Natural history of diminutive and small colorectal polyps: a systematic literature review

The impact of extended invitation intervals on stage distribution of screen-detected and interval cancer within the Dutch colorectal cancer screening program

This study investigates the impact of extended invitation intervals on the stage distribution of screen-detected and interval colorectal cancers (CRCs) in the Netherlands' fecal immunochemical test (FIT)-based screening program during the COVID-19 pandemic. Using data from individuals with negative FIT results in 2017-2019 and subsequent screening round in 2019-2021, we examined whether delays of up to 6 months affected CRC stage at diagnosis. We performed multivariate logistic regression to assess the association between invitation intervals and cancer stage. Our analysis found no significant difference in stage distribution for both screen-detected and interval CRCs despite the delays. Specifically, odds ratios for late-stage cancer remained close to 1 across various intervals, indicating minimal impact of extended invitation times. These results suggest that the short-term delays caused by the pandemic did not significantly affect the performance of the CRC screening program. This highlights the program's ability to adapt to temporary disruptions while maintaining effective early cancer detection. Our findings support the notion that such disruptions, when managed appropriately, do not substantially compromise the quality of screening outcomes, reinforcing the resilience and flexibility of CRC screening programs in the face of health crises.

Sociodemographic factors associated with psychosocial consequences of false-positive colorectal cancer screening: a prospective cohort study

OBJECTIVES

Receiving a false positive in colorectal cancer screening is associated with psychosocial consequences, yet the reasons why some people are more affected than others remain unclear. This study examines the association between sociodemographic factors and psychosocial consequences among screening participants with false positives in colorectal cancer screening.

DESIGN

Prospective cohort study.

PARTICIPANTS

1432 screening participants with positive faecal immunochemical test (FIT) screening with a follow-up colonoscopy with either no abnormalities or benign polyps (low or medium-high risk).

OUTCOME MEASURES

We measured psychosocial consequences with the Consequences Of Screening - ColoRectal Cancer (COS-CRC) questionnaire, after the positive FIT but before the follow-up colonoscopy and again 1 year later. Sociodemographic factors were obtained from national registers and included sex, age, urbanicity, educational level, occupational status, income, assets, cohabitation status and Charlson Comorbidity Index. Psychosocial consequences were measured before colonoscopy (baseline) and 1 year after, and sociodemographic factors were assessed at baseline.

RESULTS

We tested 19×2×3=114 associations between the sociodemographic factors and psychosocial consequences within the three groups of false positives and five associations were significant. We found that for participants with medium- and high-risk polyps, experiencing short-term psychosocial consequences was significantly associated with having a university degree compared with secondary school (OR=5.04 (1.38; 18.37), p=0.0142) and being unemployed compared with being employed (OR=5.61 (1.42; 22.14), p=0.0139). For participants with low-risk polyps, long-term consequences were significantly associated with the mid-income quartile (OR=2.32 (1.13; 4.76), p=0.0224) and the highest income quartile (OR=5.47 (1.13; 26.48), p=0.0349) compared with the lowest quartile. For participants with no abnormalities, there was an association between short-term psychosocial consequences and having comorbidities compared with none (OR=2.95 (1.13; 7.71), p=0.0277).

CONCLUSION

This study found few significant associations between psychosocial consequences and sociodemographic factors and with no apparent pattern in these. This suggests no strong evidence that specific sociodemographic groups should be especially vulnerable to experiencing psychosocial consequences after a false-positive result from colorectal cancer screening. Thus, there is currently weak evidence for identifying screening participants at higher risk for psychosocial consequences and developing targeted interventions to reduce psychosocial consequences.

A comparative study benchmarking colon polyp with computer-aided detection (CADe) software

Background and aims

Computer-aided detection software (CADe) has shown promising results in real-time polyp detection, but a limited head-to-head comparison of the available CADe systems has been performed. Moreover, such systems have not been compared to endoscopists using standardized videos. This study aims to compare the performance of three CADe systems in detecting polyps, employing a novel standardized methodology.

Methods

Videos from 300 colonoscopies conducted at Oslo University Hospital were analyzed. Short video clips (20-45 s) presenting normal mucosa or polyps were randomly selected. These videos were then streamed through each CADe system from Medtronic, Olympus, and Augere Medical. Each system featured diverse configurations, resulting in a total of six software settings. Sensitivity and false positivity (FP) were assessed by comparing the CADe systems to both the mean of the systems and pairwise between them. Furthermore, the systems' performance was compared to the performance of five endoscopists.

Results

CADe systems' sensitivity ranged between 84.9% and 98.7%, with statistically significant differences observed between the systems, both in comparison to the mean and to each other. FP rates ranged between 1.2% and 5.6%, also differing statistically significantly between the systems. The CADe systems achieving the highest sensitivity also exhibited the highest FP. Statistically significant differences in the alert delay were observed between different CADe systems and endoscopists.

Conclusions

This study highlights significant differences between commercially available CADe software regarding sensitivity and FP, but a superior performance compared to endoscopists. The software with the highest sensitivity also exhibited the highest FP, highlighting the need for further refinement.

Impact of contrast dye submucosal pre-lifting on cold snare resection of small polyps: an Italian randomized observational trial

BACKGROUND/AIMS

Small polyps are the most frequently detected lesions during colonoscopy, with an incomplete resection rate of 6.8% to 15.9%. This study aimed to improve small polyp cold snare resection radicality using submucosal contrast dye pre-lifting (PL+CSP).

METHODS

This single-center, prospective, randomized controlled trial compared the standard cold snare polypectomy technique (PL-CSP) with PL+CSP to evaluate endoscopic and histological complete resection rates, adverse events, procedural times, and polyp retrieval failure rates.

RESULTS

In 143 patients consecutively enrolled, 186 small polyps were detected and randomly assigned following a 1:1 ratio to the PL-CSP (n=97, 51.6%) and PL+CSP (n=90, 48.4%) techniques. Endoscopic (p=0.97) and histologic (p=0.23) complete resection rates did not differ significantly even in univariate analysis. The intraprocedural bleeding rate was significantly higher in the PL+CSP group as confirmed by the univariate analysis (35.8% vs. 8.3%, p<0.001). The polyps retrieval failure rates were similar (p=0.83). Procedural time was significantly longer for PL+CSP (median time, 75 vs. 45 seconds; p<0.001), without impacting colonoscopy withdrawal time (p=0.215).

CONCLUSIONS

PL+CSP of small polyps did not improve endoscopic and histological complete resection rates and polyp sample retrieval. PL+CSP had higher rates of intraprocedural bleeding and was "time-consuming".

A comprehensive RCT in screening, surveillance, and diagnostic AI-assisted colonoscopies (ACCENDO-Colo study)

BACKGROUND AND AIMS

Adenoma detection rate (ADR) serves as a primary quality metric in colonoscopy. Various computer-aided detection (CADe) tools have emerged, yielding diverse impacts on ADR across different demographic cohorts. This study aims to evaluate a new CADe system in patients undergoing colonoscopy.

METHODS

This is an Italian multicenter randomized control trial (RCT) that included patients aged 40-85 scheduled for screening, surveillance or diagnostic colonoscopy randomly assigned to CADe or standard colonoscopy (SC). Patients with a Boston Bowel Preparation Scale < 2 in any segment were excluded. The primary outcome was ADR in both groups. Secondary outcomes included adenoma per colonoscopy (APC), polyp per colonoscopy (PPC) and sessile serrated lesion detection rate (SSLDR).

RESULTS

1228 patients were enrolled of whom 70 were excluded for inadequate bowel cleansing or missed cecal intubation. Therefore, 1158 subjects (578 CADe vs 580 SC) were included in the final analysis. ADR was significantly higher in CADe than in the control group (50.2 % vs 40.5 %, p = 0.001). CADe also significantly increased PPC and APC (1.64 ± 2.03 vs 1.23 ± 1.72, p < 0.001; 1.16 ± 1.82 vs 0.80 ± 1.46 p < 0.001; respectively). No significant differences were found in SSLDR between CADe and SC (12.1 % vs 11.0 %, p = 0.631).

CONCLUSIONS

The results of this RCT indicate that AI-assisted colonoscopy significantly improved ADR in a non-selected population undergoing colonoscopy without causing any significant delay in procedure time or increasing the detection of nonneoplastic lesions. (Ethical committee approval: NCT05862948).

Efficiency of Real-time Computer-aided Polyp Detection during Surveillance Colonoscopy: A Pilot Study

Objectives

Studies have suggested that computer-aided polyp detection using artificial intelligence improves adenoma identification during colonoscopy. However, its real-world effectiveness remains unclear. Therefore, this study evaluated the usefulness of computer-aided detection during regular surveillance colonoscopy.

