Rationalizing polyp matching criteria in colon capsule endoscopy: an international expert consensus through RAND (modified DELPHI) process.

Background: Colon capsule endoscopy (CCE) has gained momentum as an alternative modality for the investigation of the lower gastrointestinal tract. Of the few challenges that remain, the comparison and - eventually - matching of polyps at different timestamps leads to the potential for double reporting and can contribute to false-positive findings and inaccuracies. With the impending artificial intelligence integration, the risk of double reporting the same polyp due to the lack of information on spatial orientation underscores the necessity for establishing criteria for polyp matching. Objectives: This RAND/University of California, Los Angeles (modified Delphi) process aims to identify the key factors or components used to match polyps within a CCE video. This involves exploring the attributes of each factor to create comprehensive polyp-matching criteria based on international expert consensus. Design: A systematic qualitative study using surveys. Methods: A panel of 11 international CCE experts convened to assess a survey comprised of 60 statements. Participants anonymously rated statement appropriateness on a 1-9 scale (1-3: inappropriate, 4-6: uncertain and 7-9: appropriate). Following a virtual group discussion of the Round 1 results, a Round 2 survey was developed and completed before the final analysis. Results: The factors that were agreed to be essential for polyp matching include (1) timestamp, (2) polyp localization, (3) polyp vascular pattern, (4) polyp size, (5) time interval of the polyp appearance between the green and yellow camera, (6) surrounding tissue, (7) polyp morphology and (8) polyp surface and contour. When five or more factors are satisfied, it was agreed that the comparing polyps are likely the same polyp. Conclusion: This study has established the first complete criteria for polyp matching in CCE. While it might not provide a definitive solution for matching difficult, small and common polyps, these criteria serve as a framework to guide and facilitate the process of polyp-matching.

Creating criteria and standards for matching polyps (abnormal growth in the bowels) on colon capsule video analysis: an international expert agreement using the RAND (modified Delphi process) process Background: Doctors often use colon capsule endoscopy (CCE), a high-tech capsule with two cameras, to record and check for diseases in the small and large bowels as the capsule travels through the intestines. One of the most common conditions in the large bowel is polyps, which are abnormal growths in the lining of the bowel. Comparing and matching polyps in the same video from the capsule can be tricky as they look very similar, leading to the possibility of incorrectly reporting the same polyp twice or more. This can lead to wrong results and inaccuracies. The literature did not have any criteria or standards for matching polyps in CCE before. Aim: Using the RAND/UCLA (modified Delphi) process, this study aims to identify the key factors or components used to match polyps within a CCE video. The goal is to explore each factor and create complete criteria for polyp matching based on the agreement from international experts. Method: A group of 11 international CCE experts came together to evaluate a survey with 60 statements. They anonymously rated each statement on a scale from 1 to 9 (1-3: inappropriate, 4-6: uncertain, and 7-9: appropriate). After discussing the Round 1 results virtually, a Round 2 survey with the same but revised questions was created and completed before the final analysis of their agreement. Results: The main factors for matching polyps are 1) the timing when the polyp was seen, 2) where it is in the bowel, 3) its blood vessel pattern, 4) size, 5) the timing of its appearance between cameras, 6) surrounding tissue features, 7) its shape, and 8) surface features. If five or more of these factors match, the compared polyps are likely the same. Conclusion: This study establishes the first complete criteria for matching polyps in CCE. While it may not provide a definitive solution for matching challenging and small polyps, these criteria serve as a guide to help and make the process of polyp matching easier.

AI-assisted capsule endoscopy reading in suspected small bowel bleeding: a multicentre prospective study.

