Texture and Color Enhancement Imaging Improves Colonic Adenoma Detection: A Multicenter Randomized Controlled Trial.

The global burden of colorectal cancer is expected to increase more than 60% by 2030; however, compelling evidence now shows that the implementation of population screening programs in developed countries has led to a substantial reduction in incidence and mortality.1,2 Despite this, patients continue to develop preventable colorectal cancers, in part because of high rates of interval colon cancer diagnosed after screening or surveillance colonoscopies.3.

Establishment of Standards for the Referral of Large Non-Pedunculated Colorectal Polyps: An International Expert Consensus Using a Modified Delphi Process.

BACKGROUND AND AIMS: Resection of colorectal polyps has been shown to decrease the incidence and mortality of colorectal cancer. Large non-pedunculated colorectal polyps are often referred to expert centres for endoscopic resection, which requires relevant information to be conveyed to the therapeutic endoscopist to allow for triage and planning of resection technique. The primary objective of our study was to establish minimum expected standards for the referral of LNPCP for potential ER. METHODS: A Delphi methodology was employed to establish consensus on minimum expected standards for the referral of large colorectal polyps among a panel of international endoscopy experts. The expert panel was recruited through purposive sampling, and three rounds of surveys were conducted to achieve consensus, with quantitative and qualitative data analysed for each round. RESULTS: A total of 24 international experts from diverse continents participated in the Delphi study, resulting in consensus on 19 statements related to the referral of large colorectal polyps. The identified factors, including patient demographics, relevant medications, lesion factors, photodocumentation and the presence of a tattoo, were deemed important for conveying the necessary information to therapeutic endoscopists. The mean scores for the statements ranged from 7.04 to 9.29 out of 10, with high percentages of experts considering most statements as a very high priority. Subgroup analysis by continent revealed some variations in consensus rates among experts from different regions. CONCLUSION: The identified consensus statements can aid in improving the triage and planning of resection techniques for large colorectal polyps, ultimately contributing to the reduction of colorectal cancer incidence and mortality.

Precision endoscopy in the era of climate change and sustainability.

Global warming caused by increased greenhouse gas (GHG) emissions has a direct impact on human health. Gastrointestinal (GI) endoscopy contributes significantly to GHG emissions due to energy consumption, reprocessing of endoscopes and accessories, production of equipment, safe disposal of biohazardous waste, and travel by patients. Moreover, GHGs are also generated in histopathology through tissue processing and the production of biopsy specimen bottles. The reduction in unnecessary surveillance endoscopies and biopsies is a practical approach to decrease GHG emissions without affecting disease outcomes. This narrative review explores the role of precision medicine in GI endoscopy, such as image-enhanced endoscopy and artificial intelligence, with a focus on decreasing unnecessary endoscopic procedures and biopsies in the surveillance and diagnosis of premalignant lesions in the esophagus, stomach, and colon. This review offers strategies to minimize unnecessary endoscopic procedures and biopsies, decrease GHG emissions, and maintain high-quality patient care, thereby contributing to sustainable healthcare practices.

International consensus on the management of large (≥20 mm) colorectal laterally spreading tumors: World Endoscopy Organization Delphi study.

OBJECTIVES: There have been significant advances in the management of large (≥20 mm) laterally spreading tumors (LSTs) or nonpedunculated colorectal polyps; however, there is a lack of clear consensus on the management of these lesions with significant geographic variability especially between Eastern and Western paradigms. We aimed to provide an international consensus to better guide management and attempt to homogenize practices. METHODS: Two experts in interventional endoscopy spearheaded an evidence-based Delphi study on behalf of the World Endoscopy Organization Colorectal Cancer Screening Committee. A steering committee comprising six members devised 51 statements, and 43 experts from 18 countries on six continents participated in a three-round voting process. The Grading of Recommendations, Assessment, Development and Evaluations tool was used to assess evidence quality and recommendation strength. Consensus was defined as ≥80% agreement (strongly agree or agree) on a 5-point Likert scale. RESULTS: Forty-two statements reached consensus after three rounds of voting. Recommendations included: three statements on training and competency; 10 statements on preresection evaluation, including optical diagnosis, classification, and staging of LSTs; 14 statements on endoscopic resection indications and technique, including statements on en bloc and piecemeal resection decision-making; seven statements on postresection evaluation; and eight statements on postresection care. CONCLUSIONS: An international expert consensus based on the current available evidence has been developed to guide the evaluation, resection, and follow-up of LSTs. This may provide guiding principles for the global management of these lesions and standardize current practices.