Methods

Consecutive patients who underwent surveillance colonoscopy with computer-aided detection between January and March 2023 and had undergone colonoscopy at least twice during the past 3 years were recruited. The clinicopathological findings of lesions identified using computer-aided detection were evaluated. The detection ability was sub-analyzed based on the expertise of the endoscopist and the presence of diminutive adenomas (size ≤5 mm).

Results

A total of 78 patients were included. Computer-aided detection identified 46 adenomas in 28 patients; however, no carcinomas were identified. The mean withdrawal time was 824 ± 353 s, and the mean tumor diameter was 3.3 mm (range, 2-8 mm). The most common gross type was 0-Is (70%), followed by 0-Isp (17%) and 0-IIa (13%). The most common tumor locations were the ascending colon and sigmoid colon (28%), followed by the transverse colon (26%), cecum (7%), descending colon (7%), and rectum (4%). Overall, 34.1% and 38.2% of patients with untreated diminutive adenomas and those with no adenomas, respectively, had newly detected adenomas. Endoscopist expertise did not affect the results.

Conclusions

Computer-aided detection may help identify adenomas during surveillance colonoscopy for patients with untreated diminutive adenomas and those with a history of endoscopic resection.

Use of artificial intelligence improves colonoscopy performance in adenoma detection: a systematic review and meta-analysis

BACKGROUND AND AIMS

Artificial intelligence (AI) is increasingly used to improve adenoma detection during colonoscopy. This meta-analysis aimed to provide an updated evaluation of computer-aided detection (CADe) systems and their impact on key colonoscopy quality indicators.

METHODS

We searched the EMBASE, PubMed, and MEDLINE databases from inception until February 15, 2024, for randomized control trials (RCTs) comparing the performance of CADe systems with routine unassisted colonoscopy in the detection of colorectal adenomas.

RESULTS

Twenty-eight RCTs were selected for inclusion involving 23,861 participants. Random-effects meta-analysis demonstrated a 20% increase in adenoma detection rate (risk ratio [RR], 1.20; 95% confidence interval [CI], 1.14-1.27; P < .01) and 55% decrease in adenoma miss rate (RR, 0.45; 95% CI, 0.37-0.54; P < .01) with AI-assisted colonoscopy. Subgroup analyses involving only expert endoscopists demonstrated a similar effect size (RR, 1.19; 95% CI, 1.11-1.27; P < .001), with similar findings seen in analysis of differing CADe systems and healthcare settings. CADe use also significantly increased adenomas per colonoscopy (weighted mean difference, 0.21; 95% CI, 0.14-0.29; P < .01), primarily because of increased diminutive lesion detection, with no significant difference seen in detection of advanced adenomas. Sessile serrated lesion detection (RR, 1.10; 95% CI, 0.93-1.30; P = .27) and miss rates (RR, 0.44; 95% CI, 0.16-1.19; P = .11) were similar. There was an average 0.15-minute prolongation of withdrawal time with AI-assisted colonoscopy (weighted mean difference, 0.15; 95% CI, 0.04-0.25; P = .01) and a 39% increase in the rate of non-neoplastic resection (RR, 1.39; 95% CI, 1.23-1.57; P < .001).

CONCLUSIONS

AI-assisted colonoscopy significantly improved adenoma detection but not sessile serrated lesion detection irrespective of endoscopist experience, system type, or healthcare setting.

The Impact of Endoscopic Mucosal Resection and Endoscopic Submucosal Dissection on Colonic Polyp Resection and Factors Influencing Recurrence

OBJECTIVE

This study aims to assess the effectiveness of endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) in the endoscopic resection of colonic polyps and investigate the factors influencing polyp recurrence.

METHODS

A total of 174 patients with colorectal polyps admitted to the Gastroenterology Department during the same period were included in this prospective randomized controlled study. The patients were randomly allocated to the EMR group and ESD group (72 cases in each group) using a random number table. The clinical efficacy, quality of life, adverse reactions, and 1-year postoperative recurrence rate were compared between the 2 groups. In addition, factors influencing polyp recurrence were analyzed.

RESULTS

No significant differences were observed between the EMR and ESD groups in terms of clinical efficacy, postoperative quality of life, and postoperative complications. However, the postoperative recurrence rate in the ESD group was significantly lower than that in the EMR group. Multifactorial logistic regression analysis revealed that the number of polyps ≥3, maximum polyp diameter ≥2 cm, and family history of colorectal cancer were independent risk factors for colonic polyp recurrence.

CONCLUSION

ESD and EMR demonstrate similar efficacy and safety in patients with colonic polyps. However, the recurrence rate after ESD is significantly lower than after EMR. Furthermore, multifactorial analysis indicates that a larger polyp diameter, a more significant number of polyps, and a family history of colorectal cancer are independent risk factors for the recurrence of colonic polyps following resection.

Computer-aided diagnosis for the resect-and-discard strategy for colorectal polyps: a systematic review and meta-analysis

BACKGROUND

The resect-and-discard strategy allows endoscopists to replace post-polypectomy pathology with real-time prediction of polyp histology during colonoscopy (optical diagnosis). We aimed to investigate the benefits and harms of implementing computer-aided diagnosis (CADx) for polyp pathology into the resect-and-discard strategy.

METHODS

In this systematic review and meta-analysis, we searched MEDLINE, Embase, and Scopus from database inception to June 5, 2024, without language restrictions, for diagnostic accuracy studies that assessed the performance of real-time CADx systems, compared with histology, for the optical diagnosis of diminutive polyps (≤5 mm) in the entire colon. We synthesised data for three strategies: CADx-alone, CADx-unassisted, and CADx-assisted; when the endoscopist was involved in the optical diagnosis, we synthesised data exclusively from diagnoses for which confidence in the prediction was reported as high. The primary outcomes were the proportion of polyps that would have avoided pathological assessment (ie, the proportion optically diagnosed with high confidence; main benefit) and the proportion of polyps incorrectly predicted due to false positives and false negatives (main harm), directly compared between CADx-assisted and CADx-unassisted strategies. We used DerSimonian and Laird's random-effects model to calculate all outcomes. We used Higgins I2 to assess heterogeneity, the Grading of Recommendations, Assessment, Development, and Evaluation approach to rate certainty, and funnel plots and Egger's test to examine publication bias. This study is registered with PROSPERO, CRD42024508440.

FINDINGS

We found 1019 studies, of which 11 (7400 diminutive polyps, 3769 patients, and 185 endoscopists) were included in the final meta-analysis. Three studies (1817 patients and 4086 polyps [2148 neoplastic and 1938 non-neoplastic]) provided data to directly compare the primary outcome measures between the CADx-unassisted and CADx-assisted strategies. We found no significant difference between the CADx-assisted and CADx-unassisted strategies for the proportion of polyps that would have avoided pathological assessment (90% [88-93], 3653 [89·4%] of 4086 polyps diagnosed with high confidence vs 90% [95% CI 85-94], 3588 [87·8%] of 4086 polyps diagnosed with high confidence; risk ratio 1·01 [95% CI 0·99-1·04; I2=53·49%; low-certainty evidence; Egger's test p=0·18). The proportion of incorrectly predicted polyps was lower with the CADx-assisted strategy than with the CADx-unassisted strategy (12% [95% CI 7-17], 523 [14·3%] of 3653 polyps incorrectly predicted with a CADx-assisted strategy vs 13% [6-20], 582 [16·2%] of 3588 polyps incorrectly diagnosed with a CADx-unassisted strategy; risk ratio 0·88 [95% CI 0·79-0·98]; I2=0·00%; low-certainty evidence; Egger's test p=0·18).

INTERPRETATION

CADx did not produce benefit nor harm for the resect-and-discard strategy, questioning its value in clinical practice. Improving the accuracy and explainability of CADx is desired.

FUNDING

European Commission (Horizon Europe), the Japan Society of Promotion of Science, and Associazione Italiana per la Ricerca sul Cancro.

International Digestive Endoscopy Network Consensus on the Management of Antithrombotic Agents in Patients Undergoing Gastrointestinal Endoscopy

Antithrombotic agents, including antiplatelet agents and anticoagulants, are widely used in Korea because of the increasing incidence of cardiocerebrovascular disease and the aging population. The management of patients using antithrombotic agents during endoscopic procedures is an important clinical challenge. The clinical practice guidelines for this issue, developed by the Korean Society of Gastrointestinal Endoscopy, were published in 2020. However, new evidence on the use of dual antiplatelet therapy and direct anticoagulant management has emerged, and revised guidelines have been issued in the United States and Europe. Accordingly, the previous guidelines were revised. Cardiologists were part of the group that developed the guideline, and the recommendations went through a consensus-reaching process among international experts. This guideline presents 14 recommendations made based on the Grading of Recommendations, Assessment, Development, and Evaluation methodology and was reviewed by multidisciplinary experts. These guidelines provide useful information that can assist endoscopists in the management of patients receiving antithrombotic agents who require diagnostic and elective therapeutic endoscopy. It will be revised as necessary to cover changes in technology, evidence, or other aspects of clinical practice.