BACKGROUND: Capsule endoscopy reading is time consuming, and readers are required to maintain attention so as not to miss significant findings. Deep convolutional neural networks can recognise relevant findings, possibly exceeding human performances and reducing the reading time of capsule endoscopy. Our primary aim was to assess the non-inferiority of artificial intelligence (AI)-assisted reading versus standard reading for potentially small bowel bleeding lesions (high P2, moderate P1; Saurin classification) at per-patient analysis. The mean reading time in both reading modalities was evaluated among the secondary endpoints. METHODS: Patients aged 18 years or older with suspected small bowel bleeding (with anaemia with or without melena or haematochezia, and negative bidirectional endoscopy) were prospectively enrolled at 14 European centres. Patients underwent small bowel capsule endoscopy with the Navicam SB system (Ankon, China), which is provided with a deep neural network-based AI system (ProScan) for automatic detection of lesions. Initial reading was performed in standard reading mode. Second blinded reading was performed with AI assistance (the AI operated a first-automated reading, and only AI-selected images were assessed by human readers). The primary endpoint was to assess the non-inferiority of AI-assisted reading versus standard reading in the detection (diagnostic yield) of potentially small bowel bleeding P1 and P2 lesions in a per-patient analysis. This study is registered with ClinicalTrials.gov, NCT04821349. FINDINGS: From Feb 17, 2021 to Dec 29, 2021, 137 patients were prospectively enrolled. 133 patients were included in the final analysis (73 [55%] female, mean age 66·5 years [SD 14·4]; 112 [84%] completed capsule endoscopy). At per-patient analysis, the diagnostic yield of P1 and P2 lesions in AI-assisted reading (98 [73·7%] of 133 lesions) was non-inferior (p<0·0001) and superior (p=0·0213) to standard reading (82 [62·4%] of 133; 95% CI 3·6-19·0). Mean small bowel reading time was 33·7 min (SD 22·9) in standard reading and 3·8 min (3·3) in AI-assisted reading (p<0·0001). INTERPRETATION: AI-assisted reading might provide more accurate and faster detection of clinically relevant small bowel bleeding lesions than standard reading. FUNDING: ANKON Technologies, China and AnX Robotica, USA provided the NaviCam SB system.

Development and content validity testing of a colonoscopy-specific patient-reported experience measure: the Patient Experience Colonoscopy Scale (PECS).

BACKGROUND: In endoscopic care, favourable patient experiences before, during and after a colonoscopy are essential for the patient's willingness to repeat the procedure. To ensure that significant experiences are measured, patients should be involved in creating the measurement instruments. Thus, the aim of the present study was to develop a colonoscopy-specific PREM by (1) operationalising patient experiences before, during and after a colonoscopy procedure and (2) evaluating its content validity. METHODS: The colonoscopy-specific PREM was developed in two stages: (1) operationalisation with item generation and (2) content validity testing. A previously developed conceptual model, based on a systematic literature review that illustrates patients' (n = 245) experiences of undergoing a colonoscopy, formed the theoretical basis. To assess the degree to which the PREM reflected patients' experiences before, during and after a colonoscopy procedure, content validity was tested-through face validity with healthcare professionals (n = 4) and cognitive interviews with patients (n = 14) having experienced a colonoscopy. Content validity index (CVI) was calculated to investigate the relevance of the items. RESULTS: The Patient Experience Colonoscopy Scale (PECS) is a colonoscopy-specific PREM consisting of five different constructs: health motivation, discomfort, information, a caring relationship and understanding. Each construct was defined and generated into a pool of items (n = 77). After face-validity assessment with healthcare professionals, a draft 52-item version of the PECS was ready for content validity testing by the patients. During cognitive interviews the patients contributed valuable insights that led to rewording and removal of items. Results from the CVI suggest that the PECS and its content are relevant (I-CVI range 0.5-1, S-CVI/Ave = 0.86). The final PECS consists of 30 items representing a colonoscopy-specific PREM. CONCLUSION: The PECS is a new 30-item PREM instrument designed for adult elective colonoscopy patients after they have undergone the procedure. Each item in the PECS derives from a conceptual model based on a systematic literature review. Patients and healthcare professionals were involved in developing the PECS, which measures colonoscopy-specific patient experiences before, during and after the procedure. The content validity testing positively contributed to the development of the PECS. Psychometric properties need to be evaluated further.

Assessing Patient Radiation Exposure in Endoscopic Retrograde Cholangiopancreatography: A Multicenter Retrospective Analysis of Procedural Complexity and Clinical Factors.

