Search

Detection and diagnosis of colon polyps are key to preventing colorectal cancer. Recent evidence suggests that AI-based computer-aided detection (CADe) and computer-aided diagnosis (CADx) systems can enhance endoscopists' performance and boost colonoscopy effectiveness. However, most available public datasets primarily consist of still images or video clips, often at a down-sampled resolution, and do not accurately represent real-world colonoscopy procedures. We introduce the REAL-Colon (Real-world multi-center Endoscopy Annotated video Library) dataset: a compilation of 2.7 M native video frames from sixty full-resolution, real-world colonoscopy recordings across multiple centers. The dataset contains 350k bounding-box annotations, each created under the supervision of expert gastroenterologists. Comprehensive patient clinical data, colonoscopy acquisition information, and polyp histopathological information are also included in each video. With its unprecedented size, quality, and heterogeneity, the REAL-Colon dataset is a unique resource for researchers and developers aiming to advance AI research in colonoscopy. Its openness and transparency facilitate rigorous and reproducible research, fostering the development and benchmarking of more accurate and reliable colonoscopy-related algorithms and models., (© 2024. The Author(s).)

Introduction: Sessile serrated lesions (SSLs) have malignant potential for colorectal cancer in the serrated pathway. Selective endoscopic resection of SSLs would reduce medical costs and procedure-related accidents, but the accurate endoscopic differentiation of SSLs from hyperplastic polyps (HPs) is challenging. To explore the differential diagnostic performance of magnifying colonoscopy in distinguishing SSLs from HPs, we conducted a multicenter prospective validation study in clinical practice., Methods: Considering the rarity of diminutive SSLs, all lesions ≥6 mm that were detected during colonoscopy and diagnosed as type 1 based on the Japan narrow-band imaging expert team (JNET) classification were included in this study. Twenty expert endoscopists were asked to differentiate between SSLs and HPs with high or low confidence level after conventional and magnifying NBI observation. To examine the validity of selective endoscopic resection of SSLs using magnifying colonoscopy in clinical practice, we calculated the sensitivity of endoscopic diagnosis of SSLs with histopathological findings as comparable reference., Results: A total of 217 JNET type 1 lesions from 162 patients were analyzed, and 114 lesions were diagnosed with high confidence. The sensitivity of magnifying colonoscopy in detecting SSLs was 79.8% (95% confidence interval [CI]: 74.7-84.4%) overall, and 82.4% (95% CI: 76.1-87.7%) in the high-confidence group. These results showed that the sensitivity of this study was not high enough, even limited in the high-confidence group., Conclusions: Accurate differential diagnosis of SSLs and HPs using magnifying colonoscopy was challenging even for experts. JNET type 1 lesions ≥6 mm are recommended to be resected because selective endoscopic resection has a disadvantage of leaving approximately 20% of SSLs on site., (© 2023 The Author(s). Published by S. Karger AG, Basel.)

Background and Aim: Accurate polyp size estimation is essential in deciding the therapeutic strategy of colorectal polyps and endoscopic surveillance intervals. However, many endoscopists frequently make incorrect size estimations without being aware of their errors. This cross-sectional study aimed to clarify the characteristics of endoscopists associated with inaccurate estimation., Methods: We previously conducted a web trial involving 261 endoscopists in 51 institutions in Japan to assess their ability to estimate polyp size. Participants answered questions about polyp size using visual estimates in a test involving images of 30 polyps. Here, we investigated the relationships between inaccurate size estimation and the backgrounds of participants. The rates of overestimation and underestimation of polyp size were also compared to clarify any trends in the answers of participants with low accuracy (< 50%)., Results: Multivariable logistic regression analysis revealed that the number of colonoscopic procedures in the past year was the only factor associated with a low accuracy of polyp size estimation (odds ratio 0.750, 95% confidence interval 0.609-0.925; P = 0.007). Endoscopists with low accuracy had a greater tendency to overestimate polyp size (42.3% overestimation and 21.2% underestimation, P < 0.001) compared with other endoscopists (16.6% overestimation and 17.9% underestimation, P = 0.951)., Conclusions: Endoscopists with limited experience of colonoscopy in the past year were more likely to make frequent errors in size estimation. Furthermore, endoscopists making inaccurate size estimations had a propensity to overestimate polyp size., (© 2021 Journal of Gastroenterology and Hepatology Foundation and John Wiley & Sons Australia, Ltd.)