Autonomous Artificial Intelligence vs Artificial Intelligence-Assisted Human Optical Diagnosis of Colorectal Polyps: A Randomized Controlled Trial

BACKGROUND & AIMS

Artificial intelligence (AI)-based optical diagnosis systems (CADx) have been developed to allow pathology prediction of colorectal polyps during colonoscopies. However, CADx systems have not yet been validated for autonomous performance. Therefore, we conducted a trial comparing autonomous AI to AI-assisted human (AI-H) optical diagnosis.

METHODS

We performed a randomized noninferiority trial of patients undergoing elective colonoscopies at 1 academic institution. Patients were randomized into (1) autonomous AI-based CADx optical diagnosis of diminutive polyps without human input or (2) diagnosis by endoscopists who performed optical diagnosis of diminutive polyps after seeing the real-time CADx diagnosis. The primary outcome was accuracy in optical diagnosis in both arms using pathology as the gold standard. Secondary outcomes included agreement with pathology for surveillance intervals.

RESULTS

A total of 467 patients were randomized (238 patients/158 polyps in the autonomous AI group and 229 patients/179 polyps in the AI-H group). Accuracy for optical diagnosis was 77.2% (95% confidence interval [CI], 69.7-84.7) in the autonomous AI group and 72.1% (95% CI, 65.5-78.6) in the AI-H group (P = .86). For high-confidence diagnoses, accuracy for optical diagnosis was 77.2% (95% CI, 69.7-84.7) in the autonomous AI group and 75.5% (95% CI, 67.9-82.0) in the AI-H group. Autonomous AI had statistically significantly higher agreement with pathology-based surveillance intervals compared to AI-H (91.5% [95% CI, 86.9-96.1] vs 82.1% [95% CI, 76.5-87.7]; P = .016).

CONCLUSIONS

Autonomous AI-based optical diagnosis exhibits noninferior accuracy to endoscopist-based diagnosis. Both autonomous AI and AI-H exhibited relatively low accuracy for optical diagnosis; however, autonomous AI achieved higher agreement with pathology-based surveillance intervals. (ClinicalTrials.gov, Number NCT05236790).

[IDEN Consensus on Management of Antithrombotic Agents in Patients Undergoing Gastrointestinal Endoscopy]

Antithrombotic agents, including antiplatelet agent and anticoagulants are widely used in Korea due to increasing incidence of cardio-cerebrovascular disease and aging population. The management of patients using antithrombotic agents during endoscopic procedures is an important clinical challenge. Clinical practice guideline regarding this issue which was developed by the Korean Society of Gastrointestinal Endoscopy was published in 2020. However, since then, new evidence has emerged for the use of dual antiplatelet therapy and direct anticoagulant management, and revised guidelines were issued in the US and Europe. Accordingly, the previous guidelines were revised, cardiologists also participated in the development group, and the recommendations went through a consensus process among international experts. This guideline presents 14 recommendations made according to the Grading of Recommendations, Assessment, Development, and Evaluation methodology, and was reviewed by multidisciplinary experts. This guideline provides useful information that can assist endoscopists in the management of patients on antithrombotic agents who require diagnostic and elective therapeutic endoscopy. It will be revised as necessary to cover changes in technology, evidence, or other aspects of clinical practice.

Improvement of adenoma detection rate by two computer-aided colonic polyp detection systems in high adenoma detectors: a randomized multicenter trial

BACKGROUND

This study aimed to evaluate the benefits of a self-developed computer-aided polyp detection system (SD-CADe) and a commercial system (CM-CADe) for high adenoma detectors compared with white-light endoscopy (WLE) as a control.

METHODS

Average-risk 50-75-year-old individuals who underwent screening colonoscopy at five referral centers were randomized to SD-CADe, CM-CADe, or WLE groups (1:1:1 ratio). Trainees and staff with an adenoma detection rate (ADR) of ≥35% were recruited. The primary outcome was ADR. Secondary outcomes were the proximal adenoma detection rate (pADR), advanced adenoma detection rate (AADR), and the number of adenomas, proximal adenomas, and advanced adenomas per colonoscopy (APC, pAPC, and AAPC, respectively).

RESULTS

The study enrolled 1200 participants. The ADR in the control, CM-CADe, and SD-CADe groups was 38.3%, 50.0%, and 54.8%, respectively. The pADR was 23.0%, 32.3%, and 38.8%, respectively. AADR was 6.0%, 10.3%, and 9.5%, respectively. After adjustment, the ADR and pADR in both intervention groups were significantly higher than in controls (all P<0.05). The APC in the control, CM-CADe, and SD-CADe groups was 0.66, 1.04, and 1.16, respectively. The pAPC was 0.33, 0.53, and 0.64, respectively, and the AAPC was 0.07, 0.12, and 0.10, respectively. Both CADe systems showed significantly higher APC and pAPC than WLE. AADR and AAPC were improved in both CADe groups versus control, although the differences were not statistically significant.

CONCLUSION

Even in high adenoma detectors, CADe significantly improved ADR and APC. The AADR tended to be higher with both systems, and this may enhance colorectal cancer prevention.

International Digestive Endoscopy Network consensus on the management of antithrombotic agents in patients undergoing gastrointestinal endoscopy

Antithrombotic agents, including antiplatelet agents and anticoagulants, are widely used in Korea because of the increasing incidence of cardiocerebrovascular disease and the aging population. The management of patients using antithrombotic agents during endoscopic procedures is an important clinical challenge. The clinical practice guidelines for this issue, developed by the Korean Society of Gastrointestinal Endoscopy, were published in 2020. However, new evidence on the use of dual antiplatelet therapy and direct anticoagulant management has emerged, and revised guidelines have been issued in the United States and Europe. Accordingly, the previous guidelines were revised. Cardiologists were part of the group that developed the guideline, and the recommendations went through a consensus-reaching process among international experts. This guideline presents 14 recommendations made based on the Grading of Recommendations, Assessment, Development, and Evaluation methodology and was reviewed by multidisciplinary experts. These guidelines provide useful information that can assist endoscopists in the management of patients receiving antithrombotic agents who require diagnostic and elective therapeutic endoscopy. It will be revised as necessary to cover changes in technology, evidence, or other aspects of clinical practice.

The absolute number of small and diminutive adenomas with high-grade dysplasia is substantially higher compared with large adenomas: a retrospective pooled study

Introduction

The risk that a large polyp (≥10 mm) evolves into high-grade dysplasia (HGD) is relatively high compared with that of a small/diminutive polyp (<10 mm). Recently, the detection of small and diminutive polyps has been substantially improved with the advancement of endoscopy. However, further research is needed on the role of the incidence of HGD caused by the co-occurrence of small and diminutive polyps in the progression of HGD. In this study, we aim to investigate whether and how the small and diminutive polyps correlate with the incidence of HGD in the population.

Methods

The pooled data were deeply analyzed from four published randomized controlled trials (RCTs) regarding colon polyp detection. All polyps detected were examined and confirmed by pathologists. The primary outcome was the composition ratio of the HGD polyps in each polyp size category.

Results

Among a total of 3,179 patients with 2,730 polyps identified, there were 83 HGD polyps confirmed, and 68 patients had at least one polyp with HGD. The risk of development of HGD was lower for a single small and diminutive polyp than for one large polyp (2.18% vs. 22.22%, P < 0.0001). On the contrary, the composition ratio for HGD from small and diminutive polyps was significantly higher than that from the large ones (68.67% vs. 31.33%, P < 0.0001). The combined number of HGD presented a trend negatively correlated to size.

Conclusions

Our data demonstrated that the absolute number of HGD significantly derives more from small and diminutive polyps than from the large ones, and the collective number of small and diminutive polyps per patient is indicative of his/her HGD exposure. These findings positively provide novel perspectives on the management of polyps and may further optimize the prevention of colorectal cancer.

Systematic Review Registration

http://www.chictr.org.cn, identifier ChiCTR1900025235, ChiCTR1800017675, ChiCTR1800018058, and ChiCTR1900023086.

Endoscopic resection of large anastomotic polyps is safe and effective

BACKGROUND

Large (≥20mm) adenomatous anastomotic polyps (LAAPs) are uncommon. Data pertaining to their prevalence, characteristics, and the efficacy of endoscopic resection (ER) are absent. A safe and effective strategy for ER would reduce morbidity and healthcare costs.

METHODS

Large nonpedunculated colorectal polyps of ≥20mm (LNPCPs) referred for ER were prospectively studied. Multiple data points were recorded including anastomotic location, polyp morphology, resection modality, complications, and technical success.

