neoplasm, 30 (71.4%) patients achieved curative treatment. 2 patients received emergent operation and 9 patients received salvage operation to complete tumor resection. 9 patients (21.9%) occurred complication, 6 patients occurred delay bleeding and 3 patients had perforation.

Conclusions: Comparing ESD between gastric mucosal tumor and subepithelial tumor, ESD had similar efficiency in curative treatment. However, ESD in subepethelial tumor encountered higher perforation and lesser delay bleeding.

Life on a knife edge: the optimal approach to the management of perforations during endoscopic submucosal dissection (ESD)

INTRODUCTION

Endoscopic submucosal dissection (ESD) is a well-established procedure that can provide curative resection of malignant and premalignant lesions endoscopically, thereby offering patients an effective non-operative option. Though ESD is safe and highly effective when performed in appropriately selected patients by an experienced ESD expert, it carries risks including intraprocedural and delayed perforation.

AREAS COVERED

This review provides a practical approach to the initial management of perforation to minimize subsequent complications. The importance of prompt recognition of perforation and early intervention cannot be overstated. This review summarizes indications for closure, anatomic considerations impacting closure, and closure techniques. This article also highlights the do's and don'ts of various closure devices, focusing particularly on advanced closure methods, the-over-the-scope clips (OTSCs) and endoscopic suturing.

EXPERT OPINION

As ESD offers surgery-sparing alternatives to patients, advanced closure techniques allow endoscopists to effectively and promptly manage associated complications, improving the possibility of the widespread implementation of ESD in the US. With continued improvements in OTSCs and endoscopic suturing, ESD will become a stalwart of endoscopic management of malignant and premalignant gastrointestinal lesions.

Kyoto classification in patients who developed multiple gastric carcinomas after Helicobacter pylori eradication

BACKGROUND

Endoscopic Kyoto classification predicts gastric cancer risk; however, the score in the patients with primary gastric cancer after Helicobacter pylori (H. pylori) eradication therapy is unknown.

AIM

To elucidate the Kyoto classification score in patients with both single gastric cancer and multiple gastric cancers developed after H. pylori eradication.

METHODS

The endoscopist recorded the Kyoto classification at the endoscope and the Kyoto classification score at the time of the first diagnosis of gastric cancer after H. pylori eradication. The score was compared between single gastric cancer group and multiple gastric cancers group.

RESULTS

The Kyoto score at the time of diagnosis of 45 cases of gastric cancer after H. pylori eradication was 4.0 points in average. The score was 3.8 points in the single gastric cancer group, and 5.1 points in the multiple gastric cancers group. The multiple group had a significantly higher score than the single group (P = 0.016). In the multiple gastric cancers group, all the patients (7/7) had 5 or higher Kyoto score, while in single gastric cancer group, the proportion of patients with a score of 5 or higher was less than half, or 44.7% (17/38).

CONCLUSION

Patients diagnosed with gastric cancer after H. pylori eradication tended to have advanced gastritis. In particular, in cases of multiple gastric cancers developed after H. pylori eradication, the endoscopic Kyoto classification score tended to be 5 or higher in patients with an open type atrophic gastritis and the intestinal metaplasia extended to the corpus.

Efficacy of a new image-enhancement technique for achieving hemostasis in endoscopic submucosal dissection

BACKGROUND AND AIMS

Hemostasis during endoscopic submucosal dissection (ESD) can sometimes be challenging and stressful for the endoscopist. Therefore, we aimed to assess the usefulness of dual red imaging (DRI), a new image enhancement technique that uses 3 wavelengths (540, 600, and 630 nm) to visualize bleeding points and to examine the efficacy of DRI in shortening the time required to achieve hemostasis (hemostasis time) during ESD.

METHODS

DRI and white-light imaging (WLI) were used alternately for managing 378 bleeding events in 97 patients undergoing ESD. Hemostasis time for each hemostasis event was measured. Using portable eye-tracking glasses, 4 experienced endoscopists were shown random videos of intraoperative bleeding during ESD (20 cases each on WLI and DRI) and identified the bleeding point in each video. The mean distances of eye movement per unit of time until the bleeding point were identified in each video and compared between the WLI and DRI groups.

RESULTS

Average hemostasis time was significantly shorter in the DRI group. The mean distance of eye movement was significantly shorter in the DRI group than in the WLI group for all endoscopists.