Background and Aim: Accurate polyp size estimation is necessary for appropriate management of colorectal polyps. Polyp size is often determined by subjective visual estimation in clinical situations; however, it is inaccurate, especially for beginner endoscopists. We aimed to clarify the usefulness of our short training video, available on the Internet, for accurate polyp size estimation., Methods: We conducted a multicenter prospective controlled study in Japan. After completing a pretest composed of near and far images of 30 polyps, participants received the educational video lecture (<10 min long). The educational content included the knowledge of strategies based on polyp size and criteria for size estimation including the endoscopic equipment size and videos of polyps in vivo. After one month, the participants undertook a posttest. The primary outcome was a change in the accuracy of polyp size visual estimation between the pretest and posttest in beginners., Results: Participants including 111 beginners, 52 intermediates, and 97 experts from 51 institutions completed both tests. Accuracy of polyp size estimation in the beginners showed a significant increase after the video lecture [54.1% (51.3-57.0%) to 59.0% (56.5-61.5%), P = 0.003]. Multivariable logistic regression analysis showed that the category of beginners and a low score on pretest (P = 0.020 and <0.001, respectively) were the factors that contributed to an increase of ≥10% in the accuracy., Conclusion: Our educational video led to an improvement in polyp size estimation in beginners. Furthermore, this video may be useful for non-beginners with insufficient polyp size estimation accuracy., (© 2020 Japan Gastroenterological Endoscopy Society.)

Background & Aims: The benefits of prophylactic clipping to prevent bleeding after polypectomy are unclear. We conducted an updated meta-analysis of randomized trials to assess the efficacy of clipping in preventing bleeding after polypectomy, overall and according to polyp size and location., Methods: We searched the MEDLINE/PubMed, Embase, and Scopus databases for randomized trials that compared the effects of clipping vs not clipping to prevent bleeding after polypectomy. We performed a random-effects meta-analysis to generate pooled relative risks (RRs) with 95% CIs. Multilevel random-effects metaregression analysis was used to combine data on bleeding after polypectomy and estimate associations between rates of bleeding and polyp characteristics., Results: We analyzed data from 9 trials, comprising 71897 colorectal lesions (22.5% 20 mm or larger; 49.2% with proximal location). Clipping, compared with no clipping, did not significantly reduce the overall risk of postpolypectomy bleeding (2.2% with clipping vs 3.3% with no clipping; RR, 0.69; 95% confidence interval [CI], 0.45-1.08; P = .072). Clipping significantly reduced risk of bleeding after removal of polyps that were 20 mm or larger (4.3% had bleeding after clipping vs 7.6% had bleeding with no clipping; RR, 0.51; 95% CI, 0.33-0.78; P = .020) or that were in a proximal location (3.0% had bleeding after clipping vs 6.2% had bleeding with no clipping; RR, 0.53; 95% CI, 0.35-0.81; P < .001). In multilevel metaregression analysis that adjusted for polyp size and location, prophylactic clipping was significantly associated with reduced risk of bleeding after removal of large proximal polyps (RR, 0.37; 95% CI, 0.22-0.61; P = .021) but not small proximal lesions (RR, 0.88; 95% CI, 0.48-1.62; P = .581)., Conclusions: In a meta-analysis of randomized trials, we found that routine use of prophylactic clipping does not reduce risk of postpolypectomy bleeding overall. However, clipping appeared to reduce bleeding after removal of large (more than 20 mm) proximal lesions., (Copyright © 2020 AGA Institute. Published by Elsevier Inc. All rights reserved.)

In recent years, the serrated neoplasia pathway where serrated polyps arise as a colorectal cancer has gained considerable attention as a new carcinogenic pathway. Colorectal serrated polyps are histopathologically classified into hyperplastic polyps (HPs), sessile serrated lesions, and traditional serrated adenomas; in the serrated neoplasia pathway, the latter two are considered to be premalignant. In western countries, all colorectal polyps, including serrated polyps, apart from diminutive rectosigmoid HPs are removed. However, in Asian countries, the treatment strategy for colorectal serrated polyps has remained unestablished. Therefore, in this review, we described the clinicopathological features of colorectal serrated polyps and proposed to remove HPs and sessile serrated lesions ≥ 6 mm in size, and traditional serrated adenomas of any size., Competing Interests: Conflict-of-interest statement: The authors declare that they have no conflict of interest., (©The Author(s) 2020. Published by Baishideng Publishing Group Inc. All rights reserved.)