The Surface Morphology of Large Nonpedunculated Colonic Polyps Predicts Synchronous Large Lesions.

BACKGROUND & AIMS: Large (≥20 mm) nonpedunculated colorectal polyps (LNPCPs) may have synchronous LNPCPs in up to 18% of cases. The nature of this relationship has not been investigated. We aimed to examine the relationship between individual LNPCP characteristics and synchronous colonic LNPCPs. METHODS: Consecutive patients referred for resection of LNPCPs over 130 months until March 2022 were enrolled. Serrated lesions and mixed granularity LNPCPs were excluded from analysis. Patients with multiple LNPCPs resected were identified, and the largest was labelled as dominant. The primary outcome was the identification of individual lesion characteristics associated with the presence of synchronous LNPCPs. RESULTS: There were 3149 of 3381 patients (93.1%) who had a single LNPCP. In 232 (6.9%) a synchronous lesion was detected. Solitary lesions had a median size of 35 mm with a predominant Paris 0-IIa morphology (42.9%) and right colon location (59.5%). In patients with ≥2 LNPCPs, the dominant lesion had a median size of 40 mm, Paris 0-IIa (47.6%) morphology, and right colon location (65.9%). In this group, 35.8% of dominant LNPCPs were non-granular compared with 18.7% in the solitary LNPCP cohort. Non-granular (NG)-LNPCPs were more likely to demonstrate synchronous disease, with left colon NG-LNPCPs demonstrating greater risk (odds ratio, 4.78; 95% confidence interval, 2.95-7.73) than right colon NG-LNPCPs (odds ratio, 1.99; 95% confidence interval, 1.39-2.86). CONCLUSIONS: We found that 6.9% of LNPCPs have synchronous disease, with NG-LNPCPs demonstrating a greater than 4-fold increased risk. With post-colonoscopy interval cancers exceeding 5%, endoscopists must be cognizant of an individual's LNPCP phenotype when examining the colon at both index procedure and surveillance. CLINICALTRIALS: gov, NCT01368289; NCT02000141; NCT02198729.

Rio de Janeiro Global Consensus on Landmarks, Definitions, and Classifications in Barrett's Esophagus: World Endoscopy Organization Delphi Study.

BACKGROUND & AIMS: Despite the significant advances made in the diagnosis and treatment of Barrett's esophagus (BE), there is still a need for standardized definitions, appropriate recognition of endoscopic landmarks, and consistent use of classification systems. Current controversies in basic definitions of BE and the relative lack of anatomic knowledge are significant barriers to uniform documentation. We aimed to provide consensus-driven recommendations for uniform reporting and global application. METHODS: The World Endoscopy Organization Barrett's Esophagus Committee appointed leaders to develop an evidence-based Delphi study. A working group of 6 members identified and formulated 23 statements, and 30 internationally recognized experts from 18 countries participated in 3 rounds of voting. We defined consensus as agreement by ≥80% of experts for each statement and used the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) tool to assess the quality of evidence and the strength of recommendations. RESULTS: After 3 rounds of voting, experts achieved consensus on 6 endoscopic landmarks (palisade vessels, gastroesophageal junction, squamocolumnar junction, lesion location, extraluminal compressions, and quadrant orientation), 13 definitions (BE, hiatus hernia, squamous islands, columnar islands, Barrett's endoscopic therapy, endoscopic resection, endoscopic ablation, systematic inspection, complete eradication of intestinal metaplasia, complete eradication of dysplasia, residual disease, recurrent disease, and failure of endoscopic therapy), and 4 classification systems (Prague, Los Angeles, Paris, and Barrett's International NBI Group). In round 1, 18 statements (78%) reached consensus, with 12 (67%) receiving strong agreement from more than half of the experts. In round 2, 4 of the remaining statements (80%) reached consensus, with 1 statement receiving strong agreement from 50% of the experts. In the third round, a consensus was reached on the remaining statement. CONCLUSIONS: We developed evidence-based, consensus-driven statements on endoscopic landmarks, definitions, and classifications of BE. These recommendations may facilitate global uniform reporting in BE.

Oncological outcomes after piecemeal endoscopic mucosal resection of large non-pedunculated colorectal polyps with covert submucosal invasive cancer.