RESULTS

Over 7 years until November 2022, 2629 lesions were referred. Of these, 10 (0.4%) were LAAPs (median size 35 mm [interquartile range (IQR) 30-40mm]). All LAAPs were removed by piecemeal endoscopic mucosal resection (EMR), most (n=9; 90%) in combination with cold-forceps avulsion with adjuvant snare-tip soft coagulation (CAST). On comparison of the LAAP group with the conventional LNPCP group, CAST was more commonly used (90% vs. 9%; P<0.001) and deep mural injury (DMI) type II was more frequent (40% vs. 11%, P=0.003); however, significant DMI (III-V) did not occur. At 6 month (IQR 5.25-6 months) surveillance, there was no recurrence in any of the 10 cases. There were no serious adverse events.

CONCLUSIONS

LAAPs present unique challenges owing to their location overlying an anastomosis. Despite these challenges they can be safely and effectively managed endoscopically without recurrence at endoscopic follow-up.

Artificial intelligence fails to improve colonoscopy quality: A single centre retrospective cohort study

BACKGROUND

Limited data currently exists on the clinical utility of Artificial Intelligence Assisted Colonoscopy (AIAC) outside of clinical trials.

AIM

To evaluate the impact of AIAC on key markers of colonoscopy quality compared to conventional colonoscopy (CC).

METHODS

This single-centre retrospective observational cohort study included all patients undergoing colonoscopy at a secondary centre in Brisbane, Australia. CC outcomes between October 2021 and October 2022 were compared with AIAC outcomes after the introduction of the Olympus Endo-AID module from October 2022 to January 2023. Endoscopists who conducted over 50 procedures before and after AIAC introduction were included. Procedures for surveillance of inflammatory bowel disease were excluded. Patient demographics, proceduralist specialisation, indication for colonoscopy, and colonoscopy quality metrics were collected. Adenoma detection rate (ADR) and sessile serrated lesion detection rate (SSLDR) were calculated for both AIAC and CC.

RESULTS

The study included 746 AIAC procedures and 2162 CC procedures performed by seven endoscopists. Baseline patient demographics were similar, with median age of 60 years with a slight female predominance (52.1%). Procedure indications, bowel preparation quality, and caecal intubation rates were comparable between groups. AIAC had a slightly longer withdrawal time compared to CC, but the difference was not statistically significant. The introduction of AIAC did not significantly change ADR (52.1% for AIAC vs 52.6% for CC, P = 0.91) or SSLDR (17.4% for AIAC vs 18.1% for CC, P = 0.44).

CONCLUSION

The implementation of AIAC failed to improve key markers of colonoscopy quality, including ADR, SSLDR and withdrawal time. Further research is required to assess the utility and cost-efficiency of AIAC for high performing endoscopists.

Cold snare polypectomy compared to cold forceps polypectomy for endoscopic resection of guideline defined diminutive polyps: A systematic review and meta-analysis of randomized trials

BACKGROUND

International guidelines recommend cold snare polypectomy (CSP) for polyps  < 10 mm in size. However, recent randomized clinical trials (RCTs) showed conflicting results for the use of cold forceps polypectomy (CFP) vs. CSP for the resection of diminutive colorectal polyps (DCPs) (≤ 5 mm), especially for polyps  ≤ 3 mm. Herein we compared CFP with CSP for patients with DCPs in this meta-analysis of RCTs.

METHODS

We systematically searched the Cochrane Library, PubMed and EMBASE databases from inception to November 24, 2022, (Registration number INPLASY2022110135). The primary endpoint was DCP complete resection rate. The secondary endpoints were mean polypectomy time, polyp retrieval rate and complications.

RESULTS

Seven RCTs involving 1023 DCPs were included. The complete resection rate (91.6% vs. 94.7%) for CFP was not significantly lower for polyps ≤ 5 mm (relative risk [RR] = 1.03; 95% confidence interval [CI]: 0.98-1.07). Sub-group analysis showed that the complete resection rate (88.7% vs. 92.4%) for CFP was not significantly lower for DCPs > 3 mm (RR = 1.04; 95% CI: 0.97-1.12). Another sub-group analysis showed that the complete resection rate (97.0% vs. 96.3%) was similar for polyps ≤ 3 mm for CFP vs. CSP (RR = 1.00; 95% CI: 0.98-1.03). The mean polypectomy time was not different between CFP and CSP (95% CI: -11.86-10.18). The polyp retrieval rate (100% vs. 96.9%) was not significantly higher for CFP (RR = 1.02; 95% CI: 0.98-1.07). There were no reported complications in the included studies. The overall study quality was moderate except for the removal of polyps ≤ 5 mm (low-quality evidence).

CONCLUSION

CFP was comparable to CSP for the resection of polyps ≤ 3 mm; however, caution should be taken for DCPs > 3 mm because of the low complete resection rate (< 90%).

Profiling small RNAs in fecal immunochemical tests: is it possible?

Fecal microRNAs represent promising molecules with potential clinical interest as non-invasive diagnostic and prognostic biomarkers. Colorectal cancer (CRC) screening based on the fecal immunochemical test (FIT) is an effective tool for prevention of cancer development. However, due to the poor sensitivity of FIT especially for premalignant lesions, there is a need for implementation of complementary tests. Improving the identification of individuals who would benefit from further investigation with colonoscopy using molecular analysis, such as miRNA profiling of FIT samples, would be ideal due to their widespread use. In the present study, we assessed the feasibility of applying small RNA sequencing to measure human miRNAs in FIT leftover buffer in samples from two European screening populations. We showed robust detection of miRNAs with profiles similar to those obtained from specimens sampled using the established protocol of RNA stabilizing buffers, or in long-term archived samples. Detected miRNAs exhibited differential abundances for CRC, advanced adenoma, and control samples that were consistent for FIT and RNA-stabilizing buffers. Interestingly, the sequencing data also allowed for concomitant evaluation of small RNA-based microbial profiles. We demonstrated that it is possible to explore the human miRNome in FIT leftover samples across populations and envision that the analysis of small RNA biomarkers can complement the FIT in large scale screening settings.

pT1 colorectal cancer: A treatment dilemma

The implementation of population screening programs for colorectal cancer (CRC) has led to a considerable increase in the prevalence pT1-CRC originating on polyps amenable by local treatments. However, a high proportion of patients are referred for unnecessary oncological surgeries without a clear benefit in terms of survival. Selecting the appropriate endoscopic resection technique in the moment of diagnosis becomes crucial to provide the best treatment alternative to each individual polyp and patient. For this, it is imperative to increase the optical diagnostic skill for differentiating pT1-CRCs and decide the appropriate initial therapy. En bloc resection is crucial to obtain an adequate histological specimen that might allow organ preserving therapeutic management. In this review, we address key challenges in T1 CRC management, explore the efficacy and safety of the available diagnostic and therapeutic approaches, and shed light on upcoming advances in the field.

Economic impact of implementing optical diagnosis with a "resect and discard" strategy within the English Bowel Cancer Screening Programme: findings from the DISCARD3 study

BACKGROUND AND AIMS

Advances in endoscopic technology, such as narrow-band imaging and high-definition colonoscopes, offer the potential for optical diagnosis (OD) with a "resect and discard" (RD) strategy for diminutive (≤5 mm) and small (6-9 mm) colorectal polyps. This could help alleviate the huge cost and time burden required for histopathology. The aim of this study was to conduct an economic analysis of an RD strategy within the English Bowel Cancer Screening Programme (BCSP).

METHODS

A decision tree was designed to compare an RD strategy with standard histopathology for patients included in the DISCARD3 study (Detect InSpect ChAracterise Resect and Discard 3) and was extrapolated to a national BCSP patient cohort.

RESULTS

Of the 525 patients in the DISCARD3 study, 354 were assessed for surveillance intervals (after excluding cases with colorectal cancer and at least 1 polyp >10 mm). Of 354 patients, 269 had polyps, of which 182 had only diminutive polyps, 77 had both small and diminutive polyps, and 10 had only small polyps. Surveillance interval concordance was 97.9% in patients with at least 1 diminutive polyp and 98.7% in patients with at least 1 diminutive or small polyp. In DISCARD3, an RD approach was found to reduce overall direct healthcare costs by $44,285.63 (-72.3%) for patients with diminutive polyps or by $66,129.13 (-75.0%) for patients with diminutive or small polyps. When extrapolated to the entire English BCSP, the annual savings were almost $3 million for patients with diminutive polyps or $4.3 million for patients with diminutive or small polyps, after adjusting for the costs of an OD quality assurance process.

CONCLUSIONS

OD with an RD strategy for diminutive and small polyps during BCSP colonoscopy would offer substantial cost savings without adversely affecting surveillance interval concordance.

Artificial Intelligence Applied to Colonoscopy: Is It Time to Take a Step Forward?