CONCLUSIONS

DRI can offer useful images to help in clearly detecting bleeding points and in facilitating hemostasis during ESD. It is feasible and may help in successfully performing ESD that is safer and faster than WLI. (Clinical trial registration number: UMIN000018309.).

A Recent Argument for the Use of Endoscopic Submucosal Dissection for Early Gastric Cancers

Endoscopic submucosal dissection (ESD) has become the standard treatment method for early gastric cancers (EGCs) due to the negligible risk for lymph node metastasis (LNM) in Eastern Asian countries. According to the guidelines, the curability of EGC after endoscopic resection was classified into three groups: curative resection, expanded curative resection, and noncurative resection. In Eastern Asian countries, a structured follow-up schedule is needed for patients undergoing curative resection and expanded curative resection. Conversely, in Western countries, additional surgery may be recommended for some patients undergoing expanded curative resection (ulcerated, undifferentiated, or slight submucosal invasion) due to the potential risk for LNM, even though specimens of ESD and surgery may not be handled with the same methodology as that used in Japan, which may lead to this slightly higher risk. In noncurative resection, additional surgery is the standard method after ESD because of the risk for LNM. However, in elderly patients and/or those with severe underlying diseases, the advantages and disadvantages of additional surgery should be considered when selecting a post-ESD treatment strategy for patients undergoing noncurative resection. Risk-scoring systems for LNM may facilitate clinical decisions for these patients. However, it should be noted that when recurrence was detected in patients who were followed up with no additional treatment after ESD with noncurative resection, most of them had a poor prognosis. To select an appropriate treatment method, especially in elderly patients undergoing ESD with noncurative resection, a new tool for evaluating the condition of patients should be established.

Comparison of subjective quality of life after endoscopic submucosal resection or surgery for early gastric cancer

Quality of life (QoL) has become an important issue after early gastric cancer (EGC) treatment. We aimed to compare the QoL of EGC survivors after ESD (n = 241) or laparoscopic subtotal gastrectomy (n = 241) without recurrence and to evaluate the QoL over the 5-year period after adjusting for various confounding factors related to QoL. QoL related to the gastric cancer subscale (GCS) was significantly higher in the ESD group than surgery group (p < 0.001). After adjusting for all possible confounding factors, survivors who underwent ESD still had higher QoL related to CSG than those who underwent surgery. On the analysis of interaction effects for all QoL subscales, higher QoL related to GCS of ESD group than those of surgery group has been kept over time (p = 0.983). Therefore, we concluded that EGC survivors who undergo ESD have significantly better QoL related to GCS over a 5-year period after treatment than those who undergo surgery. This may be a useful consideration when selecting treatment modalities for patients with EGC.

Long-term follow-up of endoscopic submucosal dissection of gastric dysplasia and early neoplasia in a United Kingdom Caucasian population - a tertiary centre experience

Introduction: Endoscopic submucosal dissection (ESD) is extensively performed for the treatment of early gastric cancer (EGC) in the Eastern countries due to its favourable outcomes compared to gastrectomy in terms of lower complication rates, shorter hospital stays, better quality of life, with similar 5-year survival rate. Yet, its use is still limited in the UK.Aim: A long-term follow-up study to evaluate the outcome of ESD in the treatment of EGC in a Caucasian population at a tertiary referral centre in the United Kingdom.Methods: Data for the 35 Caucasian patients, who underwent ESD in a tertiary referral centre between May 2012 and June 2017 were collected. The selected patients were followed-up until May 2018. Curative resection (CR) and survival rates were used to measure the efficacy of ESD.Results: ESD was attempted on 46 lesions and completed on 37. En-bloc and CR rates of 57% and 19% were achieved, respectively. 24% of the lesions were non-CR and 57% were indefinite for non-CR/CR and 41% of the lesions showed change in histological grade post-ESD. Complete reversal of dysplasia/neoplasia was seen in 60% of the 'indefinite' group and 100% of the CR group at latest FU (18 months, mean). Recurrence was seen in 23% of the patients at latest FU. Seventy-one months' survival rate was 77%, while the disease-specific mortality was 0%.Conclusions: This study demonstrates the positive long-term outcome of ESD for gastric neoplasia in a UK Caucasian population, encouraging further development and implementation of ESD in the UK.