OBJECTIVE: Management of covert submucosal invasive cancer (SMIC) discovered after piecemeal endoscopic mucosal resection (pEMR) of large (>20 mm) non-pedunculated colorectal polyps is challenging. The residual cancer risk is largely unknown. We sought to evaluate this in a large tertiary referral cohort. DESIGN: Cases of covert SMIC following pEMR were identified and followed. Oncological outcomes after surgery were divided based on residual intramural cancer, lymph node metastases (LNM) or both. Risk factors for residual intramural cancer and LNM were analysed based on the original pEMR histological variables. Risk parameters were analysed with respect to low and high-risk variables for residual intramural cancer and LNM. RESULTS: Among 3372 cases of large non-pedunculated colorectal polyps, 143 cases of covert SMIC (4.2%) were identified. 109 underwent surgical resection. Histological analysis of pEMR histology was available in 98 of 109 (90%) cases. 62 cases (63%) had no residual malignancy. 36 cases had residual malignancy (residual intramural cancer n=24; LNM n=5; both n=7). All cases of residual intramural cancer could be identified by a R1 histological deep margin. Cases with poor differentiation (PD) and/or lymphovascular invasion (LVI) had a high risk of LNM (12/33), with a very low risk without these criteria (<1%; 0/65). Cases at low risk for LNM with R0 deep margin have a low risk of residual intramural cancer (<1%; 0/35). CONCLUSION: The majority of cases of large non-pedunculated colorectal polyps with covert SMIC following pEMR will have no residual malignancy. The risk of residual malignancy can be ascertained from three key variables: PD, LVI and R1 deep margin.

Outcomes of Deep Mural Injury After Endoscopic Resection: An International Cohort of 3717 Large Non-Pedunculated Colorectal Polyps.

BACKGROUND & AIMS: Although perforation is the most feared adverse event associated with endoscopic mucosal resection (EMR), limited data exists concerning its management. Therefore, we sought to evaluate the short- and long-term outcomes of intra-procedural deep mural injury (DMI) in an international multi-center observational cohort of large (≥20 mm) non-pedunculated colorectal polyps (LNPCPs). METHODS: Consecutive patients who underwent EMR for a LNPCP ≥20 mm were evaluated. Significant DMI (S-DMI) was defined as Sydney DMI Classification type III (muscularis propria injury, target sign) or type IV/V (perforation without or with contamination, respectively). The primary outcome was successful S-DMI defect closure. Secondary outcomes included technical success (removal of all visible polypoid tissue during index EMR), surgical referral and recurrence at first surveillance colonscopy (SC1). RESULTS: Between July 2008 to May 2020, 3717 LNPCPs underwent EMR. Median lesion size was 35mm (interquartile range (IQR) 25 to 45mm). Significant DMI was identified in 101 cases (2.7%), with successful defect closure in 98 (97.0%) using a median of 4 through-the-scope clips (TTSCs; IQR 3 to 6 TTSCs). Three (3.0%) patients underwent S-DMI-related urgent surgery. Technical success was achieved in 94 (93.1%) patients, with 46 (45.5%) admitted to hospital (median duration 1 day; IQR 1 to 2 days). Comparing LNPCPs with and without S-DMI, no differences in technical success (94 (93.1%) vs 3316 (91.7%); P = .62) or SC1 recurrence (12 (20.0%) vs 363 (13.6%); P = .15) were identified. CONCLUSIONS: Significant DMI is readily managed endoscopically and does not appear to affect technical success or recurrence.

Global variations in diagnostic guidelines for Barrett's esophagus.

Endoscopic diagnosis of gastroesophageal junction and Barrett's esophagus is essential for surveillance and early detection of esophageal adenocarcinoma and esophagogastric junction cancer. Despite its small size, the gastroesophageal junction has many inherent problems, including marked differences in diagnostic methods for Barrett's esophagus in international guidelines. To define Barrett's esophagus, gastroesophageal junction location should be clarified. Although gastric folds and palisade vessels are landmarks for identifying this junction, they are sometimes difficult to observe due to air entry or reflux esophagitis. The possibility of diagnosing a malignancy associated with Barrett's esophagus <1 cm, identified using palisade vessels, should be re-examined. Nontargeted biopsies of Barrett's esophagus are commonly used to detect intestinal metaplasia, dysplasia, and cancer as described in the Seattle protocol. Barrett's esophagus with intestinal metaplasia has a high risk of becoming cancerous. Furthermore, the frequency of cancer in patients with Barrett's esophagus without intestinal metaplasia is high, and the guidelines differ on whether to include the presence of intestinal metaplasia in the diagnosis of Barrett's esophagus. Use of advanced imaging technologies, including narrow-band imaging with magnifying endoscopy and linked color imaging, is reportedly valid for diagnosing Barrett's esophagus. Furthermore, artificial intelligence has facilitated the diagnosis of Barrett's esophagus through its deep learning and image recognition capabilities. However, it is necessary to first use the endoscopic definition of the gastroesophageal junction, which is common in all countries, and then elucidate the characteristics of Barrett's esophagus in each region, for example, length differences in the risk of carcinogenesis with and without intestinal metaplasia.