Growing evidence indicates that artificial intelligence (AI) applied to medicine is here to stay. In gastroenterology, AI computer vision applications have been stated as a research priority. The two main AI system categories are computer-aided polyp detection (CADe) and computer-assisted diagnosis (CADx). However, other fields of expansion are those related to colonoscopy quality, such as methods to objectively assess colon cleansing during the colonoscopy, as well as devices to automatically predict and improve bowel cleansing before the examination, predict deep submucosal invasion, obtain a reliable measurement of colorectal polyps and accurately locate colorectal lesions in the colon. Although growing evidence indicates that AI systems could improve some of these quality metrics, there are concerns regarding cost-effectiveness, and large and multicentric randomized studies with strong outcomes, such as post-colonoscopy colorectal cancer incidence and mortality, are lacking. The integration of all these tasks into one quality-improvement device could facilitate the incorporation of AI systems in clinical practice. In this manuscript, the current status of the role of AI in colonoscopy is reviewed, as well as its current applications, drawbacks and areas for improvement.

Colon Capsule Endoscopy - Shining the Light through the Colon

PURPOSE OF REVIEW

Colon capsule endoscopy (CCE) is a non-invasive, wireless capsule endoscope. In this article, we review its current applications, compare its performance with optical colonoscopy (OC) and alternative imaging modalities like CT colonography (CTC), and highlight developments that may increase potential future use.

RECENT FINDINGS

By comparison to OC both CCE and CTC have a good sensitivity and specificity in detecting colonic polyps. CCE is more sensitive in detecting sub centimetre polyps. CCE is capable of detecting colonic inflammation and anorectal pathologies, commonly missed by CTC. However, rates of complete CCE examinations are limited by inadequate bowel preparation or incomplete colonic transit, whereas CTC can be performed with less bowel purgatives. Patients tolerate CCE better than OC, however patient preference between CCE and CTC vary. CCE and CTC are both reasonable alternatives to OC. Strategies to improve completion rates and adequacy of bowel preparation will improve cost and clinical effectiveness of CCE.

Usefulness of a novel computer-aided detection system for colorectal neoplasia: a randomized controlled trial

BACKGROUND AND AIMS

Artificial intelligence-based computer-aid detection (CADe) devices have been recently tested in colonoscopies, increasing the adenoma detection rate (ADR), mainly in Asian populations. However, evidence for the benefit of these devices in the occidental population is still low. We tested a new CADe device, namely, ENDO-AID (OIP-1) (Olympus, Tokyo, Japan), in clinical practice.

METHODS

This randomized controlled trial included 370 consecutive patients who were randomized 1:1 to CADe (n = 185) versus standard exploration (n = 185) from November 2021 to January 2022. The primary endpoint was the ADR. Advanced adenoma was defined as ≥10 mm, harboring high-grade dysplasia, or with a villous pattern. Otherwise, the adenoma was nonadvanced. ADR was assessed in both groups stratified by endoscopist ADR and colon cleansing.

RESULTS

In the intention-to-treat analysis, the ADR was 55.1% (102/185) in the CADe group and 43.8% (81/185) in the control group (P = .029). Nonadvanced ADRs (54.8% vs 40.8%, P = .01) and flat ADRs (39.4 vs 24.8, P = .006), polyp detection rate (67.1% vs 51%; P = .004), and number of adenomas per colonoscopy were significantly higher in the CADe group than in the control group (median [25th-75th percentile], 1 [0-2] vs 0 [0-1.5], respectively; P = .014). No significant differences were found in serrated ADR. After stratification by endoscopist and bowel cleansing, no statistically significant differences in ADR were found.

CONCLUSIONS

Colonoscopy assisted by ENDO-AID (OIP-1) increases ADR and number of adenomas per colonoscopy, suggesting it may aid in the detection of colorectal neoplastic lesions, especially because of its detection of diminutive and flat adenomas. (Clinical trial registration number: NCT04945044.).

New management of surveillance in patients with baseline serrated polyps: a large single-center retrospective cohort study in China

BACKGROUND

Serrate d polyps (SP) is associated with an increased risk of colorectal cancer. Patients with SP history tend to have SP recurrence. However, the risk factors for metachronous polyps (MP) in those patients are not well established.

METHODS

Data of colonoscopy were retrospectively reviewed from October 2012 to October 2021. The pathology database, electronic medical records and telephone follow-up data were also observed.

RESULTS

A total of 906 patients were studied including 278 patients with MPs and 628 patients without. The multiplicity of polyps (OR, 13.63; 95% CI, 8.80-21.75), older age (OR, 5.71; 95% CI, 1.87-20.63), abdominal obesity (OR, 2.46; 95% CI, 0.98-6.42), current smoker (OR, 2.93; 95% CI, 1.15-7.83) and sedentary lifestyle (OR, 1.41; 95% CI, 1.22-1.65) are significantly associated with the risk of MPs. Patients with baseline SP < 10 mm were more likely to develop higher or same risk-grade polyps (HSRGP) ( P  = 0.0014). Patients with non-clinically significant SPs whether coexisted with adenoma or not were more likely to develop HSRGPs when compared to others ( P  < 0.001).

CONCLUSION

Total number of polyps, older age, sedentary behavior, abdominal obesity and smoking status contributed to the risk of MPs at surveillance colonoscopy. Patients with grade 1 SPs might require closer surveillance. SPs coexisting with conventional adenoma did not increase the risk of MPs but may increase the risk of developing HSRGPs.

Accuracy and Inter-observer Agreement Among Endoscopists for Visual Identification of Colorectal Polyps Using Endoscopy Images

BACKGROUND

It is essential to accurately distinguish small benign hyperplastic colon polyps (HP) from sessile serrated lesions (SSL) or adenomatous polyps (TA) based on endoscopic appearances. Our objective was to determine the accuracy and inter-observer agreements for the endoscopic diagnosis of small polyps.

METHODS

High-quality endoscopic images of 30 small HPs, SSLs, and TAs were used randomly to create two-timed PowerPoint slide sets-one with and another one without information on polyp size and location. Seven endoscopists viewed the slides on two separate occasions 90 days apart, identified the polyp type, and graded their confidence level. Overall and polyp-specific accuracies were assessed for the group and individual endoscopists. Chi-square tests and Kappa (κ) statistics were used to compare differences as appropriate.

RESULTS

When polyp size and location were provided, overall accuracy was 67.1% for TAs, 50.0% for SSLs, and 41.4% for HPs; the corresponding accuracies were 60%, 44.3%, and 34.3% when polyp size and location were withheld (p < .001). Inter-observer agreement was moderate for TAs (κ = 0.50) and fair for SSLs (κ = 0.26) and HPs (κ = 0.29); the corresponding inter-observer agreements were 0.44, 0.31, and 0.17 with polyp size and location withheld. Accuracy was not affected by knowledge of polyp size, location, or confidence level. Endoscopists with ≥ 10 years (vs. < 10 years) of colonoscopy experience had marginally higher (56% vs. 40%, p = 0.05) accuracy for SSL diagnosis.

CONCLUSIONS

The ability to distinguish between small TAs, SSLs, and HPs on their endoscopic appearance is poor regardless of the endoscopists' knowledge of polyp size and location.

Sporadic Rectocolic Polyps Prevalence and Management

Objective To evaluate the prevalence of polyps and their treatments.

Materials and Method This is a retrospective study conducted in our department over 20 years and 3 months between January 2000 and March 2021. All patients with colorectal polyps who underwent endoscopic resection were included. We evaluated the resection techniques and the management of complications.

Results The total number of patients was 273, with a mean age of 57.26 ± 14.058 (18–90) and a M/W sex ratio of 2. The prevalence was 3.35% and the mean number of polyps was 1.33 ± 0.69. The most frequent symptoms were rectal bleeding (23.5%) and constipation (12.1%). The median size was 6 mm (4–12 mm). The left colonic location was the most frequent site (43%). All polyps were classified according to the Paris classification, with a predominance of sessile polyps in 45.75%, followed by pedunculated polyps, representing 42.4%. Endoscopic resection was performed either by biopsy forceps, polypectomy, or mucosectomy in 30.2%, 27.4%, and 25.4% of cases, respectively. Our study noted immediate bleeding in 1.5% of cases, and no perforations or late complications. All complications were treated endoscopically, and no patient required blood transfusion or surgical intervention.

Conclusion Endoscopic resection of rectocolic polyps is the ideal treatment for these lesions. In our department, the prevalence was 3.35%, the most used resection techniques were forceps resection and polypectomy, and the complication rate was 1.5%.

Complete polyp resection with cold snare versus hot snare polypectomy for polyps of 4-9 mm: a randomized controlled trial

BACKGROUND

Endoscopic screening with polypectomy reduces the incidence of colorectal cancer (CRC). Incomplete polyp removal may attenuate the effect of screening. This randomized trial compared cold snare polypectomy (CSP) with hot snare polypectomy (HSP) in terms of complete polyp resection.

