Electronic Chromoendoscopy Research Articles

How to optimize the detection of serrated lesions: old tools for a new story?

In the last two decades, we have witnessed impressive and very quick technological advances in colonoscopy imaging aimed at optimizing the detection of neoplastic lesions. All major colonoscope manufacturers have integrated these innovations into the latest generation colonoscopes and currently produce high definition (HD) imaging systems with one or more push-the-button electronic chromoendoscopy technologies that are able to enhance visualization of the mucosal vasculature and/or architecture, so enhancing the contrast between lesions and the surrounding normal mucosa.

Surveillance in Barrett’s Esophagus: Challenges, Progress, and Possibilities

Endoscopic surveillance of Barrett's esophagus, aiming to detect prevalent dysplasia and adenocarcinoma, followed by effective endoscopic treatment, is an integral part of the esophageal adenocarcinoma prevention paradigm. However, several limitations, such as the subtle appearance of dysplasia, sampling error (inherent in current surveillance protocols), and noncompliance with surveillance recommendations, lead to missed dysplasia and neoplasia, reducing the effectiveness of surveillance as currently practiced. Careful endoscopic assessment with high-resolution white-light endoscopy, dye-based or electronic chromoendoscopy, and comprehensive sampling of the BE mucosa, remains the cornerstone of endoscopic surveillance. Emerging innovations in this area span the gamut of more efficient sampling methods, advanced imaging tools, artificial intelligence, and molecular marker-powered approaches as adjuncts, to identify prevalent and predict incident dysplasia or adenocarcinoma. Development and implementation of validated quality indicators will allow additional advancement of this critical field. These approaches will hopefully enable efficient and effective cancer prevention and treatment.

WEO Newsletter.

WEO Newsletter.

New endoscopic tools in inflammatory bowel disease.

Endoscopic remission is now considered the ultimate long-term goal for treating inflammatory bowel disease (IBD). Recent advances in endoscopic techniques have progressively added new tools to the armamentarium of endoscopists for a deeper assessment and characterisation of the intestinal mucosa. Virtual Electronic chromoendoscopy is widely available in the endoscopic units, leading to a more accurate evaluation of the vascular and mucosal architecture of the colon, reducing the gap with histology, which is considered a favourable long-term measure. In addition, advanced, sophisticated techniques such as endocytoscope and confocal laser endomicroscopy provide insights into individualised and personalised IBD therapy. Finally, high expectations are placed on the advent of Artificial Intelligence (AI) with promising applications that have the potential to revolutionise IBD diagnosis and management. Here, we discuss state-of-the-art of endoscopic techniques and their applicability to accurate assess endoscopic and histological remission, predict response to therapy and detect, characterise and guide treatment of colonic dysplastic lesions. We are seeing the dawn of a new era wherein the applications of these new endoscopic tools, hand in hand with AI, offer the most incredible opportunity to deliver precision medicine to patients with IBD.

Image-enhanced endoscopy and endoscopic resection practices in the colon among endoscopists in India.

Background and study aims Clinical practice patterns for image-enhanced endoscopy (IEE) and colonic endoscopic resection practices vary among endoscopists. We conducted a survey to understand the differences in IEE and colonoscopic resection practices among endoscopists from India. Methods An online cross-sectional survey comprising 40 questions regarding quality control of colonoscopy, IEE, and colonic endoscopic resection practices was circulated through the registry of the Indian Society of Gastroenterology and Association of Colon and Rectal Surgeons of India. Participation was voluntary and response to all questions was compulsory. Results There were 205 respondents to the survey (93.2 % gastroenterologists, 90.2 % male, 54.6 % aged 30 to 40 years, 36.1 % working in academic institution, 36.1 % working in corporate hospitals). Of the endoscopists, 50.7 % had no training in IEE and 10.7 % performed endoscopy on systems without any IEE modalities. Endoscopists with more experience were more likely to use IEE modalities in practice routinely ( P = 0.007). Twenty percent never used IEE to classify polyps. Sixty percent of respondents did not use dye-chromoendoscopy. Less experienced endoscopists used viscous solutions as submucosal injectate ( P = 0.036) more often. Of the respondents, 44 % never tattooed the site of endoscopic resection. Ablation of edges post-endoscopic mucosal resection was not done by 25.5 % respondents. Most respondents used electronic chromoendoscopy (36.1 %) or random four-quadrant sampling (35.6 %) for surveillance in inflammatory bowel disease. Surveillance post-endoscopic resection was done arbitrarily by 24 % respondents at 6 months to 1 year. Conclusions There are several lacunae in the practice of IEE and colonic endoscopic resection among endoscopists, with need for programs for privileging, credentialing and proctoring these endoscopic skills.