Optical Evaluation for Predicting Cancer in Large Nonpedunculated Colorectal Polyps Is Accurate for Flat Lesions.

BACKGROUND AND AIMS: The ability of optical evaluation to diagnose submucosal invasive cancer (SMIC) prior to endoscopic resection of large (≥20 mm) nonpedunculated colorectal polyps (LNPCPs) is critical to inform therapeutic decisions. Prior studies suggest that it is insufficiently accurate to detect SMIC. It is unknown whether lesion morphology influences optical evaluation performance. METHODS: LNPCPs ≥20 mm referred for endoscopic resection within a prospective, multicenter, observational cohort were evaluated. Optical evaluation was performed prior to endoscopic resection with the optical prediction of SMIC based on established features (Kudo V pit pattern, depressed morphology, rigidity/fixation, ulceration). Optical evaluation performance outcomes were calculated. Outcomes were reported by dominant morphology: nodular (Paris 0-Is/0-IIa+Is) vs flat (Paris 0-IIa/0-IIb) morphology. RESULTS: From July 2013 to July 2019, 1583 LNPCPs (median size 35 [interquartile range, 25-50] mm; 855 flat, 728 nodular) were assessed. SMIC was identified in 146 (9.2%; 95% confidence interval [CI], 7.9%-10.8%). Overall sensitivity and specificity were 67.1% (95% CI, 59.2%-74.2%) and 95.1% (95% CI, 93.9%-96.1%), respectively. The overall SMIC miss rate was 3.0% (95% CI, 2.3%-4.0%). Significant differences in sensitivity (90.9% vs 52.7%), specificity (96.3% vs 93.7%), and SMIC miss rate (0.6% vs 5.9%) between flat and nodular LNPCPs were identified (all P < .027). Multiple logistic regression identified size ≥40 mm (odds ratio [OR], 2.0; 95% CI, 1.0-3.8), rectosigmoid location (OR, 2.0; 95% CI, 1.1-3.7), and nodular morphology (OR, 7.2; 95% CI, 2.8-18.9) as predictors of missed SMIC (all P < .039). CONCLUSIONS: Optical evaluation performance is dependent on lesion morphology. In the absence of features suggestive of SMIC, flat lesions can be presumed benign and be managed accordingly.

Effects of coronavirus disease 2019 on the digestive system and its nutritional implications.

PURPOSE OF REVIEW: There has been a deluge of scientific data since coronavirus disease 2019 (COVID-19) was first reported. The effects of COVID-19 on the digestive system are now increasingly well understood. This article aims to review the current data on the effects of COVID-19 on the digestive system with particular emphasis on preexisting digestive diseases and its implications on nutrition practices. RECENT FINDINGS: Evidence has shown that Severe acute respiratory syndrome coronavirus 2 virus affects the gastrointestinal (GI) tract, pancreas and hepatobiliary system resulting in different GI manifestations. Several preexisting digestive diseases have been investigated. These studies have revealed that these special patient population groups are generally not at an increased risk to contract COVID-19, but are susceptible to develop increasing severity of disease. Aside from medical therapy, optimizing nutritional care has a beneficial role in this group of patients. SUMMARY: GI manifestations of COVID-19 in addition to preexisting digestive diseases have an impact on patient's nutrition. Digestion, absorption and transport of nutrients may be impaired. To date, there are no existing guidelines on the nutritional management of patients for this particular at-risk group. Most nutrition practices are based only on observations and clinical experience. Basic prepandemic nutrition care principles are primarily followed but often individualized based on clinical judgment.

Barrett's esophagus with low-grade dysplasia: high rate of upstaging at Barrett's esophagus referral units suggests progression rates may be overestimated.