METHODS

We included patients ≥ 40 years of age at eight hospitals in four countries who had at least one non-pedunculated polyp of 4-9 mm detected at colonoscopy. Patients were randomized 1:1 to CSP or HSP. Biopsies from the resection margins were obtained systematically after polypectomy in both groups. We hypothesized that CSP would be non-inferior to HSP, with a non-inferiority margin of 5 %. Logistic regression models were fitted to identify the factors explaining incomplete resection.

RESULTS

425 patients, with 601 polyps, randomized to either CSP or HSP were included in the analysis. Of 318 polyps removed by CSP and 283 polyps removed by HSP, 34 (10.7 %) and 21 (7.4 %) were incompletely resected, respectively, with an adjusted risk difference of 3.2 % (95 %CI -1.4 % to 7.8 %). There was no difference between the groups in terms of post-polypectomy bleeding, perforation, or abdominal pain. Independent risk factors for incomplete removal were serrated histology (odds ratio [OR] 3.96; 95 %CI 1.63 to 9.66) and hyperplastic histology (OR 2.52; 95 %CI 1.30 to 4.86) in adjusted analyses.

CONCLUSION

In this randomized trial, non-inferiority for CSP could not be demonstrated. Polyps with serrated histology are more prone to incomplete resection compared with adenomas. CSP can be used safely for small polyps in routine colonoscopy practice.

Short and long-term psychosocial consequences of participating in a colorectal cancer screening programme: a matched longitudinal study

OBJECTIVES

To investigate the psychosocial consequences of receiving a false-positive (no abnormalities) result or being diagnosed with polyps compared with receiving a negative result in a colorectal cancer (CRC) screening programme.

DESIGN AND SETTING

This was a longitudinal study nested in the roll-out of the Danish CRC screening programme that targets all individuals aged 50-74 years.

PARTICIPANTS

In the inclusion period (April-September 2017), all positive screenees (n=1854) were consecutively enrolled and matched 2:1:1 on sex, age (±2 years), municipality and screening date with negative screenees (n=933) and individuals not yet invited to screening (n=933).Questionnaires were sent by mail to all eligible participants in Region Zealand, Denmark, after the screening result, 2 months and 12 months after the final result.Positive screenees who did not receive the follow-up procedure were excluded.

MAIN OUTCOME MEASURES

The primary outcomes were psychosocial consequences. Outcomes were measured with the CRC screening-specific questionnaire Consequences of screening in CRC with 11 outcomes after the screening result and with 21 outcomes at the two later assessments.

RESULTS

After receiving the screening result, individuals with no abnormalities, low-risk and medium-risk and high-risk polyps scored significantly worse on 8 of 11 outcomes compared with the negative screenee group. At the 12-month follow-up, the differences were still significant in 8 of 21 outcomes (no abnormalities), 4 of 21 outcomes (low-risk polyps) and 10 of 21 outcomes (medium-risk and high-risk polyps). The negative screenee group and the group not yet invited to screening differed psychosocially on 5 of 11 outcomes after the screening result, but on none of the 21 outcomes at the 2 months and 12 months follow-up.

CONCLUSIONS

The study showed that there are both short-term and long-term psychosocial consequences associated with receiving a no abnormalities result or being diagnosed with polyps. The consequences were worst for individuals diagnosed with medium-risk and high-risk polyps.

ScotCap - A large observational cohort study

AIM

The aim of this work was to evaluate the performance of colon capsule endoscopy (CCE) in a lower gastrointestinal diagnostic care pathway.

METHOD

This large multicentre prospective clinical evaluation recruited symptomatic patients (patients requiring investigation of symptoms suggestive of colorectal pathology) and surveillance patients (patients due to undergo surveillance colonoscopy). Patients aged 18 years or over were invited to participate and undergo CCE by a secondary-care clinician if they met the referral criteria for a colonoscopy. The primary outcome was the test completion rate (visualization of the whole colon and rectum). We also measured the need for further tests after CCE.

RESULTS

A total of 733 patients were invited to take part in this evaluation, with 509 patients undergoing CCE. Of these, 316 were symptomatic patients and 193 were surveillance patients. Two hundred and twenty-eight of the 316 symptomatic patients (72%) and 137 of the 193 surveillance patients (71%) had a complete test. It was found that 118/316 (37%) of symptomatic patients required no further test following CCE, while 103/316 (33%) and 81/316 (26%) required a colonoscopy and flexible sigmoidoscopy, respectively. Fifty-three of the 193 surveillance patients (28%) required no further test following CCE, while 104/193 (54%) and 30/193 (16%) required a colonoscopy and flexible sigmoidoscopy, respectively. No patient in this evaluation was diagnosed with colorectal cancer. Two patients experienced serious adverse events - one capsule retention with obstruction and one hospital admission with dehydration due to the bowel preparation.

CONCLUSION

CCE is a safe, well-tolerated diagnostic test which can reduce the proportion of patients requiring colonoscopy, but the test completion rate needs to be improved to match that of lower gastrointestinal endoscopy.

Cause, Epidemiology, and Histology of Polyps and Pathways to Colorectal Cancer

Colorectal cancer is the second leading cause of cancer-associated mortality, with a lifetime risk of approximately 4% to 5%. Colorectal cancer develops from the sequential acquisition of defined genetic mutations in the colonic epithelium. Tumorigenesis from normal tissue to cancer occurs largely through 3 pathways: the chromosomal instability pathway, the microsatellite instability pathway, and the sessile serrated pathway. Colorectal cancer incidence and mortality have decreased by approximately 35% since the beginning of screening programs in the 1990s, although other factors such as use of aspirin for coronary disease prevention and decreased smoking rates may also be important. In this review, we discuss the etiology, epidemiology, and histology of colorectal polyps and cancer.

Comparison of cold biopsy forceps vs cold snare for diminutive colorectal polyp removal: A multicenter non-inferiority randomized controlled trial

BACKGROUND

European guidelines recommends the use of cold snare polypectomy (CSP) for removal of diminutive colorectal polyps (DCP). However, for DCP < 4 mm cold biopsy forceps (CBF) may be optional. We aimed to compare the efficacy of CSP with CBF for removal of DCP in routine colonoscopy.

METHODS

We conducted a multicenter non-inferiority randomized controlled trial. After screening, 123 patients were prospectively included and 180 DCPs were removed by either CBF or CSP after randomization (1:1). The primary end-point was the histological complete resection rate defined by negative additional biopsies taken from the edge of the polypectomy ulcer site.

RESULTS

Among DCPs, 121 (67.2%) adenomas or sessile serrated lesions were considered for the analysis. Polyps were 4 [1-5] mm in size, mostly flat (55.4%) and located in the proximal colon (44.6%). The en bloc resection rate was higher in the CSP group than the CBF group (91.7% vs. 42.6%, p < 0.001). The histological complete resection rate was comparable in the two groups (93.33% vs 90.16%; p = 0.527), even for polyps < 4 mm (91.30% vs 91.30%; p = 1). All specimens were retrieved and there was no difference in terms of procedure times and adverse events. Finally, univariate analysis did not identify any potential factor associated with complete resection rate.

CONCLUSION

In this study, CSP was comparable to CBF for the removal of DCP. Therefore, CBF may be considered as an alternative technique for resection of DCP, together with CSP, ClinicalTrials.gov registry (NCT04727918).

Artificial intelligence-assisted colonoscopy: a narrative review of current data and clinical applications

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.

Real-time diagnostic accuracy of blue light imaging, linked color imaging and white-light endoscopy for colorectal polyp characterization

Background and study aims  Fujifilm has developed a novel ELUXEO 7000 endoscope system that employs light-emitting diodes (LEDs) at four different wavelengths as light sources that enable blue light imaging (BLI), linked color imaging (LCI), and high-definition white-light endoscopy (HD-WLE). The aim of this study was to address the diagnostic accuracy of real-time polyp characterization using BLI, LCI and HD-WLE (ELUXEO 7000 endoscopy system). Patients methods  This is a prespecified post-hoc analysis of a prospective study in which 22 experienced endoscopists (> 2,000 colonoscopies) from eight international centers participated. Using a combination of BLI, LCI, and HD-WLE, lesions were endoscopically characterized including a high- or low-confidence statement. Per protocol, digital images were created from all three imaging modalities. Histopathology was the reference standard. Endoscopists were familiar with polyp characterization, but did not take dedicated training for purposes of this study. Results  Overall, 341 lesions were detected in 332 patients. Of the lesions, 269 histologically confirmed polyps with an optical diagnosis were included for analysis (165 adenomas, 27 sessile serrated lesions, and 77 hyperplastic polyps). Overall, polyp characterization was performed with high confidence in 82.9 %. The overall accuracy for polyp characterization was 75.1 % (95 % confidence interval [CI] 69.5-80.1 %), compared with an accuracy of 78.0 % (95 % CI 72.0-83.2 %) for high confidence assignments. The accuracy for endoscopic characterization for diminutive polyps was 74.7 % (95 %CI 68.4-80.3 %), compared with an accuracy of 78.2 % (95 % CI 71.4-84.0 %) for high-confidence assignments. Conclusions  The diagnostic accuracy of BLI, LCI, and HD-WLE by experienced endoscopist for real-time polyp characterization seems limited (NCT03344289).