BACKGROUND AND AIMS: Endoscopic retrograde cholangiopancreatography (ERCP) procedures can result in significant patient radiation exposure. This retrospective multicenter study aimed to assess the influence of procedural complexity and other clinical factors on radiation exposure in ERCP. METHODS: Data on kerma-area product (KAP), air-kerma at the reference point (Ka,r), fluoroscopy time, and the number of exposures, and relevant patient, procedure, and operator factors were collected from 2641 ERCP procedures performed at four university hospitals. The influence of procedural complexity, assessed using the American Society for Gastrointestinal Endoscopy (ASGE) and HOUSE complexity grading scales, on radiation exposure quantities was analyzed within each center. The procedures were categorized into two groups based on ERCP indications: primary sclerosing cholangitis (PSC) and other ERCPs. RESULTS: Both the ASGE and HOUSE complexity grading scales had a significant impact on radiation exposure quantities. Remarkably, there was up to a 50-fold difference in dose quantities observed across the participating centers. For non-PSC ERCP procedures, the median KAP ranged from 0.9 to 64.4 Gy·cm2 among the centers. The individual endoscopist also had a substantial influence on radiation dose. CONCLUSIONS: Procedural complexity grading in ERCP significantly affects radiation exposure. Higher procedural complexity is typically associated with increased patient radiation dose. The ASGE complexity grading scale demonstrated greater sensitivity to changes in radiation exposure compared to the HOUSE grading scale. Additionally, significant variations in dose indices, fluoroscopy times, and number of exposures were observed across the participating centers.

Endoscopic Gastrointestinal Placement of Capsule Endoscopy to Investigate the Small Bowel: a Multicentric European Retrospective Series of 630 Procedures in Adult Patients.

BACKGROUND AND AIMS: Small bowel (SB) capsule endoscopy (CE) is a first line procedure for exploring the SB. Endoscopic GastroIntestinal PlacemenT (EGIPT) of SB CE is sometimes necessary. While the experience of EGIPT is large in pediatric populations, we aimed to describe the safety, efficacy and outcomes of EGIPT of SB CE in adult patients. METHODS: The international CApsule endoscopy REsearch (iCARE) group set up a retrospective multicenter study. Patients over 18 year-old who underwent EGIPT of SB CE before May 2022 were included. Data were collected from medical records and capsule recordings. The primary endpoint was the technical success rate of the EGIPT procedures. RESULTS: 630 patients were included (mean age 62.5 years old, 55.9% female) from 39,565 patients (1.6%) issued from 29 centers. EGIPT technical success was achieved in 610 procedures (96.8%). Anesthesia (moderate/deep sedation or general anesthesia) and centers with intermediate or high procedure loads were independent factors of technical success. Severe adverse events occurred in three (0.5%) patients. When technically successful, EGIPT was associated with a high SB CE completion rate (84.4%) and with a substantial diagnostic yield (61.1%). Completion rate was significantly higher when the capsule was delivered in the SB compared to when delivered in the stomach. CONCLUSION: EGIPT of SB CE is highly feasible, safe and comes with high completion rate and diagnostic yield. When indicated, it should rather be performed under anesthesia and the capsule should be delivered in the duodenum rather than in the stomach, for better SB examination outcomes.

[A new study raises unexpected questions about colonoscopy as primary screening method]. / Är koloskopi rätt metod för att screena för kolorektalcancer?

Convincing data in the literature demonstrate that screening reduces mortality in colorectal cancer. A recent study (NordICC) randomising nearly 85 000 healthy men and women drawn from population registries in Norway, Poland and Sweden to either colonoscopy or no screening reported 18 % reduction in incidence of colorectal cancer but no effect on mortality at 10-year follow-up. This finding is in contrast to previous randomised studies on sigmoidoscopy and cohort studies on coloscopy showing clear-cut effects on both colorectal cancer incidence and mortality. There could be several explanations for these discrepancies. In the NordICC study, only 42 % of the invited individuals performed a colonoscopy compared to 60-90 % in the other studies. Moreover, the follow-up time was only 10 years, and longer follow-up times will clarify the results better especially considering the fact that the number of colorectal cancer cases increases in the colonoscopy arms during the first year due to detection of presymptomatic cancers. Finally, adenoma detection rate varied a lot and nearly 30 % of the colonoscopists in the NordICC study had an adenoma detection rate below the recommended level of 25 %. Nonetheless, this is an important study that raises critical questions about colonscopy as a primary screening method for colorectal cancer.