External validation of the Paddington International Virtual Electronic ChromoendoScopy ScOre as a good endoscopic score to define mucosal healing and predict long‐term clinical outcomes in ulcerative colitis

To define endoscopic and histological remission in ulcerative colitis (UC) accurately, several scoring systems have been established. A novel virtual electronic chromoendoscopy score, the Paddington International Virtual ChromoendoScopy ScOre (PICaSSO), was developed, validated, and reproduced to assess inflammation grade and predict patient prognosis. We externally verified and validated the clinical value of PICaSSO in UC patients. This prospective study enrolled 63 UC patients. The Mayo endoscopic score (MES), UC Endoscopic Index of Severity (UCEIS), and PICaSSO were adopted for endoscopic evaluation. All biopsy samples were scored using the Robarts histological index (RHI), Nancy histological index (NHI), and "Extent, Chronicity, Activity, Plusadditional findings" (ECAP) score. Patients with an endoscopic MES of 0-1 at baseline were followed up during a median time of 23.5 months. PICaSSO wasstrongly correlated with other endoscopic and histological scoring systems. PICaSSO ≤3 had advantages in assessing histological remission (HR), with the highest accuracy of 88.9% for ECAP-HR. Relapse-free survival rates were significantly different between patients with MES 0 and MES 1 and patients with PICaSSO ≤3 and >3 (P=0.010 and 0.018, respectively). PICaSSO was externally validated with strong correlations with other endoscopic and histological scoring systems in UC, and PICaSSO-ER might potentially predict a better long-term clinical outcome in UC patients.

Artificial Intelligence Allows Leaving-In-Situ Colorectal Polyps

Artificial Intelligence (AI) could support cost-saving strategies for colonoscopy because of its accuracy in the optical diagnosis of colorectal polyps. However, AI must meet predefined criteria to be implemented in clinical settings. An approved computer-aided diagnosis (CADx) module for differentiating between adenoma and nonadenoma in unmagnified white-light colonoscopy was used in a consecutive series of colonoscopies. For each polyp, CADx output and subsequent endoscopist diagnosis with advanced imaging were matched against the histology gold standard. The primary outcome was the negative predictive value (NPV) of CADx for adenomatous histology for ≤5-mm rectosigmoid lesions. We also calculated the NPV for AI-assisted endoscopist predictions, and agreement between CADx and histology-based postpolypectomy surveillance intervals according to European and American guidelines. Overall, 544 polyps were removed in 162 patients, of which 295 (54.2%) were ≤5-mm rectosigmoid histologically verified lesions. CADx diagnosis was feasible in 291 of 295 (98.6%), and the NPV for ≤5-mm rectosigmoid lesions was 97.6% (95% CI, 94.1%-99.1%). There were 242 of 295 (82%) lesions that were amenable for a leave-in-situ strategy. Based on CADx output, 212 of 544 (39%) would be amenable to a resect-and-discard strategy, resulting in a 95.6% (95% CI, 90.8%-98.0%) and 95.9% (95% CI, 89.8%-98.4%) agreement between CADx- and histology-based surveillance intervals according to European and American guidelines, respectively. A similar NPV (97.6%; 95% CI, 94.8%-99.1%) for ≤5-mm rectosigmoids was achieved by AI-assisted endoscopists assessing polyps with electronic chromoendoscopy, with a CADx-concordant diagnosis in 97.2% of cases. In this study, CADx without advanced imaging exceeded the benchmarks required for optical diagnosis of colorectal polyps. CADx could help implement cost-saving strategies in colonoscopy by reducing the burden of polypectomy and/or pathology. gov registration number: NCT04884581.