Background: Management of anticoagulants for patients undergoing polypectomy is still controversial. Cold snare polypectomy (CSP) is reported to cause less bleeding than hot snare polypectomy (HSP)., Objective: To compare outcomes between continuous administration of anticoagulants (CA) with CSP (CA+CSP) and periprocedural heparin bridging (HB) with HSP (HB+HSP) for subcentimeter colorectal polyps., Design: Multicenter, parallel, noninferiority randomized controlled trial. (University Hospital Medical Information Network Clinical Trials Registry: UMIN000019355)., Setting: 30 Japanese institutions., Patients: Patients receiving anticoagulant therapy (warfarin or direct oral anticoagulants) who had at least 1 nonpedunculated subcentimeter colorectal polyp., Intervention: Patients were randomly assigned to undergo HB+HSP or CA+CSP and followed up 28 days after polypectomy., Measurements: The primary end point was incidence of polypectomy-related major bleeding (based on the incidence of poorly controlled intraprocedural bleeding or postpolypectomy bleeding requiring endoscopic hemostasis). The prespecified inferiority margin was -5% (CA+CSP vs. HB+HSP)., Results: A total of 184 patients were enrolled: 90 in the HB+HSP group, 92 in the CA+CSP group, and 2 who declined to participate after enrollment. The incidence of polypectomy-related major bleeding in the HB+HSP and CA+CSP groups was 12.0% (95% CI, 5.0% to 19.1%) and 4.7% (CI, 0.2% to 9.2%), respectively. The intergroup difference for the primary end point was +7.3% (CI, -1.0% to 15.7%), with a 0.4% lower limit of 2-sided 90% CI, demonstrating the noninferiority of CA+CSP. The mean procedure time for each polyp and the hospitalization period were longer in the HB+HSP than in the CA+CSP group., Limitation: An open-label trial assessing 2 factors (anticoagulation approach and polypectomy procedure type) simultaneously., Conclusion: Patients having CA+CSP for subcentimeter colorectal polyps who were receiving oral anticoagulants did not have an increased incidence of polypectomy-related major bleeding, and procedure time and hospitalization were shorter than in those having HB+HSP., Primary Funding Source: Japanese Gastroenterological Association.

Objective: To investigate the success rate of cold snare polypectomy (CSP) for complete resection of 4-9 mm colorectal adenomatous polyps compared with that of hot snare polypectomy (HSP)., Design: A prospective, multicentre, randomised controlled, parallel, non-inferiority trial conducted in 12 Japanese endoscopy units. Endoscopically diagnosed sessile adenomatous polyps, 4-9 mm in size, were randomly assigned to the CSP or HSP group. After complete removal of the polyp using the allocated technique, biopsy specimens from the resection margin after polypectomy were obtained. The primary endpoint was the complete resection rate, defined as no evidence of adenomatous tissue in the biopsied specimens, among all pathologically confirmed adenomatous polyps., Results: A total of 796 eligible polyps were detected in 538 of 912 patients screened for eligibility between September 2015 and August 2016. The complete resection rate for CSP was 98.2% compared with 97.4% for HSP. The non-inferiority of CSP for complete resection compared with HSP was confirmed by the +0.8% (90% CI -1.0 to 2.7) complete resection rate (non-inferiority p<0.0001). Postoperative bleeding requiring endoscopic haemostasis occurred only in the HSP group (0.5%, 2 of 402 polyps)., Conclusions: The complete resection rate for CSP is not inferior to that for HSP. CSP can be one of the standard techniques for 4-9 mm colorectal polyps. (Study registration: UMIN000018328)., Competing Interests: Competing interests: This study was funded by the Investigator Sponsored Research Program of Boston Scientific. The funder paid for statistical analysis, construction of electronic data collecting system and English proofreading service. However, the funder was not involved in the study design, recruitment, analysis plan or interpretation of data., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Background and Aim: The Japan narrow-band imaging (NBI) Expert Team (JNET) was organized to unify four previous magnifying NBI classifications (the Sano, Hiroshima, Showa, and Jikei classifications). The JNET working group created criteria (referred to as the NBI scale) for evaluation of vessel pattern (VP) and surface pattern (SP). We conducted a multicenter validation study of the NBI scale to develop the JNET classification of colorectal lesions., Methods: Twenty-five expert JNET colonoscopists read 100 still NBI images with and without magnification on the web to evaluate the NBI findings and necessity of the each criterion for the final diagnosis., Results: Surface pattern in magnifying NBI images was necessary for diagnosis of polyps in more than 60% of cases, whereas VP was required in around 90%. Univariate/multivariate analysis of candidate findings in the NBI scale identified three for type 2B (variable caliber of vessels, irregular distribution of vessels, and irregular or obscure surface pattern), and three for type 3 (loose vessel area, interruption of thick vessel, and amorphous areas of surface pattern). Evaluation of the diagnostic performance for these three findings in combination showed that the sensitivity for types 2B and 3 was highest (44.9% and 54.7%, respectively), and that the specificity for type 3 was acceptable (97.4%) when any one of the three findings was evident. We found that the macroscopic type (polypoid or non-polypoid) had a minor influence on the key diagnostic performance for types 2B and 3., Conclusion: Based on the present data, we reached a consensus for developing the JNET classification., (© 2018 Japan Gastroenterological Endoscopy Society.)

