Magnifying endoscopy simple diagnostic algorithm for early gastric cancer (MESDA-G)

British Society of Gastroenterology guidelines on the diagnosis and management of patients at risk of gastric adenocarcinoma

Gastric adenocarcinoma carries a poor prognosis, in part due to the late stage of diagnosis. Risk factors include Helicobacter pylori infection, family history of gastric cancer-in particular, hereditary diffuse gastric cancer and pernicious anaemia. The stages in the progression to cancer include chronic gastritis, gastric atrophy (GA), gastric intestinal metaplasia (GIM) and dysplasia. The key to early detection of cancer and improved survival is to non-invasively identify those at risk before endoscopy. However, although biomarkers may help in the detection of patients with chronic atrophic gastritis, there is insufficient evidence to support their use for population screening. High-quality endoscopy with full mucosal visualisation is an important part of improving early detection. Image-enhanced endoscopy combined with biopsy sampling for histopathology is the best approach to detect and accurately risk-stratify GA and GIM. Biopsies following the Sydney protocol from the antrum, incisura, lesser and greater curvature allow both diagnostic confirmation and risk stratification for progression to cancer. Ideally biopsies should be directed to areas of GA or GIM visualised by high-quality endoscopy. There is insufficient evidence to support screening in a low-risk population (undergoing routine diagnostic oesophagogastroduodenoscopy) such as the UK, but endoscopic surveillance every 3 years should be offered to patients with extensive GA or GIM. Endoscopic mucosal resection or endoscopic submucosal dissection of visible gastric dysplasia and early cancer has been shown to be efficacious with a high success rate and low rate of recurrence, providing that specific quality criteria are met.

Epstein-Barr virus status is a promising biomarker for endoscopic resection in early gastric cancer: proposal of a novel therapeutic strategy

BACKGROUND

Epstein-Barr virus-positive gastric cancer (EBVGC) is associated with a low prevalence of lymph node metastasis (LNM); however, EBV status is not considered in the indication of endoscopic resection (ER). We aimed to clarify the implication of EBV status for ER of pT1b GC.

METHODS

Consecutive cases of pT1b GCs treated with surgery between 2005 and 2014 were retrospectively analyzed. Clinicopathological factors and LNM status were compared between EBVGC and non-EBVGC groups.

RESULTS

EBVGC accounted for 7.9% (71 of 898) cases. Compared to non-EBVGC, EBVGC was more frequent in males (p = 0.0055), the upper third region (p < 0.0001), showed elevated growth features (p = 0.0059), and was associated with a lower frequency of accompanying ulceration (p = 0.002), greater depth of submucosal invasion (p = 0.017), and lower frequency of lymphatic invasion (p < 0.0001). Frequency of LNM was significantly lower in EBVGC than in non-EBVGC (4.2% vs. 21.9%, p < 0.0001). In EBVGC, tumors without lymphovascular invasion showed significantly lower frequency of LNM than those with lymphovascular invasion (0 of 50, 0%; vs 3 of 21, 14.3%; p = 0.023). Histologically, 84.5% (60 of 71) of EBVGC included carcinomas with lymphoid stroma and/or lace pattern components.

CONCLUSIONS

pT1b EBVGC is a convincing candidate for ER, regardless of risk factors other than lymphovascular invasion.

Endoscopic gastric mucosal atrophy as a predictor of colorectal polyps: a large scale case-control study

Although some studies have indicated a correlation between Helicobacter pylori infection and the risk of colorectal neoplasms, these findings have not been consistent and are controversial. This case-control study aimed to investigate the association between endoscopic gastric mucosal atrophy and colorectal polyp occurrence. Records of 7,394 participants who underwent colonoscopy examinations from August 2008 to July 2018 were reviewed retrospectively. A total of 2,404 subjects were registered; 1,565 (65.1%) were in the gastric mucosal atrophy-positive group and 1,138 (47.3%) had colorectal polyps. The multivariate analysis adjusted by age, sex, smoking habits, alcohol habits, hemoglobin A1c, and systolic blood pressure indicated that patients in the gastric mucosal atrophy-positive group more frequently had colorectal polyps compared with patients in the gastric mucosal atrophy-negative group (odds ratio, 3.27; 95% confidence interval, 2.68-4.01; p<0.001). An analysis of the association between gastric mucosal atrophy degree and colorectal polyp status indicated that, compared with mild gastric mucosal atrophy, severe gastric mucosal atrophy was associated with a higher risk of proximal colon polyps (odds ratio, 1.47; 95% confidence interval, 1.05-2.07; p = 0.024) and two or more colorectal polyps (odds ratio, 1.80; 95% confidence interval, 1.30-2.49; p<0.001). In conclusion, gastric mucosal atrophy found during esophagogastroduodenoscopy may be an indication for complete colon screening.

