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Background: Sessile serrated lesions (SSLs) are associated with an increased risk of colorectal cancer. Data on the prevalence of SSLs in Asia are limited. We performed this study to estimate the prevalence of SSLs in Asia and to explore endoscopic factors that are associated with SSL detection., Methods: This is a post-hoc analysis of a multicenter randomized controlled trial from four Asian countries/regions that compared adenoma detection rates using linked-color imaging (LCI) and white-light imaging. Colonoscopies were performed in an average-risk population for screening, diagnostic examination, or polyp surveillance. Patients with SSLs were compared against those without SSLs to evaluate for possible predictors of SSL detection using Firth's logistic regression., Results: 2898 participants (mean age 64.5 years) were included in the analysis. The estimated prevalence of SSLs was 4.0% (95%CI 3.4%-4.8%), with no sex or age group differences. On multivariable analysis, use of LCI (adjusted odds ratio [aOR] 1.63, 95%CI 1.10-2.41), experienced endoscopists (aOR 1.94, 95%CI 1.25-3.00), use of transparent cap (aOR 1.75, 95%CI 1.09-2.81), and longer withdrawal time (aOR 1.06, 95%CI 1.03-1.10) were independently associated with SSL detection. Synchronous adenoma detection (aOR 1.89, 95%CI 1.20-2.99) was also predictive of SSL detection., Conclusion: The prevalence of SSLs in Asia is 4.0%. Use of LCI or a transparent cap, greater endoscopist experience, and longer withdrawal time were all associated with increased SSL detection., Competing Interests: S. Suzuki, T.L. Ang, H.-M. Chiu, and C.-Y. Kuo have received lecture fees from Fujifilm Corporation. T. Gotoda has received lecture fees from Fujifilm Corporation and Fujifilm Medical Co. Ltd. N. Yoshida and T. Takezawa have received research grants from Fujifilm Corporation. C.K. Tan, X.H. Koh, L.M. Wang, S. Aniwan, K. Laohavichitra, S. Chirapongsathorn, T. Yamamura, R. Rerknimitr, and H. Ishikawa declare that they have no conflict of interest., (Thieme. All rights reserved.)

Introduction: Computer-aided diagnosis (CADx) of polyp histology could support endoscopists in clinical decision-making. However, this has not been validated in a real-world setting., Methods: We performed a prospective, multicenter study comparing CADx and endoscopist predictions of polyp histology in real-time colonoscopy. Optical diagnosis based on visual inspection of polyps was made by experienced endoscopists. After this, the automated output from the CADx support tool was recorded. All imaged polyps were resected for histological assessment. Primary outcome was difference in diagnostic performance between CADx and endoscopist prediction of polyp histology. Subgroup analysis was performed for polyp size, bowel preparation, difficulty of location of the polyps, and endoscopist experience., Results: A total of 661 eligible polyps were resected in 320 patients aged ≥40 years between March 2021 and July 2022. CADx had an overall accuracy of 71.6% (95% confidence interval [CI] 68.0-75.0), compared with 75.2% (95% CI 71.7-78.4) for endoscopists ( P = 0.023). The sensitivity of CADx for neoplastic polyps was 61.8% (95% CI 56.9-66.5), compared with 70.3% (95% CI 65.7-74.7) for endoscopists ( P < 0.001). The interobserver agreement between CADx and endoscopist predictions of polyp histology was moderate (83.1% agreement, κ 0.661). When there was concordance between CADx and endoscopist predictions, the accuracy increased to 78.1%., Discussion: The overall diagnostic accuracy and sensitivity for neoplastic polyps was higher in experienced endoscopists compared with CADx predictions, with moderate interobserver agreement. Concordance in predictions increased this diagnostic accuracy. Further research is required to improve the performance of CADx and to establish its role in clinical practice., (Copyright © 2023 by The American College of Gastroenterology.)

Colonoscopy with endoscopic resection of detected colonic adenomas interrupts the adenoma-carcinoma sequence and reduces the incidence of colorectal cancer and cancer-related mortality. In the past decade, there have been significant developments in instruments and techniques for endoscopic polypectomy. Guidelines have been formulated by various professional bodies in Europe, Japan and the United States, but some of the recommendations differ between the various bodies. An expert professional workgroup under the auspices of the Academy of Medicine, Singapore, was set up to provide guidance on the endoscopic management of colonic polyps in Singapore. A total of 23 recommendations addressed the following issues: accurate description and diagnostic evaluation of detected polyps; techniques to reduce the risk of post-polypectomy bleeding and delayed perforation; the role of specific endoscopic resection techniques; the histopathological criteria for defining endoscopic cure; and the role of surveillance colonoscopy following curative resection., (Copyright: © Singapore Medical Association.)