Background and Aim: Magnifying chromoendoscopy has been one of the most reliable diagnostic methods for distinguishing neoplastic from non-neoplastic lesions. The aim of this prospective study was to clarify the clinical usefulness of magnifying chromoendoscopy for colorectal polyps initially diagnosed with low confidence (LC) by magnifying narrow-band imaging (NBI)., Methods: Consecutive adult patients who underwent total colonoscopic examination with magnifying NBI between July and December 2016 at Sano Hospital were prospectively recruited. Endoscopists were asked to carry out additional magnifying chromoendoscopy for cases that had been initially diagnosed as Japan NBI Expert Team (JNET) Type 1 or 2A with LC by magnifying NBI. We investigated the diagnostic performance of magnifying NBI for polyps diagnosed as JNET Type 1 or 2A with LC (first phase) and that of subsequent magnifying chromoendoscopy (second phase) in differentiating neoplasia from non-neoplasia., Results: In 50 patients, we analyzed 53 polyps classified as JNET Type 1 or 2A with LC prediction. Accuracy and negative predictive value of magnifying NBI (first phase) were 58.5% (95% CI, 44.1-71.9%) and 66.0% (95% CI, 36.6-77.9%), and those of magnifying chromoendoscopy (second phase) were 66.0% (95% CI, 51.7-78.5%) and 61.1% (95% CI, 43.5-76.9%), respectively., Conclusion: Regardless of the findings of additional chromoendoscopy, all polyps should be resected and submitted for histopathological examination when the confidence level in differentiating adenomatous from hyperplastic polyps by magnifying NBI is low., (© 2018 Japan Gastroenterological Endoscopy Society.)

Purpose: Previous studies have yielded conflicting results on the colonic polyp detection rate with narrow-band imaging (NBI) compared with white-light imaging (WLI). We compared the mean number of colonic polyps detected per patient for NBI versus WLI using a next-generation NBI system (EVIS LUCERA ELITE; Olympus Medical Systems) used with standard-definition (SD) colonoscopy and wide-angle (WA) colonoscopy., Design: this study is a 2 × 2 factorial, prospective, multicenter randomized controlled trial., Setting: this study was conducted at five academic centers in Japan., Interventions: patients were allocated to one of four groups: (1) WLI with SD colonoscopy (H260AZI), (2) NBI with SD colonoscopy (H260AZI), (3) WLI with WA colonoscopy (CF-HQ290), and (4) NBI with WA colonoscopy (CF-HQ290)., Main Outcome: the mean numbers of polyps detected per patient were compared between the four groups: WLI with/without WA colonoscopy and NBI with/without WA colonoscopy., Results: Of the 454 patients recruited, 431 patients were enrolled. The total numbers of polyps detected by WLI with SD, NBI with SD, WLI with WA, and NBI with WA were 164, 176, 188, and 241, respectively. The mean number of polyps detected per patient was significantly higher in the NBI group than in the WLI group (2.01 vs 1.56; P = 0.032). The rate was not higher in the WA group than in the SD group (1.97 vs 1.61; P = 0.089)., Conclusions: Although WA colonoscopy did not improve the polyp detection, next-generation NBI colonoscopy represents a significant improvement in the detection of colonic polyps.