Modified laser-based photodynamic endoscopic diagnosis for early gastric cancer

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Influence of Helicobacter pylori Infection on Endoscopic Findings of Gastric Adenocarcinoma of the Fundic Gland Type

PURPOSE

Gastric adenocarcinoma of the fundic gland type (chief cell predominant type) (GA-FG-CCP) was first reported as a rare adenocarcinoma found in the normal fundic mucosa. Recent studies have proposed the possibility that GA-FG-CCPs were also generated in the atrophic mucosa after Helicobacter pylori (HP) eradication therapy. However, little is known on the endoscopic findings of GA-FG-CCP generated in the atrophic mucosa due to its extreme rarity.

MATERIALS AND METHODS

A total of 8 patients who underwent endoscopic submucosal resection and were diagnosed with GA-FG-CCP generated in the HP-uninfected mucosa (4 cases, HP-uninfected group) or HP-eradicated atrophic mucosa (4 cases, HP-eradicated group) were retrospectively analyzed, and their endoscopic findings, including magnifying endoscopy with narrow band imaging (M-NBI), and pathological features were compared.

RESULTS

While GA-FG-CCPs in the 2 groups displayed similar macroscopic appearance, M-NBI demonstrated that characteristic microvessels (tapered microvessels like withered branches) were specifically identified in the HP-eradicated group. Pathological investigation revealed that a decreasing number of fundic glands and thinned foveolar epithelium covering tumor ducts were thought to lower the thickness of the covering layer over tumor ducts in the HP-eradicated group. Moreover, dilation of vessels just under the surface of the lesions contributed to the visualization of microvessels by M-NBI.

CONCLUSIONS

The change in background mucosa due to HP infection influenced the thickness of the covering layer over the tumor ducts and M-NBI finding of GA-FG-CCP.

Diagnosis of early gastric cancer based on fluorescence hyperspectral imaging technology combined with partial-least-square discriminant analysis and support vector machine

This study investigated the feasibility of using fluorescence hyperspectral imaging technology to diagnose of early-stage gastric cancer. Fluorescence spectral images of 76 patients who were pathologically diagnosed as non-atrophic gastritis, premalignant lesions and gastric cancer were collected. Fluorescence spectra at 100-pixel points were randomly extracted after binarization. Diagnostic models of non-atrophic gastritis, premalignant lesions and gastric cancer were constructed through partial-least-square discriminant analysis (PLS-DA) and support vector machine (SVM) algorithms. The prediction effects of PLS-DA and SVM models were compared. Results showed that the average spectra of normal, precancerous and gastric cancer tissues significantly differed at 496, 546, 640 and 670 nm, and regular changes in fluorescence intensity at 546 nm were in the following order: normal > precancerous lesions > gastric cancer. Additionally, the effect of the diagnostic model established by SVM is significantly better than PLS-DA which accuracy, specificity and sensitivity are above 94%. Experimental results revealed that the fast diagnostic model of early gastric cancer by combining fluorescence hyperspectral imaging technology and improved SVM was effective and feasible, thereby providing an accurate and rapid method for diagnosing early-stage gastric cancer.