History and future perspectives in Japanese guidelines for endoscopic resection of early gastric cancer

Japanese guidelines for gastric cancer treatment were first published in 2001 for the purpose of showing the appropriate indication for each treatment method, thereby reducing differences in the therapeutic approach among institutions, and so on. With the accumulation of evidence and the development and prevalence of endoscopic submucosal dissection (ESD), the criteria for the indication and curability of endoscopic resection (ER) for early gastric cancer (EGC) have expanded. However, several problems still remain. Although a risk-scoring system (eCura system) for predicting lymph node metastasis (LNM) may help treatment decision in patients who do not meet the curative criteria for ER of EGC, which is referred to as eCura C-2 in the latest guidelines, additional gastrectomy with lymphadenectomy may be excessive for many patients, even those at high risk for LNM. Less-invasive function-preserving surgery, such as non-exposed endoscopic wall-inversion surgery with laparoscopic sentinel node sampling, may overcome this problem. In addition, further less-invasive treatment, such as ER with chemotherapy, should be established for patients who prefer not to undergo additional gastrectomy.

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.

Current controversies in treating remnant gastric cancer: Are minimally invasive approaches feasible?

The incidence of remnant gastric cancer (RGC) is still increasing. Minimally invasive approaches including endoscopic resection, laparoscopic and robotic approaches, and function-preserving gastrectomy have been utilized as curative treatment methods for primary gastric cancer. However, adhesions and anatomical alterations due to previous gastrectomy make the use of minimally invasive approaches complicated and difficult for RGC. Application of these approaches for the treatment of RGC is still controversial. Endoscopic submucosal dissection is a favorable alternative therapy for the resection of early gastric cancer that occurs in the remnant stomach and can prevent unnecessary complications. The majority of retrospective studies have shown that endoscopic submucosal dissection is an effective and oncologically safe treatment modality for RGC. Subtotal gastrectomy could serve as a function-preserving gastrectomy for patients with early RGC and improve postoperative late-phase function. However, there are only two studies that demonstrate the feasibility and oncological efficacy of subtotal gastrectomy for RGC. The non-randomized controlled trials showed that compared to open gastrectomy, laparoscopic gastrectomy for RGC led to better short-term outcomes and similar oncologic results. Because of the rarity of RGC, future multicenter studies are required to determine the indications of minimally invasive treatment for RGC.

Multimodality management of locally advanced gastric cancer-the timing and extent of surgery

The optimal treatment for patients with locally advanced gastric adenocarcinoma is multimodal. Surgery is the cornerstone of therapeutic strategies with curative intent. The addition of chemotherapy or chemoradiation decreases rate of recurrence and prolongs survival. Guidelines differ between countries and there is no universal standard of care. Modern studies of patients with locally advanced gastric cancer showed that adjuvant chemotherapy improves survival over surgery alone in Asia. These studies could not be replicated in Europe. Peri-operative chemotherapy strategies, conversely, have been effective in Europe for improving overall and disease free survival. Adjuvant chemoradiation has also demonstrated improved survival when compared to surgery alone, but studies comparing chemotherapy with chemoradiation have not shown significant difference. Trials are ongoing to examine the role of chemoradiation in a neoadjuvant fashion. A D2 extent of lymphadenectomy improves cancer related survival for those who do not undergo distal pancreatectomy/splenectomy. Survival is also associated not only with the extent but also the number of lymph nodes examined. There are ongoing trials related to immunotherapy and targeted therapies, which may also impact or change the treatment paradigm for locally advanced gastric cancer.

Haemostasis treatment using dual red imaging during endoscopic submucosal dissection: a multicentre, open-label, randomised controlled trial

INTRODUCTION

Patients scheduled to undergo oesophageal, gastric and colorectal endoscopic submucosal dissection (ESD) are to be investigated to verify the efficacy of dual red imaging (DRI) for establishing haemostasis during ESD.

METHODS AND ANALYSIS

The trial is designed as a multicentre, open-label randomised, parallel-group, controlled intervention study. Registered patients will be randomly assigned to DRI and white light imaging (WLI) groups. In the DRI group, the mucosal incision and submucosal dissection will be performed by WLI, and haemostasis will be managed by DRI when bleeding occurs. In the WLI group, the mucosal incision and submucosal dissection are to be performed by WLI and the haemostasis management is to be performed by WLI. The primary endpoint is the time from the recognition of bleeding up to the achievement of complete haemostasis (haemostasis time). The secondary endpoints are the operation time, the proportion of cases in which perforation occurs, and the psychological stress experienced by the endoscopist during haemostasis treatment.