Strengths and Weaknesses of an Artificial Intelligence Polyp Detection Program as Assessed by a High-Detecting Endoscopist

Strengths and Weaknesses of an Artificial Intelligence Polyp Detection Program as Assessed by a High-Detecting Endoscopist

Reproducibility of the electronic chromoendoscopy PICaSSO score (Paddington International Virtual ChromoendoScopy ScOre) in ulcerative colitis using multiple endoscopic platforms: a prospective multicenter international study (with video)

Endoscopic and histologic remission (HR) are key therapeutic targets in the management of ulcerative colitis (UC). The aim of this study was to evaluate the reproducibility of the Paddington International virtual ChromoendoScopy ScOre (PICaSSO), a virtual chromoendoscopy score originally validated by use of the iSCAN platform, with the narrow-band imaging (NBI), linked-color imaging (LCI), and blue-laser imaging (BLI) platforms. We evaluated endoscopic activity using the Mayo Endoscopic Score (MES), the Ulcerative Colitis Endoscopic Index of Severity (UCEIS), and PICaSSO in 159 UC patients (78 NBI and 81 BLI/LCI) who underwent colonoscopy in 2 tertiary referral centers. HR was defined by the Robarts Histopathology Index (RHI) and the Nancy Histologic Index (NHI). Receiver operating characteristic curves were plotted to evaluate endoscopic scores for the prediction of HR. Intraclass correlation coefficients (ICC) between endoscopists were evaluated. PICaSSO had an ICC of 0.825 when the NBI and BLI/LCI cohorts were combined, higher than MES and UCEIS. The correlation between PICaSSO and RHI and NHI was 0.83 and 0.79 in the NBI cohort and between 0.63 and 0.65 in LCI/BLI. In the NBI cohort, the accuracy of MES, UCEIS, and PICaSSO was 0.936, 0.897, and 0.808 for HR measured by RHI and 0.897, 0.885, and 0.821 by NHI, respectively. In the BLI/LCI cohort, the accuracy of MES, UCEIS, LCI PICaSSO and BLI PICaSSO was 0.765, 0.778, 0.827, and 0.79 to predict HR with RHI and NHI, respectively. The PICaSSO score can be consistently and accurately reproduced with NBI and LCI/BLI and therefore can be applied to all virtual electronic chromoendoscopy platforms.

DOP18 Advanced optical diagnosis technology for assessment of endoscopic and histological remission in Ulcerative Colitis: A systematic review and meta-analysis

Abstract Background Advanced endoscopic technologies led to significant progress in the definition of endoscopic remission of ulcerative colitis (UC), and correlate better with histological changes, compared to standard endoscopy. However, whilst studies have assessed the diagnostic accuracy of endoscope technologies individually, there is current limited data comparing between technologies. As such, we aimed to compare the correlations between endoscopy and histology disease activity scores across endoscope technologies Methods We searched PubMed and Embase in January 2021 for eligible studies reporting the correlation between endoscopy and histology activity scores in UC. Studies were grouped by endoscope technology as standard-definition white light (SD-WLE), high-definition white light (HD-WLE), or electronic virtual chromoendoscopy (VCE), and comparisons made between these groups Results A total of N=27 studies were identified, of which N=12 were included in a meta-analysis of correlations between endoscopic and histological activity scores. Combining these returned a pooled correlation coefficient (rho) for the SD-WLE group of 0.61, which did not differ significantly from HD-WLE (rho: 0.79, p=0.140) or VCE (rho: 0.70, p=0.471) [Fig 1a]. In addition, N=4 studies reported the accuracy of endoscopic activity scores on WLE and VCE to diagnose histological remission. Pooling these found significantly higher accuracy for VCE, compared to WLE (risk ratio: 1.13, 95% CI: 1.07–1.19, p<0.001).[Fig 1b] Conclusion Activity scores assessed using endoscopy are strongly correlated with activity on histology. VCE appears to have better accuracy for the diagnosis of histological remission in UC, compared to WLE.