Advanced endoscopic methods in gastrointestinal diseases: a systematic review

Endoscopic imaging is the main method for detecting gastrointestinal diseases, which adversely affect human health. White light endoscopy (WLE) was the first method used for endoscopic examination and is still the preliminary step in the detection of gastrointestinal diseases during clinical examination. However, it cannot accurately diagnose gastrointestinal diseases owing to its poor correlation with histopathological diagnosis. In recent years, many advanced endoscopic methods have emerged to improve the detection accuracy by endoscopy. Chromoendoscopy (CE) enhances the contrast between normal and diseased tissues using biocompatible dye agents. Narrow band imaging (NBI) can improve the contrast between capillaries and submucosal vessels by changing the light source acting on the tissue using special filters to realize the visualization of the vascular structure. Flexible spectral imaging color enhancement (FICE) technique uses the reflectance spectrum estimation technique to obtain individual spectral images and reconstructs an enhanced image of the mucosal surface using three selected spectral images. The i-Scan technology takes advantage of the different reflective properties of normal and diseased tissues to obtain images, and enhances image contrast through post-processing algorithms. These abovementioned methods can be used to detect gastrointestinal diseases by observing the macroscopic structure of the digestive tract mucosa, but the ability of early cancer detection is limited with low resolution. However, based on the principle of confocal imaging, probe-based confocal laser endomicroscopy (pCLE) can enable cellular visualization with high-performance probes, which can present cellular morphology that is highly consistent with that shown by biopsy to provide the possibility of early detection of cancer. Other endoscopic imaging techniques including endoscopic optical coherence tomography (EOCT) and photoacoustic endoscopy (PAE), are also promising for diagnosing gastrointestinal diseases. This review focuses on these technologies and aims to provide an overview of different technologies and their clinical applicability.

Contemporary paradigm for the evaluation and treatment of hereditary gastric cancer

Gastric cancer is the third leading cause of cancer mortality worldwide. Survival is linked to stage at diagnosis and tolerance to surgery and adjuvant therapy. The emergence of sophisticated methods to identify patients at high risk for the development of gastric cancer has given us an opportunity to eliminate a lethal disease in an identifiable patient population. Guidelines and recommendations have been established and prophylactic total gastrectomy is considered the most effective treatment. However, this requires substantial physical and emotional investment. It is imperative that patients and families are supported by genetic counseling, ongoing surveillance, and survivorship studies.

An Asian consensus on standards of diagnostic upper endoscopy for neoplasia

BACKGROUND

This is a consensus developed by a group of expert endoscopists aiming to standardise the preparation, process and endoscopic procedural steps for diagnosis of early upper gastrointestinal (GI) cancers.

METHOD

The Delphi method was used to develop consensus statements through identification of clinical questions on diagnostic endoscopy. Three consensus meetings were conducted to consolidate the statements and voting. We conducted a systematic literature search on evidence for each statement. The statements were presented in the second consensus meeting and revised according to comments. The final voting was conducted at the third consensus meeting on the level of evidence and agreement.

RESULTS

Risk stratification should be conducted before endoscopy and high risk endoscopic findings should raise an index of suspicion. The presence of premalignant mucosal changes should be documented and use of sedation is recommended to enhance detection of superficial upper GI neoplasms. The use of antispasmodics and mucolytics enhanced visualisation of the upper GI tract, and systematic endoscopic mapping should be conducted to improve detection. Sufficient examination time and structured training on diagnosis improves detection. Image enhanced endoscopy in addition to white light imaging improves detection of superficial upper GI cancer. Magnifying endoscopy with narrow-band imaging is recommended for characterisation of upper GI superficial neoplasms. Endoscopic characterisation can avoid unnecessary biopsy.

CONCLUSION

This consensus provides guidance for the performance of endoscopic diagnosis and characterisation for early gastric and oesophageal neoplasia based on the evidence. This will enhance the quality of endoscopic diagnosis and improve detection of early upper GI cancers.

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

BACKGROUND/AIMS

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

METHODS

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

RESULTS

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

CONCLUSION

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

Magnified endoscopy with narrow-band imaging for the differential diagnosis of superficial non-ampullary duodenal epithelial tumors

BACKGROUND AND AIM

Differentiation of low-grade adenoma (Vienna category 3, C3) and high-grade adenoma/carcinoma (C4/5) among superficial non-ampullary duodenal epithelial tumors (SNADETs) using magnified endoscopy with narrow-band imaging (MNBI) is not established. The aim of this study is to clarify the diagnostic ability of MNBI to differentiate between C3 and C4/5 among SNADETs.

METHODS

A total of 585 MNBI images taken from 156 SNADETs were evaluated in a test and validation phase. In the test phase, MNBI patterns were extracted based on the combination of surface structure and vasculature. Comparison between MNBI patterns and histology was performed to establish diagnostic criteria to differentiate between C3 and C4/5. In the validation phase, the accuracy and interobserver agreement of the diagnostic criteria were assessed.