BACKGROUND AND AIMS: The reported progression rate from low-grade dysplasia (LGD) in Barrett's esophagus (BE) to high-grade dysplasia (HGD) or esophageal adenocarcinoma (EAC) ranges from .4% to 13.4% per year. We hypothesize that some reported progression rates may be overestimated because of prevalent HGD or EAC that was not identified during endoscopic assessments performed in the community. Our aim is to determine the proportion of prevalent HGD or EAC detected by BE referral units (BERUs) in patients referred from the community with a recent diagnosis of LGD. METHODS: All patients referred from the community to 6 BERUs with a diagnosis of BE with LGD were identified. Patients with an assessment endoscopy performed at BERUs more than 6 months from their referral endoscopy in the community were excluded. Visible lesions and histology outcomes were compared between the community referral endoscopy and the assessment endoscopy performed at BERUs. RESULTS: The median time between BERU assessment and referral endoscopy was 79 days (interquartile range, 54-114). Of the 75 patients referred from the community with LGD, BERU assessment identified HGD or EAC in 20 patients (27%). BERU assessment identified more visible lesions than referral endoscopy performed in the community (39 [52%] vs 9 [12%], respectively; P = .029). CONCLUSIONS: BERU assessment endoscopy identified more visible lesions than community referral endoscopy and identified HGD or EAC in 27% of patients referred from the community with a recent diagnosis of LGD. Reported progression rates from LGD to HGD or EAC may be overestimated.

Establishing key research questions for the implementation of artificial intelligence in colonoscopy: a modified Delphi method.

BACKGROUND : Artificial intelligence (AI) research in colonoscopy is progressing rapidly but widespread clinical implementation is not yet a reality. We aimed to identify the top implementation research priorities. METHODS : An established modified Delphi approach for research priority setting was used. Fifteen international experts, including endoscopists and translational computer scientists/engineers, from nine countries participated in an online survey over 9 months. Questions related to AI implementation in colonoscopy were generated as a long-list in the first round, and then scored in two subsequent rounds to identify the top 10 research questions. RESULTS : The top 10 ranked questions were categorized into five themes. Theme 1: clinical trial design/end points (4 questions), related to optimum trial designs for polyp detection and characterization, determining the optimal end points for evaluation of AI, and demonstrating impact on interval cancer rates. Theme 2: technological developments (3 questions), including improving detection of more challenging and advanced lesions, reduction of false-positive rates, and minimizing latency. Theme 3: clinical adoption/integration (1 question), concerning the effective combination of detection and characterization into one workflow. Theme 4: data access/annotation (1 question), concerning more efficient or automated data annotation methods to reduce the burden on human experts. Theme 5: regulatory approval (1 question), related to making regulatory approval processes more efficient. CONCLUSIONS : This is the first reported international research priority setting exercise for AI in colonoscopy. The study findings should be used as a framework to guide future research with key stakeholders to accelerate the clinical implementation of AI in endoscopy.

Artificial intelligence in upper GI endoscopy - current status, challenges and future promise.

White-light endoscopy with biopsy is the current gold standard modality for detecting and diagnosing upper gastrointestinal (GI) pathology. However, missed lesions remain a challenge. To overcome interobserver variability and learning curve issues, artificial intelligence (AI) has recently been introduced to assist endoscopists in the detection and diagnosis of upper GI neoplasia. In contrast to AI in colonoscopy, current AI studies for upper GI endoscopy are smaller pilot studies. Researchers currently lack large volume, well-annotated, high-quality datasets in gastric cancer, dysplasia in Barrett's esophagus and early esophageal squamous cell cancer. This review will look at the latest studies of AI in upper GI endoscopy, discuss some of the challenges facing researchers, and predict what the future may hold in this rapidly changing field.

Diagnostic accuracy of narrow-band imaging endoscopy with targeted biopsies compared with standard endoscopy with random biopsies in patients with Barrett's esophagus: A systematic review and meta-analysis.