Electronic chromo-endoscopy: technical details and a clinical perspective.

Precise endoscopic assessment is necessary to detect neoplastic changes in an early stage. Electronic or virtual chromo-endoscopy (ECE) is an alternative to conventional dye-based chromo-endoscopy which markedly improves capillary pattern and hence can detect micro-vessel morphological changes of early neoplasia to target biopsies and aid in diagnosis. The clinical significance increased after the advent of endoscopic treatment modalities like ESD/EMR which requires precise delineation of extent and depth of lesion. Most of the studies have used narrow-band imaging (NBI) (Olympus Medical Systems Tokyo, Japan), although data from i-SCAN (PENTAX Endoscopy, Tokyo, Japan) and flexible spectral imaging color enhancement (FICE) (Fujinon, Fujifilm Medical Co, Saitama, Japan) are emerging. Electronic chromo-endoscopy is convenient compared to dye-based chromo-endoscopy in the sense that it is available at the push of a button in endoscope and reduces procedure time substantially with comparable efficacy. Scope of this review is to discuss available electronic chromo-endoscopy modalities and their role in the diagnosis, surveillance, and management of early GI neoplasia.

Advanced technology for assessment of endoscopic and histological activity in ulcerative colitis: a systematic review and meta-analysis.

Background:Advanced endoscopic technologies led to significant progress in the definition of endoscopic remission of ulcerative colitis (UC) and correlate better with histological changes, compared with standard endoscopy. However, while studies have assessed the diagnostic accuracy of endoscope technologies individually, there are currently limited data comparing between technologies. As such, the aim of this systematic review was to pool data from the existing literature and compare the correlations between endoscopy and histologic disease activity scores across endoscope technologies.Methods:We searched PubMed and Embase until February 2021 for eligible studies reporting the correlation between endoscopy and histology activity scores in UC. Studies were grouped by endoscope technology as standard-definition white light (SD-WLE), high-definition white light (HD-WLE) or electronic virtual chromoendoscopy (VCE) and comparisons made between these groups.Results:A total of N = 27 studies were identified, of which N = 12 were included in a meta-analysis of correlations between endoscopic and histological activity scores. Combining these studies identified considerable heterogeneity (I2: 89–93%) and returned a pooled correlation coefficient (ρ) for the SD-WLE group of 0.74, which did not differ significantly from HD-WLE (ρ: 0.65, p = 0.521) or VCE (ρ: 0.70, p = 0.801). In addition, N = 4 studies reported the accuracy of endoscopic activity scores on WLE and VCE to diagnose histological remission. Pooling these found significantly higher accuracy for VCE, compared with WLE [risk ratio: 1.13, 95% confidence interval (CI): 1.07–1.19, p < 0.001].Conclusion:Activity scores assessed using endoscopy are strongly correlated with activity on histology regardless of endoscopic technology. VCE seems to be more accurate in predicting histological remission than WLE. However, given the heterogeneity between the included studies, head-to-head trials are warranted to confirm these findings.

S273 Two Withdrawals During Colonoscopy Are Better Than One in Lynch Syndrome: A Systematic Review and Meta-Analysis