RESULTS

Four MNBI patterns (network, disappeared, white opaque substance and intrastructural vessels) with distinctive histological features were selected. The median number of MNBI patterns observed among C3 and C4/5 differed with significance (1 vs 2, p < .01). The pattern of disappeared was suggestive of C4/5. Diagnosis of C4/5 by using the criteria of 2 or more MNBI patterns or presence of disappeared pattern revealed a sensitivity of 76%, specificity of 63% and accuracy of 72%. Interobserver agreement of recognizing MNBI patterns was moderate (kappa 0.59).

CONCLUSION

Diagnosis based on MNBI patterns is useful to differentiate between C3 and C4/5 lesions among SNADETs.

Endoscopic and clinicopathological features of intramucosal, histologically mixed-type, low-grade, well-differentiated gastric tubular adenocarcinoma with the potential for late-onset lymph node metastasis

BACKGROUND

Intramucosal, histologically mixed-type, low-grade (LG), well-differentiated gastric tubular adenocarcinomas (tub1s; LG-tub1s) have larger mean diameters and exhibit a higher frequency of the gastric mucin phenotype (G-phenotype) than pure LG-tub1s. In proportion to their increases in diameter, G-phenotype differentiated-type early gastric cancer (EGC) tumours reportedly grow to eventually contain (an) undifferentiated-type component(s) and LG-tub1s, which are included in differentiated-type EGCs, reportedly exhibit changes in their glandular architectural and cytological atypia grades from LG to high-grade (HG) and can grow to contain a moderately differentiated tubular adenocarcinoma (tub2) component and undifferentiated components. Because they generally show a higher frequency of malignancy relative to tumours with a higher atypia grade and lower differentiation degree, it is suggested that, among mixed-type LG-tub1s, G-phenotype LG-tub1s containing an HG-tub2 component (LG-tub1s > HG-tub2) with undifferentiated components might lead to late-onset metastasis to lymph nodes even after a successful endoscopic submucosal dissection (ESD). We aimed to clarify the endoscopic and clinicopathological features of these G-phenotype LG-tub1s > HG-tub2.

METHODS

Of the 13,217 oesophagogastroduodenoscopies performed at our institutions between September 2008 and March 2016, 185 EGC lesions were evaluated in this retrospective observational study. Among these EGC lesions, 60 intramucosal LG-tub1s were divided into 53 tub1 (44 pure LG-tub1s and nine LG-tub1s containing HG-tub1) lesions and seven LG-tub1 > tub2 (LG-tub1 containing LG- and HG-tub2) lesions.

RESULTS

The frequencies of the superficial depressed type (P = 0.026), reddish colour (P = 0.006), HG of contained tub2s (P = 0.006), and G-phenotype (P = 0.028) were significantly higher in the LG-tub1 > tub2 group than those in the tub1 group. However, the largest lesion of the LG-tub1 > tub2 group had a superficial flat appearance, an isochromatic colour, an HG-tub2 and an undifferentiated component, and a large diameter greater than 30 mm, and it exhibited a G-phenotype.

CONCLUSIONS

Intramucosal G-phenotype LG-tub1s > HG-tub2 are potential premalignant stomach neoplasms that may have specific endoscopic and clinicopathological features. However, G-phenotype LG-tub1s > HG-tub2 with undifferentiated component, which potentially show higher malignancy than those without undifferentiated components might change from a reddish to isochromatic colour. Accurately diagnosing, treating, and following-up G-phenotype LG-tub1s > HG-tub2 might decrease the number of patients who experience late-onset metastasis after ESD.

Narrow-Band Imaging: Clinical Application in Gastrointestinal Endoscopy

Narrow-band imaging is an advanced imaging system that applies optic digital methods to enhance endoscopic images and improves visualization of the mucosal surface architecture and microvascular pattern. Narrow-band imaging use has been suggested to be an important adjunctive tool to white-light endoscopy to improve the detection of lesions in the digestive tract. Importantly, it also allows the distinction between benign and malignant lesions, targeting biopsies, prediction of the risk of invasive cancer, delimitation of resection margins, and identification of residual neoplasia in a scar. Thus, in expert hands it is a useful tool that enables the physician to decide on the best treatment (endoscopic or surgical) and management. Current evidence suggests that it should be used routinely for patients at increased risk for digestive neoplastic lesions and could become the standard of care in the near future, at least in referral centers. However, adequate training programs to promote the implementation of narrow-band imaging in daily clinical practice are needed. In this review, we summarize the current scientific evidence on the clinical usefulness of narrow-band imaging in the diagnosis and characterization of digestive tract lesions/cancers and describe the available classification systems.