BACKGROUND AND AIM: Endoscopic surveillance for dysplasia in Barrett's esophagus (BE) with random biopsies is the primary diagnostic tool for monitoring clinical progression into esophageal adenocarcinoma. As an alternative, narrow-band imaging (NBI) endoscopy offers targeted biopsies that can improve dysplasia detection. This study aimed to evaluate NBI-guided targeted biopsies' diagnostic accuracy for detecting dysplasia in patients undergoing endoscopic BE surveillance compared with the widely used Seattle protocol. METHODS: Cochrane DTA Register, MEDLINE/PubMed, EMBASE, OpenGrey, and bibliographies of identified papers were searched until 2018. Two independent investigators resolved discrepancies by consensus, study selection, data extraction, and quality assessment. Data on sensitivity, specificity, and predictive values were pooled and analyzed using a random-effects model. RESULTS: Of 9528 identified articles, six studies comprising 493 participants were eligible for quantitative synthesis. NBI-targeted biopsy showed high diagnostic accuracy in detection of dysplasia in BE with a sensitivity of 76% (95% confidence interval [CI]: 0.61-0.91), specificity of 99% (95% CI: 0.99-1.00), positive predictive value of 97% (95% CI: 0.96-0.99), and negative predictive value of 84% (95% CI: 0.69-0.99) for detection of all grades of dysplasia. The receiver-operating characteristic curve for NBI model performance was 0.8550 for detecting all dysplasia. CONCLUSION: Narrow-band imaging-guided biopsy demonstrated high diagnostic accuracy and might constitute a valid substitute for random biopsies during endoscopic surveillance for dysplasia in BE.

Thermal Ablation of Mucosal Defect Margins Reduces Adenoma Recurrence After Colonic Endoscopic Mucosal Resection.

BACKGROUND & AIMS: Colorectal cancer (CRC) can be prevented by colonoscopy and polypectomy. Endoscopic mucosal resection (EMR) is performed to remove large laterally spreading colonic lesions that have a high risk of progression to CRC. Endoscopically invisible micro-adenomas at the margins of the EMR site might contribute to adenoma recurrence, which occurs in 15% to 30% of patients who undergo surveillance. We aimed to determine the efficacy of adjuvant thermal ablation of the EMR mucosal defect margin in reducing polyp recurrence. METHODS: We performed a prospective study of 390 patients with large laterally spreading colonic lesions (≥ 20 mm, n = 416) referred for EMR at 4 tertiary centers in Australia. After complete lesion excision by EMR, lesions were randomly assigned to thermal ablation of the post-EMR mucosal defect margin (n = 210) or no additional treatment (controls, n = 206). We performed surveillance colonoscopies with standardized photo documentation and biopsies of the scar after 5 to 6 months. Patient, procedure, and lesion characteristics were similar between the groups. The primary endpoint was detection of lesion recurrence at first surveillance colonoscopy. RESULTS: A significantly lower proportion of patients who received thermal ablation of the post-EMR mucosal defect margin had evidence of recurrence at first surveillance colonoscopy (10/192, 5.2%) than controls (37/176, 21.0%) (P < .001). The relative risk of recurrence in the thermal ablation group was 0.25 compared with the control group (95% confidence interval 0.13-0.48). Rates of adverse events were similar between the groups. CONCLUSIONS: In a multicenter randomized trial, thermal ablation of the post-EMR mucosal defect margin significantly reduced polyp recurrence at first surveillance colonoscopy, compared with no additional treatment. Routine implementation of this simple and safe technique could increase the utility of EMR, decrease surveillance burdens, and reduce morbidity and mortality from CRC. ClinicalTrials.gov no: NCT01789749.

Computer-aided diagnosis for characterization of colorectal lesions: comprehensive software that includes differentiation of serrated lesions.

BACKGROUND AND AIMS: Endoscopy guidelines recommend adhering to policies such as resect and discard only if the optical biopsy is accurate. However, accuracy in predicting histology can vary greatly. Computer-aided diagnosis (CAD) for characterization of colorectal lesions may help with this issue. In this study, CAD software developed at the University of Adelaide (Australia) that includes serrated polyp differentiation was validated with Japanese images on narrow-band imaging (NBI) and blue-laser imaging (BLI). METHODS: CAD software developed using machine learning and densely connected convolutional neural networks was modeled with NBI colorectal lesion images (Olympus 190 series - Australia) and validated for NBI (Olympus 290 series) and BLI (Fujifilm 700 series) with Japanese datasets. All images were correlated with histology according to the modified Sano classification. The CAD software was trained with Australian NBI images and tested with separate sets of images from Australia (NBI) and Japan (NBI and BLI). RESULTS: An Australian dataset of 1235 polyp images was used as training, testing, and internal validation sets. A Japanese dataset of 20 polyp images on NBI and 49 polyp images on BLI was used as external validation sets. The CAD software had a mean area under the curve (AUC) of 94.3% for the internal set and 84.5% and 90.3% for the external sets (NBI and BLI, respectively). CONCLUSIONS: The CAD achieved AUCs comparable with experts and similar results with NBI and BLI. Accurate CAD prediction was achievable, even when the predicted endoscopy imaging technology was not part of the training set.