Can image-enhanced endoscopy improve adenoma detection rate?

An accumulating body of evidence has shown that detection and resection of pre-cancerous adenoma by colonoscopy could effectively prevent colorectal cancer (CRC) and its related mortality. Among various colonoscopy quality indicators, such as cecal intubation rate, withdrawal time, and adenoma detection rate (ADR); ADR is the most important and most closely associated with the subsequent risk of CRC. Image-enhanced endoscopy (IEE), including digital and dye-based IEE, was originally developed to discriminate neoplastic from non-neoplastic lesions but later studies have demonstrated that it can also enhance lesion detection by enhancing the contrast between the lesion and background colonic mucosa. Nevertheless, using IEE in colonoscopy for lesion detection is still not the standard way of practice in the real world. For a better understanding of current IEE modalities, this review introduces and compares the currently available IEE modalities and their efficacy in detecting adenoma from the results of randomized controlled trials or meta-analyses.

Definition of competence standards for optical diagnosis of diminutive colorectal polyps: European Society of Gastrointestinal Endoscopy (ESGE) Position Statement

BACKGROUND : The European Society of Gastrointestinal Endoscopy (ESGE) has developed a core curriculum for high quality optical diagnosis training for practice across Europe. The development of easy-to-measure competence standards for optical diagnosis can optimize clinical decision-making in endoscopy. This manuscript represents an official Position Statement of the ESGE aiming to define simple, safe, and easy-to-measure competence standards for endoscopists and artificial intelligence systems performing optical diagnosis of diminutive colorectal polyps (1 - 5 mm). METHODS : A panel of European experts in optical diagnosis participated in a modified Delphi process to reach consensus on Simple Optical Diagnosis Accuracy (SODA) competence standards for implementation of the optical diagnosis strategy for diminutive colorectal polyps. In order to assess the clinical benefits and harms of implementing optical diagnosis with different competence standards, a systematic literature search was performed. This was complemented with the results from a recently performed simulation study that provides guidance for setting alternative competence standards for optical diagnosis. Proposed competence standards were based on literature search and simulation study results. Competence standards were accepted if at least 80 % agreement was reached after a maximum of three voting rounds. RECOMMENDATION 1:  In order to implement the leave-in-situ strategy for diminutive colorectal lesions (1-5 mm), it is clinically acceptable if, during real-time colonoscopy, at least 90 % sensitivity and 80 % specificity is achieved for high confidence endoscopic characterization of colorectal neoplasia of 1-5 mm in the rectosigmoid. Histopathology is used as the gold standard.Level of agreement 95 %. RECOMMENDATION 2:  In order to implement the resect-and-discard strategy for diminutive colorectal lesions (1-5 mm), it is clinically acceptable if, during real-time colonoscopy, at least 80 % sensitivity and 80 % specificity is achieved for high confidence endoscopic characterization of colorectal neoplasia of 1-5 mm. Histopathology is used as the gold standard.Level of agreement 100 %. CONCLUSION : The developed SODA competence standards define diagnostic performance thresholds in relation to clinical consequences, for training and for use when auditing the optical diagnosis of diminutive colorectal polyps.

Effectiveness and safety of the different endoscopic resection methods for 10- to 20-mm nonpedunculated colorectal polyps: A systematic review and pooled analysis

BACKGROUND

We performed a systematic review and pooled analysis to assess the effectiveness and safety of different endoscopic resection methods for 10- to 20-mm nonpedunculated colorectal polyps.

METHODS

Articles in PubMed, EMBASE, and the Cochrane Library related to the common endoscopic treatment of 10- to 20-mm nonpedunculated polyps published as of April 2020 were searched. Primary outcomes were the R0 resection rate and en bloc resection rate. Secondary outcomes were safety and the recurrence rate. Meta-regression and subgroup analysis were also performed.

RESULTS

A total of 36 studies involving 3212 polyps were included in the final analysis. Overall, the effectiveness of resection methods with a submucosal uplifting effect, including endoscopic mucosal resection (EMR), cold EMR and underwater EMR (UEMR), was better than that of methods without a nonsubmucosal uplifting effect [R0 resection rate, 90% (95% confidence interval (CI) 0.81-0.94, I² = 84%) vs 82% (95% CI 0.78-0.85, I² = 0%); en bloc resection rate 85% (95% CI 0.79-0.91, I² = 83%) vs 74% (95% CI 0.47-0.94, I² = 94%)]. Regarding safety, the pooled data showed that hot resection [hot snare polypectomy, UEMR and EMR] had a higher risk of intraprocedural bleeding than cold resection [3% (95% CI 0.01-0.05, I² = 68%) vs 0% (95% CI 0-0.01, I² = 0%)], while the incidences of delayed bleeding, perforation and post-polypectomy syndrome were all low.

CONCLUSIONS

Methods with submucosal uplifting effects are more effective than those without for resecting 10- to 20-mm nonpedunculated colorectal polyps, and cold EMR is associated with a lower risk of intraprocedural bleeding than other methods. Additional research is needed to verify the advantages of these methods, especially cold EMR.

Guidance for setting easy-to-adopt competence criteria for optical diagnosis of diminutive colorectal polyps: a simulation approach

BACKGROUND AND AIMS

One reason the optical diagnosis strategy for diminutive colorectal polyps has not yet been implemented is that the current competence criteria (Preservation and Incorporation of Valuable Endoscopic Innovation [PIVI] initiative) are difficult to use in daily practice. To provide guidance for setting alternative easy-to-adopt competence criteria, we determined the lowest proportion of diminutive polyps that should have a correct optical diagnosis to meet the PIVI.

METHODS

For this simulation study, we used datasets from 2 prospectively collected cohorts of patients who underwent colonoscopy in either a primary colonoscopy or fecal immunochemical test (FIT) screening setting. In the simulation approach, virtual endoscopists or computer-aided diagnosis systems performed optical diagnosis of diminutive polyps with a fixed diagnostic performance level (strategy) on all individuals in the cohort who had ≥1 diminutive polyp. Strategies were defined by systematically varying the proportion of correct optical diagnoses for each polyp subtype (ie, adenomas, hyperplastic polyps, sessile serrated lesions). For each strategy, we determined whether PIVI-1 (≥90% agreement with U.S. or European Society for Gastrointestinal Endoscopy [ESGE] surveillance guidelines) and PIVI-2 (≥90% negative predictive value [NPV] for neoplastic lesions in the rectosigmoid) were met using Monte Carlo sampling with 1000 repetitions, with histology as reference.

RESULTS

The level of overall diagnostic accuracy to achieve the PIVI differed significantly depending on the clinical setting and guidelines used. In the colonoscopy screening setting, all diagnostic strategies in which 92% of all diminutive polyps (regardless of histology) were diagnosed correctly led to 90% or more agreement with U.S. surveillance intervals (ie, PIVI-1). For all diagnostic strategies in which ≥89% of all diminutive polyps were correctly diagnosed, at least 90% NPV was achieved (ie, PIVI-2). For the FIT screening setting, values were respectively ≥77% and ≥94%. When using ESGE guidelines, PIVI-1 was in both settings already met when 40% of all diminutive polyps were diagnosed correctly.

CONCLUSIONS

In contrast to the fixed PIVI criteria, our simulation study shows that different thresholds for the proportion of correctly diagnosed diminutive polyps lead to different clinical consequences depending on guidelines and clinical setting. However, this target proportion of diminutive colorectal polyps correctly diagnosed with optical diagnosis represents easier-to-adopt competence criteria.

Platelet-to-lymphocyte ratio and C-reactive protein as markers for colorectal polyp histological type

Background

The platelet-to-lymphocyte ratio (PLR) and C-reactive protein (CRP) level are markers that have been reported to predict the histological type of various tumors, and here, we evaluated their utility in predicting colorectal polyp histological types.

Methods

We retrospectively reviewed 172 patients with colorectal polyps who underwent endoscopic polypectomy. The associations between histological type and clinicopathologic parameters were assessed by multivariate analysis.

Results

The optimal PLR and CRP cut-off values were 113.32 and 0.39, respectively. The PLR (P = 0.002) and CRP (P = 0.009) values were associated with the histological type according to the univariate analysis, whereas low PLR (P ≤ 0.001) and CRP (P = 0.017) values were independent risk factors in the multivariate analysis together with maximum tumor diameter (P ≤ 0.001) and tumor number (P = 0.0014).