Endoscopic microanatomy of the normal gastrointestinal mucosa with narrow band technology and magnification

The development of high-definition endoscopes with optical zoom, along with the use of the digital chromoendoscopy and staining, has given endoscopists the possibility to study the microanatomy of the gastrointestinal mucosa in vivo. The recognition of the changes in the microstructure of the surface and microvascular architecture such as those that occur in neoplastic lesions allow us to characterize these lesions in order to decide on the best course of clinical action. The current greater availability of endoscopes with optical zoom in western countries has allowed the use of this technology in routine clinical practice to spread. In this article we review the basic concepts of magnifying endoscopy and the normal endoscopic microanatomy of the oesophageal, gastric, duodenal, ileal and colonic mucosa.

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

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

Differentiated-type predominant mixed-histology-type early gastric cancer is a significant risk factor for endoscopic non-curative resection regardless of tumor size

This Editorial refers to the article by Y. Horiuchi, p 624‐632 of this issue.

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

BACKGROUND AND AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Protoporphyrinogen oxidase is involved in the fluorescence intensity of 5-aminolevulinic acid-mediated laser-based photodynamic endoscopic diagnosis for early gastric cancer

BACKGROUND/AIM

Laser-based photodynamic endoscopic diagnosis (LPDED) is a type of endoscopic diagnosis that uses the fluorescence caused by the photochemical reaction that occurs when a fluorescent substance is irradiated by a light of a specific wavelength. Although 5-aminolevulinic acid (5-ALA) can detect early gastric cancer (EGC) during LPDED, there is an unresolved issue of the differences in fluorescence intensity among histopathological types of gastric cancer. Thus, the aim of the present study was to assess whether protoporphyrinogen oxidase (PPOX), involved in the activation of protoporphyrin IX, can affect the fluorescence intensity in EGC.

METHODS

Thirty-three gastric tumor lesions in 30 patients were assessed by LPDED using a prototype endoscope equipped with a blue laser ray to cause excitation following oral 5-ALA administration. The tumors were then resected by endoscopic submucosal dissection or laparoscopic surgery. PPOX expression was examined immunohistochemically in the excised specimens. To explore the mechanisms of histopathological diversity in PPOX and coproporphyrinogen oxidase (CPOX) expression of EGC, immunohistochemical analysis was performed using 75 surgically resected specimens of diverse EGCs.

RESULTS

Among the 33 lesions, 26 tumors were detectable by LPDED, whereas seven were undetectable. Between the LPDED-positive and negative groups, there was a significant difference in histopathology. The expression of PPOX was higher in tubular adenocarcinoma (tub) than in signet-ring cell carcinoma (sig). There were significant differences in PPOX and CPOX expression scores of the surgically resected specimens among tub, poorly differentiated adenocarcinoma (por), and sig.

CONCLUSION

PPOX protein expression could be involved in the fluorescence intensity of LPDED in EGC, possibly reflecting histopathological features.

Multiple convex demarcation line for prediction of benign depressed gastric lesions in magnifying narrow-band imaging

BACKGROUND AND STUDY AIMS

 With magnifying narrow-band imaging (M-NBI) of the gastric mucosa, a characteristic demarcation line (DL) is occasionally found in non-cancerous depressed lesions. This DL forms multiple convex shapes along the edge of the epithelia of surrounding mucosa. We have termed this novel finding a multiple convex DL (MCDL). In this study, we clarified the prevalence of an MCDL in depressed gastric lesions detected in patients at high risk for gastric cancer and determined the diagnostic yield necessary to distinguish between cancer and non-cancer.

PATIENTS AND METHODS

 This was a post hoc analysis of a multicenter prospective trial. In total, 362 small (≤ 10 mm) depressed lesions were detected in 1353 patients. Presence or absence of a DL in target lesions was evaluated on M-NBI images. The proportion of MCDLs among lesions with a DL was evaluated.

RESULTS

Images of 347 lesions (39 cancerous and 308 non-cancerous) were evaluable. A DL was present in 252/347 lesions (73 %). When the cutoff value for the proportion of MCDLs needed to distinguish non-cancer from cancer was set at two-thirds, an MCDL was observed in 86/252 lesions (34 %). In 86 lesions with an MCDL, 83 (97 %) were non-cancerous. The sensitivity, specificity, positive predictive value, and negative predictive value of an MCDL for non-cancerous lesions were 38 %, 91 %, 97 %, and 19 %, respectively.