Narrow-band imaging for scar (NBI-SCAR) classification: from conception to multicenter validation.

BACKGROUND AND AIMS: Surveillance post-endoscopic resection (ER) currently warrants biopsy samples from the resection site scar in most cases, although clinical practice is variable. A classification with standard criteria for scars has not yet been established. We aimed to create and validate a novel classification for post-ER scars by using specific criteria based on advanced imaging. METHODS: Key endoscopic features for scars with and without recurrence were (1) dark brown color, elongated/branched pit pattern, and dense capillary pattern and (2) whitish, pale appearance, round/slightly large pits, and irregular sparse vessels. Scars were first assessed with high-definition white-light endoscopy (HD-WLE) followed by interrogation with narrow-band imaging (NBI). Scars with at least 2 concordant characteristics were diagnosed with "high confidence" for NBI for scar (NBI-SCAR) classification. The final endoscopic predictions were correlated with histopathology. The primary outcome was the difference in sensitivity between NBI-SCAR and HD-WLE predictions. Secondary outcomes included the validation of our findings in 6 different endoscopy settings (Australia, United States, Japan, Brazil, Singapore, and Malaysia). The validation took place in 2 sessions separated by 2 to 3 weeks, each with 10 one-minute videos of post-ER scars on underwater NBI with dual focus. Inter-rater and intrarater reliability were calculated with Fleiss' free-marginal kappa and Bennett et al. S score, respectively. RESULTS: One hundred scars from 82 patients were included. Ninety-five scars were accurately predicted with high confidence by NBI-SCAR in the exploratory phase. NBI-SCAR sensitivity was significantly higher compared with HD-WLE (100% vs 73.7%, P < .05). In the validation phase, similar results were found for endoscopists who routinely perform colonoscopies and use NBI (sensitivity of 96.4%). The inter-rater and intrarater reliability throughout all centers were, respectively, substantial (κ = .61) and moderate (average S = .52) for this subset. CONCLUSIONS: NBI-SCAR has a high sensitivity and negative predictive value for excluding recurrence for endoscopists experienced in colonoscopy and NBI. In this setting, this approach may help to accurately evaluate or resect scars and potentially mitigate the burden of unnecessary biopsy samples.

Impact of en bloc resection on long-term outcomes after endoscopic mucosal resection: a matched cohort study.

BACKGROUND AND AIMS: Residual or recurrent adenoma (RRA) is the major limitation of piecemeal EMR (p-EMR) for large colonic laterally spreading lesions (LSLs) ≥20 mm. En bloc EMR (e-EMR) has been shown to achieve low rates of RRA but specific procedural and long-term outcomes are unknown. Our aim was to compare long-term outcomes of size-matched LSLs stratified by whether they were resected e-EMR or p-EMR. METHODS: Data from a prospective tertiary referral multicenter cohort of large LSLs referred for EMR over a 10-year period were analyzed. Outcomes were compared between sized-matched LSLs (20-25 mm) resected by p-EMR or e-EMR. RESULTS: Five hundred seventy LSLs met the inclusion criteria of which 259 (45.4%) were resected by e-EMR. The risk of major deep mural injury (DMI) was significantly higher in the e-EMR group (3.5% vs 1.0%, P = .05), whereas rates of other intraprocedural adverse events did not differ significantly. Five of 9 (56%) LSLs, with endoscopic features of submucosal invasion (SMI), resected by e-EMR were saved from surgery. RRA at first surveillance was lower in the e-EMR group (2.0% vs 5.7%, P = .04), but this difference was negated at subsequent surveillance. Rates of surgical referral were not significantly different between the groups at either surveillance interval. CONCLUSION: When comparing e-EMR against p-EMR for lesions ≤25 mm in size of similar morphology in a large prospective multicenter cohort, e-EMR offered no additional advantage for predicted-benign LSLs. However, it was associated with an increased risk of major DMI. Thus, en bloc resection techniques should be reserved for lesions suspicious for invasive disease. (Clinical trial registration number: NCT01368289.).