Introduction: Lynch syndrome is being increasingly diagnosed with wider availability of genetic testing and increasing prevalence of young-onset colorectal cancers. Missed adenomas are a particular concern because of high risk of interval colon cancers in Lynch syndrome. The aim of this study was to report on the adenoma detection rate (ADR) and adenoma miss rate (AMR) during first pass and second pass colonoscopy in patients with Lynch syndrome. Methods: Electronic literature search was performed using SCOPUS, MEDLINE, and COCHRANE LIBRARY (Inception to March 2021) for randomized controlled trials (RCT) of advanced imaging during colonoscopy in patients with Lynch syndrome. Inclusion criteria were: 1) history of genetically proven Lynch syndrome or satisfaction of the Amsterdam Criteria, 2) performance of tandem colonoscopies (either dye-based chromoendoscopy and white light endoscopy (WLE) or electronic chromoendoscopy and WLE, in any order) and 3) reporting of adenoma detection rate. Outcomes of interest were adenoma detection rates (ADR) of two versus one withdrawal and adenoma miss rates of one withdrawal. Pooled relative risk (RR) for outcomes of interest were analyzed using Review Manager version 5.3. Results: Of the 15 citations reviewed, six RCT were eligible. A total of 436 subjects (average age: 43.6 years, 55% females) underwent tandem examination of colon: dye-based chromoendoscopy (N = 267) and electronic chromoendoscopy (N = 261) alternating with WLE in any order. The two withdrawals had higher ADR compared to one withdrawal irrespective of the method of the initial withdrawal: pooled RR 1.67 (95% CI: 1.34-2.07; I2 = 0%) (Panel A). Comparing the yield of two withdrawals with only the first withdrawal, the adenoma miss rate of the first withdrawal was 64.7% (95% CI: 58.4%-70.5%; I2 = 22%) (Panel B). If the first withdrawal was dye-based chromoendoscopy, then the adenoma miss rate was lower compared to those patients where the first withdrawal was with electronic chromoendoscopy (36.8% versus 63.1%; pooled RR 1.68, 95% CI: 0.94-2.91; I2 = 85%). Conclusion: The adenoma miss rate of a single withdrawal during colonoscopy in patients with Lynch syndrome is greater than 50%. Endoscopists should consider performing a second withdrawal in this high-risk population.Figure 1.: A. Forest plot of ADR among subjects with colon examination by two withdrawals compared to single withdrawal using any modality. B. Forest plot of AMR of colon examination by single withdrawal when colon examination was performed with second withdrawal by any modality.

THE IMPACT OF COLORECTAL CHROMENDOSCOPY WITH ENHANCED MUCOSAL IMAGING ON ADENOMA MISS RATE IN SCREENING COLONOSCOPY.

Colonoscopy is the gold standard for the diagnosis and treatment of adenomas. It is related with decreased colorectal cancer incidence and mortality. However, an important problem is missed colorectal adenoma. All efforts should be undertaken to reduce this rate. Enhancing imaging technologies including electronic chromoendoscopy and magnification has been increasingly adopted for improving the colorectal neoplasia detection rate and the detailed study of its surface, as well. I-scan images (Pentax, Tokyo, Japan) provides virtual chromoendoscopy in real-time during the examination to view the surface pattern, highlighting the microvasculature of the neoplastic lesion. The evidence on the impact of the use of I-scan on the colorectal adenoma detection rate is scarce. To evaluate whether the use of I-scan has impact on the adenoma miss rate (AMR) of screening colonoscopy exams. Observational and prospective study conducted by monitoring patients over 50 years undergoing colonoscopy. There were two groups: Group 1 - first inspection with standard high-definition white-light (HDWL) followed by a second inspection with I-scan 1; Group 2 - first inspection with I-scan 1 followed by a second inspection with standard HDWL. The primary outcome was the AMR from the first exam, calculated with the number of adenomas detected in the second exam, divided by the total number of adenomas detected in both exams. A total of 85 patients participated in the study. 14 were excluded, with a final sample of 71 patients, in the Group 1, 34 patients, and the Group 2, 37. A total of 58 adenomas were detected, 40 in the first inspection (20 in each group) and 18 in the second inspection in group 1. The overall AMR was higher for the Group 1 than the Group 2 (47.4% vs 0% P=0.0002). The use of I-scan 1 during colonoscopy exam reduces the AMR.

OP10 Response to biologics in IBD patients assessed by Computerized image analysis of Probe Based Confocal Laser Endomicroscopy with molecular labeling and gene expression profiling