CONCLUSIONS

 Presence of an MCDL had high specificity and positive predictive value for non-cancerous lesions. Evaluating the shape of the DL is useful for differentiation between cancer and non-cancerous lesions.

Low yield for non-targeted biopsies of the stomach and esophagus during elective esophagogastroduodenoscopy

BACKGROUND AND STUDY AIMS

 Biopsies of non-specific mucosal findings are often performed during esophagogastroduodenoscopy (EGD). We sought to determine the prevalence and clinical utility of non-targeted biopsies of the stomach and esophagus.

PATIENTS AND METHODS

 We conducted a retrospective review of 949 outpatient EGDs performed at a US tertiary referral center. Non-targeted biopsies of the stomach were defined as either "normal" or "mild" to "moderate" "erythema" or "inflammation" without other endoscopic features. Non-targeted biopsies of the esophagus and gastroesophageal junction (GEJ) were defined as endoscopically "normal" mucosa. The primary outcome was the proportion of non-targeted biopsies resulting in "definite management change." Secondary outcomes included histopathologic diagnoses of Helicobacter pylori, intestinal metaplasia and esophageal eosinophilia.

RESULTS

 Of 949 EGDs, 332 (35.0 %, 95 % CI 31.9 - 38.1 %) had a non-targeted biopsy taken at any site. Erythema in the gastric body and antrum was biopsied at a rate of 83 - 86 %, while biopsies of "normal"-appearing mucosa occurred at rates from 3 % (GEJ) to 15 % (body and antrum). The percentage of non-targeted biopsies that led to definite management change ranged from 5 % in the GEJ and esophagus to 9 % in the antrum, but did not significantly differ by mucosal appearance. Multivariable regression analyses suggested associations of language and age > 50 with management change from non-targeted gastric biopsy.

CONCLUSIONS

 Non-targeted biopsies of the stomach and esophagus led to definite management change in a small proportion of patients. Further studies are needed to identify patient and/or endoscopic characteristics and techniques to improve the yield of this practice.

Polish Consensus on Treatment of Gastric Cancer; update 2017

The "Polish Research on Gastric Cancer" project has been continued since 1986. The main aim of this project, which is a multicenter and interdisciplinary research, is enhancing the treatment results of gastric cancer patients by developing and promoting the use of optimal methods for diagnosis and treatment, both surgical as well as combined. One of the more important achievements of the project is the development and publication of a document named "Polish Consensus on Treatment of Patients with Gastric Cancer", whose first version was published in 1998. Following versions were updated adequately to changing trends in the proceedings in patients with gastric cancer. A scientific symposium on "Polish Consensus on Treatment of Gastric Cancer - update 2016" was held in 3-4 June 2016 in Cracow. During the symposium a panel session was held during which all authors publicly presented the Consensus assumptions to be discussed further. Moreover, the already mentioned session was preceded by a correspondence as well as a working meeting in order to consolidate the position. It has to be underlined that the directions and guidelines included in the Consensus are not the arbitrarily assumed rules of conduct in a legal aspect and as such every doctor/team of doctors is entitled to make different decisions as long as they are beneficial to a patient with gastric cancer. The Consensus discusses as follows: a) recommended qualifications (stage of advancement, pathological, lymph node topography and the extent of lymphadenectomy, division of cancer of the gastroesophageal junction), b) rules for diagnostics including recommendations regarding endoscopic examination and clinical evaluation of the advancement stage, c) recommendations regarding surgical treatment (extent of resection, extent of lymphadenectomy, tactics of proceedings in cancer of the gastroesophageal junction), d) recommendations regarding combined treatment with chemotherapy or radiotherapy, e) place of endoscopic and less invasive surgery in the treatment of gastric cancer. This publication is a summary of the arrangements made in the panel session during the abovementioned scientific symposium in Cracow in 2016.

Evaluation of image-enhanced endoscopic technology using advanced diagnostic endoscopy for the detection of early gastric cancer: a pilot study

BACKGROUND AND STUDY AIMS

Image-enhanced endoscopy (IEE) plays an important role in early detection and detailed examination of early gastric cancer (EGC). The current study aimed to clarify the efficacy of IEE using advanced diagnostic endoscopy for EGC detection without magnification.