ETHICS AND DISSEMINATION

This trial was approved by the Keio University Review Board for Clinical Trials (5 December 2016).

DISCUSSION

This will be the first multicentre collaborative research using DRI for haemostasis treatment during ESD. When the safety and simplicity of DRI as a treatment for haemostasis during ESD can be proven, the ESD procedure can be simplified and disseminated more widely in clinical practice.

TRIAL REGISTRATION NUMBER

UMIN000025134.

Initial and crucial genetic events in intestinal-type gastric intramucosal neoplasia

Gastric cancer (GC) is one of the most common and life-threatening malignancies. The course of disease and tumor aggressiveness vary among GCs, although how early fate is determined and by what factors remains elusive. To solve this question, we collected 43 gastric intramucosal neoplasias (GINs), comprising dysplasia/intraepithelial neoplasia (D/IEN; a premalignant lesion) and minute GC (miGC; ≤10 mm) of intestinal histotype and performed targeted deep DNA sequencing of 67 GC-related genes derived from large-scale data. Gastric D/IEN was classified into low or high grade (LG-D/IEN or HG-D/IEN). The most frequent mutations in D/IENs included APC (19/25; 76%), ARID2 (6/25; 24%) and MUC6 (5/25; 20%). All LG-D/IENs had APC mutation (12/12) and APC hotspot mutations affecting R1450 and E1554 were noted in both LG-D/IEN and HG-D/IEN. ARID2 mutation always co-occurred with APC mutation, whose tumor variant allele frequency (TVAF) was higher than that of ARID2 in D/IEN. APC and TP53 mutations were mutually exclusive in D/IEN (p = 0.031 [main cohort], p = 0.025 [expanding cohort]) and TP53-mutated D/IEN was exclusively HG-D/IEN (4/4). TP53 mutations were highly recurrent (11/14; 79%) in MLH1-positive miGCs and were detected even in two microscopic lesions measuring 1 and 3 mm, respectively. Furthermore, TVAF analyses suggested that TP53 mutation is the initial event in the TP53-mutated miGCs. In contrast, TP53 mutation was absent (0/4) in MLH1-negative small intramucosal carcinoma (8-24 mm). Advanced GC data suggested that early mutations (APC and TP53) may affect the potential of cancerous progression from D/IEN. This study revealed somatic mutational landscape and initial mutations of GINs, and we report for the first time that TP53 mutations precede other mutations in intestinal-type GC. Our results also indicate that molecular subtyping based on APC/TP53 mutations would be a high-priority approach for determining and predicting the malignant potential of GIN, including D/IEN. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Novel surgical approach based on the sentinel node concept in patients with early gastric cancer

Recent prospective multicenter trials have demonstrated the clinical safety and efficacy of sentinel node navigation surgery (SNNS) in patients with early gastric cancer. Further, development of an intraoperative imaging system and an indocyanine green fluorescence imaging approach has been attracting attention as a novel tool for detection of the sentinel node (SN). The greatest advantage of an in vivo imaging system is that it visualizes SN and afferent lymphatic vessels from the primary tumor site more clearly than the conventional dye approach. Besides visualization of the SN, it is also essential to accurately assess the presence or absence of lymph node metastasis in the intraoperative management of SNNS. However, the clinical significance of lymph node micrometastasis (LNM) in patients with gastric cancer remains controversial. Reverse transcription‐polymerase chain reaction (RT‐PCR) is one of the representative assays used to identify LNM. A rapid RT‐PCR assay that completes the detection of LNM within approximately 40 minutes has recently been produced and applied in the clinical management of SNNS. From the viewpoint of surgical methods, modified laparoscopic and endoscopic cooperative surgery with non‐exposed approaches has recently been highlighted as a promising technique to prevent tumor dissemination caused by surgical procedures, and is likely to be clinically applied to SNNS in the future. When carrying out SNNS as a minimally invasive surgery, it is important to consider the balance between post‐surgical quality of life and curability. Future prospective studies on SNNS will greatly contribute to furthering its establishment as a beneficial procedure for patients with early gastric cancer.