Colonoscopy is the reference standard procedure for the prevention and diagnosis of colorectal cancer, which is a leading cause of cancer-related deaths in Singapore. Artificial intelligence systems are automated, objective and reproducible. Artificial intelligence-assisted colonoscopy has recently been introduced into clinical practice as a clinical decision support tool. This review article provides a summary of the current published data and discusses ongoing research and current clinical applications of artificial intelligence-assisted colonoscopy., (Copyright: © Singapore Medical Association.)

Background: During surveillance colonoscopy of patients with long-standing ulcerative colitis [UC], a variety of dysplastic and non-dysplastic lesions are detected. The aim of this study was to address the diagnostic accuracy of endoscopic characterization of endoscopic trimodal imaging [ETMI] and chromoendoscopy [CE]. ETMI includes the combination of autofluorescence imaging [AFI], narrow band imaging [NBI] and white light endoscopy [WLE]., Methods: This is a pre-specified additional analysis of a multi-centre, randomized controlled trial that compared AFI with CE for dysplasia detection in 210 patients with long-standing UC [FIND-UC trial]. In the AFI arm, endoscopists used the ETMI system to record AFI colour, Kudo pit pattern using NBI and WLE for lesion characterization. For AFI, purple colour and ambiguous colour combined with pit pattern type III-V on NBI was considered dysplastic. Kudo pit pattern was described in the CE arm. For pit pattern description using NBI and CE, type III-V was considered dysplastic. Histology was the reference standard., Results: In total, 52 dysplastic and 255 non-dysplastic lesions were detected. Overall sensitivity for real-time prediction of dysplasia was 76.9% (95% confidence interval [CI] 46.2-95.0) for ETMI, and 81.6% [95% CI 65.7-92.3] for CE. Overall negative predictive value [NPV] for ETMI was 96.9% [95% CI 92.0-98.8] and 94.7% [90.2-97.2] for CE., Conclusions: Sensitivity for endoscopic differentiation of dysplastic lesions detected during surveillance of patients with long-standing UC seems limited using ETMI and CE. Future research is warranted as the high NPV indicates that these techniques are valuable for the exclusion of dysplastic lesions [NTR4062].

Aims: Traditional serrated adenomas (TSAs) account for 5% of serrated polyps, and have a villiform architecture, eosinophilic cells with a brush border, and indented, flat-topped luminal serrations. However, some are composed of mucin-filled goblet cells (GCs): mucin-rich TSA (MrTSA). The aim of this study was to determine whether this variant has unique features as compared with classic TSA (cTSA)., Methods and Results: One hundred and fifty-six TSAs were retrieved from the period 2010-2016. Patient demographics, site of polyps and 16 microscopic variables were evaluated. TSAs containing ≥50% GCs were classified as MrTSAs. Ectopic crypt foci (ECFs) were quantified as low (1-10) or high (>10), counted at ×200 magnification, and the average was taken for 10 fields. Twenty-four fulfilled the criteria for MrTSA. In males, MrTSAs (65%) were more prevalent than cTSAs (55%). There was no age difference, and both variants had a predilection for the left colon, although, in the right colon, MrTSAs were more frequent (39%) than cTSAs (10%) (P = 0.012). Adenomatous dysplasia was present in four of 24 MrTSAs (low grade, 3; high grade, 1). The most distinctive features of MrTSAs were: a variable growth pattern [endophytic (9%), mixed (30%), or villiform/exophytic (61%)], and a lower frequency of ECFs (P = 0.001) and more intraepithelial lymphocytes (P < 0.05) than in cTSAs. MrTSAs retain characteristic luminal serrations, at least focally. Inflamed MrTSAs can mimic inflammatory polyps and hamartomatous polyps (when there are >95% GCs)., Conclusions: MrTSA is characterized by >50% GCs, and fewer ECFs than cTSA, but with preservation of archetypal luminal serrations. Awareness of this variant will prevent misdiagnosis, given the association of TSA with the accelerated pathway to colorectal cancer., (© 2017 John Wiley & Sons Ltd.)