PATIENTS AND METHODS

We performed endoscopic examinations without magnification in patients referred to our hospital with a diagnosis of upper gastrointestinal tumor detected through routine screening endoscopy. In this study, we used three IEE technologies: narrow-band imaging; blue laser imaging; and i-scan optical enhancement. The detection rates for EGC between IEE and white-light imaging (WLI) were compared.

RESULTS

Between July 2013 and June 2014, 156 patients were enrolled. Among upper gastrointestinal tumors, we analyzed endoscopic examination results of 119 lesions that were histologically diagnosed as EGC in 109 patients. The EGC detection rate in the IEE plus WLI groups was 77.3 %. Although the EGC detection rate in the IEE group was higher than that in the WLI group (80.0 % vs. 70.3 %), there was no significant difference between these two modalities. An important detection factor using IEE was tumor circumference, where the rate of detection in the anterior wall and lesser curvature was significantly higher than that in the posterior wall and greater curvature ( P  = 0.046). An important detection factor using WLI was color variation, where the rate of occurrence of a reddened or pale tumor was significantly higher than that of normal colored tumors ( P  = 0.030).

CONCLUSIONS

The detection rate of EGC without magnification was similar between the IEE group and the WLI group. Important detection factors differed between IEE and WLI; therefore, the IEE and WLI modalities have different characteristics regarding EGC detection. Consequently, we propose to use both IEE and WLI in the evaluation of EGC.

Interobserver agreement in detection of "white globe appearance" and the ability of educational lectures to improve the diagnosis of gastric lesions

BACKGROUND

White globe appearance (WGA) refers to a small white lesion of globular shape underneath cancerous gastric epithelium that can be clearly visualized by magnifying endoscopy with narrowband imaging (M-NBI). WGA has been reported to be a novel endoscopic marker that is highly specific in differentiating early gastric cancer (GC) from low-grade adenoma, and has a significantly higher prevalence in early GCs than in noncancerous lesions. However, interobserver agreement in detecting WGA and whether training intervention can improve diagnostic accuracy are unknown.

METHODS

Twenty sets of M-NBI images were examined by 16 endoscopists. The endoscopists attended a lecture about WGA, and examined the images again after the lecture. Interobserver agreement in detecting WGA in the second examination and increases in the proportion of correct diagnoses and the degree of confidence of diagnoses of cancerous lesions were evaluated.

RESULTS

The kappa value for interobserver agreement in detecting WGA in the second examination was 0.735. The proportion of correct diagnoses was significantly higher in the second examination compared with the first examination when WGA was present (95.5% vs 55.4%; P < 0.001), but not when WGA was absent (61.6% vs 52.7%; P = 0.190). The proportion of correct diagnoses with a high degree of confidence was significantly higher in the second examination, both with WGA (91.1% vs 29.5%; P < 0.001) and without WGA (36.6% vs 20.5%; P = 0.031).

CONCLUSIONS

The detection of WGA by endoscopists was highly reproducible. A brief educational lecture about WGA increased the proportion of correct diagnoses and the degree of confidence of diagnoses of GC with WGA.

Endoscopic Management of Early Gastric Adenocarcinoma and Preinvasive Gastric Lesions

Early gastric cancer (ECG) can be difficult to diagnose endoscopically. Endoscopists should be familiar with subtle changes and endoscopic features of EGC. Chromoendoscopy and image-enhanced endoscopy improve diagnostic accuracy and facilitate endoscopic resection. Endoscopic submucosal dissection is a preferred endoscopic technique for resection of EGC and offers a comparable overall survival to surgical resection. Endoscopic management of benign gastric epithelial polyps (fundic gland polyps, hyperplastic polyps, and gastric adenoma) depends on patient symptomatology, patient's comorbidities (eg, familial syndromes), lesions' characteristics, and risk of malignant transformation. This article provides an overview of endoscopic management of EGC and common premalignant gastric lesions.