Abstract Background Biologics are being used increasingly in the treatment of Inflammatory Bowel Disease. However, up to 40% of patients do not respond to biologics. Therefore, methods to predict response are imperative. We aimed to identify novel genes and pathways predictive of anti-TNF response in patients with Ulcerative Colitis (UC) undergoing electronic chromoendoscopy and probe confocal laser endomicroscopy (pCLE). We further evaluated the ex-vivo binding of fluorescent labelled biologics as markers of response Methods 26 UC patients starting anti-TNF therapy as standard of care were recruited. Pre-treatment colonoscopy, with electronic chromoendoscopy and pCLE (Cellvizio, Mauna Kea) by injecting intravenous fluorescein (2.5-5mls), was performed to assess disease activity. Targeted biopsies were taken for fluorescein isothiocyanate (FITC)-labelled infliximab staining and RNA extraction and gene expression analysis. Ex vivo labelling was evaluated by an automated analysis: after a first pre-processing step to remove biases, the labelled regions were identified using statistical multi-level thresholding, and evaluated as area and intensity. To assess response, the same endoscopic procedure was repeated at week 12–14 after anti-TNF. cDNA libraries were prepared using QIAseq UPX 3’Transcriptome reagents and sequenced. Normalised gene expressions were obtained through the CLC Genomics Workbench. Differentially expressed genes (DEGs) (FDR-corrected P-value&amp;lt;0.05) were determined using the Limma package and PLS-DA modelling performed to calculate their importance (VIP score). Functionally related genes were identified and classified using DAVID tools. Strongest indicators of response were predicted by Random Forest area under the curve (AUC) analysis in this cohort and a similar validation cohort Results At baseline increased binding of the labelled biologic was associated with a higher likelihood of response to treatment (AUROC81%, accuracy77%, PPV100%, NPV63%). 342 DEGs (75 up-regulated, 267 down-regulated) distinguished responders from non-responders, 76 fell within enriched pathways. Pathways related to inflammation, chemotaxis, TGF-beta signalling, extracellular matrix and carbohydrate metabolism were reduced and cell-cell adhesion increased in responders pre-treatment. Among the 37 genes with VIP&amp;gt;1, CRIP2, CXCL6,EMILIN1,GADD45B, LAMA4 and MAPKAPK2 were upregulated in non-responders pre-treatment and were good predictors of response (AUROC&amp;gt;0.7) in this cohort and validation cohort Conclusion A higher mucosal binding of the biologics before treatment was observed in anti-TNF responders. Responsive UC patients have a less inflamed and fibrotic state pre-treatment. Chemotactic pathways, involving CXCL6 may be novel targets to treat non-responders

Artificial Intelligence and Its Role in Identifying Esophageal Neoplasia.

Randomized trials have demonstrated that ablation of dysplastic Barrett's esophagus can reduce the risk of progression to cancer. Endoscopic resection for early stage esophageal adenocarcinoma and squamous cell carcinoma can significantly reduce postoperative morbidity compared to esophagectomy. Unfortunately, current endoscopic surveillance technologies (e.g., high-definition white light, electronic, and dye-based chromoendoscopy) lack sensitivity at identifying subtle areas of dysplasia and cancer. Random biopsies sample only approximately 5% of the esophageal mucosa at risk, and there is poor agreement among pathologists in identifying low-grade dysplasia. Machine-based deep learning medical image and video assessment technologies have progressed significantly in recent years, enabled in large part by advances in computer processing capabilities. In deep learning, sequential layers allow models to transform input data (e.g., pixels for imaging data) into a composite representation that allows for classification and feature identification. Several publications have attempted to use this technology to help identify dysplasia and early esophageal cancer. The aims of this reviews are as follows: (a) discussing limitations in our current strategies to identify esophageal dysplasia and cancer, (b) explaining the concepts behind deep learning and convolutional neural networks using language appropriate for clinicians without an engineering background, (c) systematically reviewing the literature for studies that have used deep learning to identify esophageal neoplasia, and (d) based on the systemic review, outlining strategies on further work necessary before these technologies are ready for "prime-time," i.e., use in routine clinical care.

Comparing endoscopic interventions to improve serrated adenoma detection rates during colonoscopy: a systematic review and network meta-analysis of randomized controlled trials.