Background: Traditional serrated adenoma (TSA) is a very characteristic type of serrated polyp that has a predilection for the left colon. Recent molecular advances have shown two molecular phenotypes of TSA: one associated with BRAF mutations and the other with KRAS mutations. The former is associated with hyperplastic polyps (HPs) and sessile serrated adenomas (SSAs), while the latter is associated with more conventional adenomatous dysplasia., Aims: The association of TSAs with so-called precursor lesions (HPs and SSAs) is not well recognised and the purpose of this study was to explore the coexistent presence of HPs, SSAs and adenomatous polyps within a large cohort of TSAs., Methods: In total 149 TSAs were examined for the presence of HP, SSA and adenomatous polyps., Results: Seen in 83 men and 65 women ranging in age from 32 to 89 years and 127 were left sided with 22 in the right colon. Seventy-eight of the 149 TSAs showed evidence of another polyp (52.34%): 32 were low-grade tubular/tubulovillous adenomas (TAs/TVAs; 41%), 28 were HPs (36%) and 18 were SSAs (23%). Eleven of the 22 right-sided TSAs were associated with a precursor lesion (1 HP and 7 SSA). In addition, five TSAs showed more than one polyp type: TSA with TA/TVA and HP (3); TSA with TA/TVA and SSA (2). The TAs/TVAs were adjacent to the TSA but occurred as a separate discrete polyp, while HPs and SSAs were intermingled with the TSA and present at the base and surface of the lesion., Conclusions: More than 50% of TSAs are associated with a precursor lesion or adjacent TA/TVA. Their recognition is important as this may have surveillance and management ramifications., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.)

Aim: The purpose of this survey was to ascertain reporting habits of pathologists towards sessile serrated adenomas/polyps (SSA/P)., Methods: A questionnaire designed to highlight diagnostic criteria, approach and clinical implications of SSA/P was circulated electronically to 45 pathologists in the UK and North America., Results: Forty-three of 45 pathologists agreed to participate. The vast majority (88%) had a special interest in gastrointestinal (GI) pathology, had great exposure to GI polyps in general with 40% diagnosing SSA/P at least once a week if not more, abnormal architecture was thought by all participants to be histologically diagnostic, and 11% would make the diagnosis if a single diagnostic histological feature was present in one crypt only, while a further 19% would diagnose SSA/P in one crypt if more than one diagnostic feature was present. The vast majority agreed that deeper sections were useful and 88% did not feel proliferation markers were useful. More than one-third did not know whether, or did not feel that, their clinicians were aware of the implications of SSA/P., Conclusions: 98% of pathologists surveyed are aware that SSA/P is a precursor lesion to colorectal cancer, the majority agree on diagnostic criteria, and a significant number feel that there needs to be greater communication and awareness among pathologists and gastroenterologists about SSA/P.

The aim of this 4-year audit was to establish whether sessile serrated polyps/adenomas (SSP/A) were diagnosed in a district general hospital in the UK. The study also explored whether SSP/A in the right colon were misdiagnosed as hyperplastic polyps. A retrospective search of the computer records from 2009 to 2012 inclusive for all lesions diagnosed and coded as SSP/A and/or hyperplastic polyps proximal to the splenic flexure was undertaken. All slides were reviewed and a diagnosis of SSP/A made using the criteria recently suggested by the American College of Gastroenterology. Over the study period, no cases of SSP/A were made. On review of all hyperplastic polyps proximal to the splenic flexure, 13/31 in 2009, 17/40 in 2010, 19/48 in 2011 and 16/48 in 2012 were re-classified as SSP/A. The most likely reason for the under-diagnosis of SSP/A is lack of awareness of the lesion both clinically and by pathologists. Adequate biopsies and deeper sections are important to help make the diagnosis of SSP/A. This study shows that SSP/A are reasonably frequently encountered in non-specialist practice settings and that both clinicians and pathologist in this setting need to be aware of its existence.

Aim: An audit of serrated polyps diagnosed over a 4-year period: 2009 to 2012 was undertaken to ascertain the reporting trends of sessile serrated polyps (SSP)., Methods: All right sided hyperplastic polyps (HP) proximal to the splenic flexure and all polyps designated SSP were retrieved from the study period. Three pathologists blinded to the original diagnosis re-examined the slides. Recent American College of Gastroenterology guidelines for the diagnosis of SSP was utilised., Results: No cases of SSP were diagnosed in 2009. In 2010, 32 right-sided cases were encountered, 83 confirmed in 2011 and 134 confirmed in 2012. The vast majority of these were right-sided. With regards to right-sided HP that were re-classified as SSP the data is as follows: 20 of 66 in 2009 (30%); 58 of 91 in 2010 (64%); 42 of 106 (40%) in 2011 and 69 of 206 in 2012 (33%)., Conclusions: This study has demonstrated an almost exponential increase in the diagnosis of SSP over a 4-year period. In addition, 30 to 64% of right-sided HP were re-classified as SSP over the 4-year period suggesting that greater awareness of the diagnostic criteria for SSP is required. SSP is an important precursor lesion in the serrated pathway of colorectal cancer. Its recognition is important for surveillance and therapeutic strategies.