Past and current trends in endoscopic diagnosis for early stage gastric cancer in Japan

Methodology for the diagnosis and staging of early gastric cancer (EGC) has improved in Japan since the development of the gastro-camera and determination of a definition of EGC. Imaging technology has been steadily evolving in the endoscopy field. Improvements in the resolution of standard endoscopy images used in screening and surveillance provide greater opportunities to find gastric cancer earlier. Image enhancement endoscopy (IEE), such as narrow band imaging (NBI), highlights mucosal structures and vascularity. In particular, when NBI is used with magnifying endoscopy, it reveals fine details of subtle superficial abnormalities of EGC that are difficult to recognize using standard white light endoscopy. IEE-assisted magnifying endoscopy has improved the accuracy of the differentiation of superficial gastric cancer as well as delineation of the diseased mucosa. The advanced imaging technology enables precise assessment of the risk of lymph node metastasis of EGC and is widely used to determine indications for endoscopic treatment. It is not an overstatement to say that this has become the basis for the current development and dissemination of endoscopic treatments. Moreover, the resolution of endoscopic imaging has been upgraded to the microscopy level by the development of endomicroscopy, including endocytoscopy and confocal laser endomicroscopy. Endomicroscopy allows real-time histological analysis of living tissue during routine endoscopy and may reduce the number of biopsies needed to reach the correct diagnosis, minimizing the risk of sampling errors.

Advanced endoscopic imaging in gastric neoplasia and preneoplasia

Conventional white light endoscopy remains the current standard in routine clinical practice for early detection of gastric cancer. However, it may not accurately diagnose preneoplastic gastric lesions. The technological advancements in the field of endoscopic imaging for gastric lesions are fast growing. This article reviews currently available advanced endoscopic imaging modalities, in particular chromoendoscopy, narrow band imaging and confocal laser endomicroscopy, and their corresponding evidence shown to improve diagnosis of preneoplastic gastric lesions. Raman spectrometry and polarimetry are also introduced as promising emerging technologies.

Risk factors associated with difficult gastric endoscopic submucosal dissection: predicting difficult ESD

BACKGROUND AND STUDY AIM

Endoscopic submucosal dissection (ESD) is a widely accepted treatment for superficial gastric neoplasms. Difficult ESD can lead to complications, such as bleeding and perforation. To predict difficult ESD procedures, we analyzed the factors associated with difficult ESD.

PATIENTS AND METHODS

The medical records of 1052 ESD procedures were retrospectively reviewed. Difficult ESD was defined by any one of three end points: longer procedure time (≥60 min), piecemeal resection, incomplete (R1) resection, or gastric wall perforation. To determine the factors associated with difficult ESD, clinical and pathologic features and endoscopic findings were analyzed.

RESULTS

The rates of en bloc resection and curative (R0) resection were 93.3 and 92.4 %, respectively. The mean procedure time was 27.7 ± 16.7 min. After multivariate analysis, larger tumor size (≥20 mm) was an independent risk factor for longer procedure time (OR 4.1, P < 0.001), for piecemeal resection (OR 2.3, P = 0.003) and incomplete (R1) resection (OR 2.1, P = 0.005). Location of the lesion (upper third) was an independent risk factor for longer procedure time (OR 5.8, P < 0.001), for piecemeal resection (OR 4.1, P < 0.001) and incomplete (R1) resection (OR 4.5, P < 0.001). Submucosal fibrosis was an independent risk factor for longer procedure time (OR 9.7, P < 0.001), for piecemeal resection (OR 2.4, P < 0.001) and incomplete (R1) resection (OR 2.6, P < 0.001). Finally, submucosal invasive gastric cancer was an independent risk factor for piecemeal resection (OR 2.6, P = 0.008), for perforation (OR 19.3, P = 0.001) and for incomplete (R1) resection (OR 2.7, P = 0.001).

CONCLUSIONS

Difficult ESD procedures are a function of the lesion size and location, submucosal fibrosis, and submucosal invasive cancer. When a difficult ESD procedure is expected, appropriate preparations should be considered, including consultation with more experienced endoscopists.

Elevated amino acids in gastric juice as potential biomarkers for gastric cancer

Early diagnosis plays a vital role in the improvement of the curative rate of gastric cancer. However, the poor specificity and sensitivity of traditional gastric cancer biomarkers, such as carcino-embryonic antigen and carbohydrate antigen 199, make it difficult to screen early gastric cancer. Gastric juice amino acid profile may be an alternative tumor marker, since abnormal elevation of amino acids in gastric juice has been reported in precancerous patients. Normal concentration of amino acids is extremely low in gastric juice, and special techniques are required to detect amino acids in gastric juice. The change of amino acids in gastric juice is more significant than in blood and tumor tissue. The amino acid profile in gastric juice may work as efficient biomarkers for gastric cancer with the development of amino acid detection technique.