Serrated lesions (sessile serrated adenomas/polyps and traditional serrated adenomas) owing to their subtle appearance and proximal location have a high miss rate. The objective of this study is to compare all the available endoscopic interventions for improving serrated adenoma detection rate (SADR) through a network meta-analysis. We conducted a systematic review of the available literature (PubMed, Embase, Cochrane and WoS) from inception to 29 November 2019 to identify all the relevant randomized controlled trials. A total of 28 trials with 22 830 patients were included. The studies compared the efficacy of add-on devices (endocap, endocuff, endocuff vision, G-EYE, endorings, AmplifEYE), electronic chromoendoscopy (linked-color imaging, blue laser imaging, narrow band imaging), dye-based chromoendoscopy, full-spectrum endoscopy (FUSE) and water-based techniques (WBT) with each other or high-definition colonoscopy. Both pairwise and network meta-analysis was conducted using the random-effects model. Risk ratios (RR) with 95% confidence intervals (CI) and P-values were calculated. Direct meta-analysis demonstrated superiority for WBT (RR: 1.41, CI: 1.01-1.98), add-on devices (RR: 1.53, CI: 1.13-2.08), narrow band imaging (RR: 1.93, CI: 1.12-3.32) and endocuff vision (RR: 1.87, CI: 1.13-3.11) compared to high-definition colonoscopy. The results were consistent on network meta-analysis with chromoendoscopy as an additional modality for improving SADR (RR: 1.74, CI: 1.03-2.93). In a network meta-analysis, add-on devices (particularly endocuff vision), narrow band imaging, WBT and chromoendoscopy were comparable to each other and improved SADR compared to high-definition colonoscopy.

Chromoendoscopy: role in modern endoscopic imaging.

Detection of early gastrointestinal tract malignancy can be challenging on white light endoscopy especially as lesions can be subtle and inconspicuous. With the advent of electronic chromoendoscopy technologies, lesions which have already been detected can be quickly and "conveniently" characterised. This review will discuss some of the indications and modern applications of chromoendoscopy in various conditions including Barrett's oesophagus, oesophageal squamous cell carcinoma, early gastric cancer, inflammatory bowel disease and neoplastic colonic lesions. In carefully selected situations, chromoendoscopy could still be a useful adjunct to white light endoscopy in day-to-day clinical practice.

What is the optimal surveillance strategy for non-dysplastic Barrett's esophagus?

There is conflicting data on the effectiveness of the currently recommended endoscopic surveillance strategy in non-dysplastic BE patients. We reviewed the literature to evaluate the (cost) effectiveness of the current surveillance strategy. We also reviewed critical strategies and new technologies which could improve dysplasia detection. Adherence to the current EGD surveillance guidelines is suboptimal with high rates of missed dysplasia/EAC. The influence of surveillance on EAC mortality appears modest. Careful cleansing, inspection and sampling of the BE mucosa using high resolution while light and (electronic) chromoendoscopy is critical. Newer sampling techniques coupled with computer aided diagnosis and emerging imaging technologies have shown promise in improving dysplasia detection. Personalized surveillance with risk stratification based on risk factors for progression may be on the horizon. Current BE surveillance strategy will likely be further refined and optimized by emerging new technologies in tissue sampling, advanced imaging and risk stratification.

Current Perspectives in Atrophic Gastritis.

Atrophic gastritis is a complex syndrome with gastric atrophy as a common trait. Helicobacter pylori infection and autoimmunity are the two main contexts in which it develops. It is slightly symptomatic, affects various aspects of general health, and remains a predisposing factor for gastric cancer. This review will update current knowledge and progress on atrophic gastritis. Atrophic gastritis affects mostly adults with persistent dyspepsia, deficient anemia, autoimmunity disease, long-term proton pump inhibitor use, and a family history of gastric cancer. Gastric biopsies, expressed as Sydney system grade and OLGA/OLGIM classifications, represent the gold standard for diagnosis and cancer risk stage, respectively. Recently, electronic chromoendoscopy has allowed "targeted biopsies" of intestinal metaplasia. The associated hypochlorhydria affects the gastric microbiota composition suggesting that non-Helicobacter pylori microbiota may participate in the development of gastric cancer. Physicians should be aware of multifaceted clinical presentation of atrophic gastritis. It should be endoscopically monitored by targeted gastric biopsies. Autoimmune and Helicobacter pylori-induced atrophic gastritis are associated with different gastric microbial profiles playing different roles in gastric tumorigenesis.