Conclusions

Preoperative PLR and CRP are correlated with the colorectal polyp histological type.

Colonoscopy screening and surveillance guidelines

The Colonoscopy Screening and Surveillance Guidelines were developed by the Japan Gastroenterological Endoscopy Society as basic guidelines based on the scientific methods. The importance of endoscopic screening and surveillance for both detection and post-treatment follow-up of colorectal cancer has been recognized as essential to reduce disease mortality. There is limited high-level evidence in this field; therefore, we had to focus on the consensus of experts. These clinical practice guidelines consist of 20 clinical questions and eight background knowledge topics that have been determined as the current guiding principles.

Colonoscopy and artificial intelligence: Bridging the gap or a gap needing to be bridged?

Research in artificial intelligence (AI) in gastroenterology has increased over the last decade. Colonoscopy represents the most widely published field with regards to its use in gastroenterology. Most studies to date center on polyp detection and characterization, as well as real-time evaluation of adequacy of mucosal exposure for inspection. This review article discusses how advances in AI has bridged certain gaps in colonoscopy. In addition, the gaps formed with the development of AI that currently prevent its routine use in colonoscopy will be explored.

Evidence-based clinical practice guidelines for management of colorectal polyps

BACKGROUND

The Japanese Society of Gastroenterology (JSGE) published ''Daicho Polyp Shinryo Guideline 2014'' in Japanese and a part of this guideline was published in English as "Evidence-based clinical practice guidelines for management of colorectal polyps" in the Journal of Gastroenterology in 2015. A revised version of the Japanese-language guideline was published in 2020, and here we introduce a part of the contents of revised version.

METHODS

The guideline committee discussed and drew up a series of clinical questions (CQs). Recommendation statements for the CQs were limited to items with multiple therapeutic options. Items with established conclusions that had 100% agreement with previous guidelines (background questions) and items with no (or old) evidence that are topics for future research (future research questions: FRQs) were given descriptions only. To address the CQs and FRQs, PubMed, ICHUSHI, and other sources were searched for relevant articles published in English from 1983 to October 2018 and articles published in Japanese from 1983 to November 2018. The Japan Medical Library Association was also commissioned to search for relevant materials. Manual searches were performed for questions with insufficient online references.

RESULTS

The professional committee created 18 CQs and statements concerning the current concept and diagnosis/treatment of various colorectal polyps, including their epidemiology, screening, pathophysiology, definition and classification, diagnosis, management, practical treatment, complications, and surveillance after treatment, and other colorectal lesions (submucosal tumors, nonneoplastic polyps, polyposis, hereditary tumors, ulcerative colitis-associated tumors/carcinomas).

CONCLUSIONS

After evaluation by the moderators, evidence-based clinical practice guidelines for management of colorectal polyps were proposed for 2020. This report addresses the therapeutic related CQs introduced when formulating these guidelines.

Incomplete endoscopic resection of colorectal polyps: a prospective quality assurance study

BACKGROUND

 Endoscopic screening with polypectomy has been shown to reduce colorectal cancer incidence in randomized trials. Incomplete polyp removal and subsequent development of post-colonoscopy cancers may attenuate the effect of screening. This study aimed to quantify the extent of incomplete polyp removal.

METHODS

 We included patients aged 50-75 years with nonpedunculated polyps ≥ 5 mm removed during colonoscopy at four hospitals in Norway. To evaluate completeness of polyp removal, biopsies from the resection margins were obtained after polypectomy. Logistic regression models were fitted to identify factors explaining incomplete resection.

RESULTS

 246 patients with 339 polyps underwent polypectomy between January 2015 and June 2017. A total of 12 polyps were excluded due to biopsy electrocautery damage, and 327 polyps in 246 patients (mean age 67 years [range 42-83]; 52 % male) were included in the analysis. Overall, 54 polyps (15.9 %) in 54 patients were incompletely resected. Histological diagnosis of the polyp (sessile serrated lesions vs. adenoma, odds ratio [OR] 10.9, 95 % confidence interval [CI] 3.9-30.1) and polyp location (proximal vs. distal colon, OR 2.8, 95 %CI 1.0-7.7) were independent risk factors for incomplete removal of polyps 5-19 mm. Board-certified endoscopists were not associated with lower rates of incomplete resection compared with trainees (14.0 % vs. 14.2 %), OR 1.0 (95 %CI 0.5-2.1).

CONCLUSION

Incomplete polyp resection was frequent after polypectomy in routine clinical practice. Serrated histology and proximal location were independent risk factors for incomplete resection. The performance of board-certified gastroenterologists was not superior to that of trainees.

Effect of Instruction on Preventing Delayed Bleeding after Colorectal Polypectomy and Endoscopic Mucosal Resection

Background: The frequency of delayed bleeding after colorectal polypectomy has been reported as 0.6–2.8%. With the increasing performance of polypectomy under continuous use of antithrombotic agents, care is required regarding delayed post-polypectomy bleeding (DPPB). Better instruction to educate endoscopists is therefore needed. We aimed to evaluate the effect of instruction and factors associated with delayed bleeding after endoscopic colorectal polyp resection. Methods: This single-center, retrospective study was performed to assess instruction in checking complete hemostasis and risk factors for onset of DPPB. The incidence of delayed bleeding, comorbidities, and medications were evaluated from medical records. Characteristics of historical control patients and patients after instruction were compared. Results: A total of 3318 polyps in 1002 patients were evaluated. The control group comprised 1479 polyps in 458 patients and the after-instruction group comprised 1839 polyps in 544 patients. DPPB occurred in 1.1% of polyps in control, and 0.4% in after-instruction. Instruction significantly decreased delayed bleeding, particularly in cases with antithrombotic agents. Hot polypectomy, clip placement, and use of antithrombotic agents were significant independent risk factors for DPPB even after instruction. Conclusion: The rate of delayed bleeding significantly decreased after instruction to check for complete hemostasis. Even after instruction, delayed bleeding can still occur in cases with antithrombotic agents or hot polypectomy.

A Correctional-Public Health Collaboration for Colorectal Cancer Screening in a State Prison System

Correctional facilities provide health care to large numbers of medically underserved people. As such, preventive health in correctional settings is an important yet underused investment in public health. Because they often have histories of poor access to health care, the justice-involved population is more likely than the general population to be diagnosed with advanced-stage cancers. We report on the first 2 years of an ongoing collaboration between a state correctional system and state health department to implement annual colorectal cancer screening for sentenced people using fecal immunochemical testing (FIT). Preparation for the annual iterations begins in January, and patient engagement begins in March. In the first year of implementation (2018), 1396 of 1856 (75.2%) sentenced people completed an eligibility screen, and 254 of 321 (79.1%) eligible patients completed a FIT (eligible patients were aged ≥50 [≥45 if Black] in year 1 [lowered to ≥45 in year 2] and reported no previous relevant medical or family history of colorectal cancer); 54 (21.3%) completed FITs were positive. Of the 54 patients with positive FITS, 33 (61.1%) completed follow-up colonoscopies resulting in the identification of polyps in 26 (48.1%) patients with a positive FIT. We found invasive adenocarcinoma for 2 (3.7%) of the positive FITs (6.1% of colonoscopies performed). In the second year (2019), after a conversion from paper to tablet-based eligibility screening, 1707 of 2059 (82.9%) sentenced people completed an eligibility screen, and 200 of 285 (70.2%) eligible patients completed a FIT, 27 (13.5%) of whom had a positive result. We share lessons learned about implementing mass screening to encourage further communication among departments of health and corrections to advance preventive health.

Artificial intelligence for non-polypoid colorectal neoplasms

The miss rate of flat advanced colorectal neoplasia is still unacceptably high, especially in the Western setting, notwithstanding the widespread implementation of quality improvement programs and training. It is well known that flat morphology is associated with miss rate of colorectal neoplasia, and that this subset of lesions often shows a more aggressive biological behaviour. Artificial intelligence (AI) applied to the detection of colorectal neoplasia has been shown to increase adenoma detection rate, consistently across all lesion sizes and locations in the colon. However, there is still uncertainty whether AI can reduce the miss rate of flat advanced neoplasia, mainly because all published trials report a low number of flat colorectal lesions in their training sets, and this could reduce AI accuracy for this subset of lesions. In addition, flat lesions have different morphologies with variable prevalence and potentially different accuracy in their detection. For example, the subtle appearance and rarer frequency of a non-granular laterally spreading tumor (LST) could be much harder to identify than a granular mixed LST. In this review, we present a summary of the evidence on the role of AI in the identification of colorectal flat neoplasia, with a focus on data regarding presence of LSTs in the training/validation sets of the AI systems currently available on the market.