Key research questions for implementation of artificial intelligence in capsule endoscopy.

Background: Artificial intelligence (AI) is rapidly infiltrating multiple areas in medicine, with gastrointestinal endoscopy paving the way in both research and clinical applications. Multiple challenges associated with the incorporation of AI in endoscopy are being addressed in recent consensus documents. Objectives: In the current paper, we aimed to map future challenges and areas of research for the incorporation of AI in capsule endoscopy (CE) practice. Design: Modified three-round Delphi consensus online survey. Methods: The study design was based on a modified three-round Delphi consensus online survey distributed to a group of CE and AI experts. Round one aimed to map out key research statements and challenges for the implementation of AI in CE. All queries addressing the same questions were merged into a single issue. The second round aimed to rank all generated questions during round one and to identify the top-ranked statements with the highest total score. Finally, the third round aimed to redistribute and rescore the top-ranked statements. Results: Twenty-one (16 gastroenterologists and 5 data scientists) experts participated in the survey. In the first round, 48 statements divided into seven themes were generated. After scoring all statements and rescoring the top 12, the question of AI use for identification and grading of small bowel pathologies was scored the highest (mean score 9.15), correlation of AI and human expert reading-second (9.05), and real-life feasibility-third (9.0). Conclusion: In summary, our current study points out a roadmap for future challenges and research areas on our way to fully incorporating AI in CE reading.

[Updated Swedish guidelines for endoscopic surveillance after colorectal polypectomy]. / Nya riktlinjer: endoskopisk kontroll efter kolorektal polypektomi.

These new guidelines are based on the recommendations published by European Society of Gastrointestinal Endoscopy (ESGE) in 2020. Low risk patients, i.e. after removal of 1-4 <10 mm adenomas with low grade dysplasia (irrespective of villous components), or any serrated lesion (hyperplastic polyp, sessile serrated lesion, or traditional serrated adenoma) <10 mm without dysplasia, are not recommended a surveillance colonoscopy. High-risk patients, i.e. after removal of at least one adenoma ≥10 mm or with high grade dysplasia or any serrated lesion ≥10 mm or with dysplasia, should undergo a surveillance colonoscopy after 3 years. If high-risk lesions are detected at surveillance colonoscopy, a 3-year repetition of the next endoscopic examination is recommended. If a high-risk patient has no high-risk lesions at surveillance colonoscopy, a 5-year period is recommended until the next surveillance colonoscopy. In general, follow-up should be terminated at 80 years of age.

Inter/Intra-Observer Agreement in Video-Capsule Endoscopy: Are We Getting It All Wrong? A Systematic Review and Meta-Analysis.

Video-capsule endoscopy (VCE) reading is a time- and energy-consuming task. Agreement on findings between readers (either different or the same) is a crucial point for increasing performance and providing valid reports. The aim of this systematic review with meta-analysis is to provide an evaluation of inter/intra-observer agreement in VCE reading. A systematic literature search in PubMed, Embase and Web of Science was performed throughout September 2022. The degree of observer agreement, expressed with different test statistics, was extracted. As different statistics are not directly comparable, our analyses were stratified by type of test statistics, dividing them in groups of "None/Poor/Minimal", "Moderate/Weak/Fair", "Good/Excellent/Strong" and "Perfect/Almost perfect" to report the proportions of each. In total, 60 studies were included in the analysis, with a total of 579 comparisons. The quality of included studies, assessed with the MINORS score, was sufficient in 52/60 studies. The most common test statistics were the Kappa statistics for categorical outcomes (424 comparisons) and the intra-class correlation coefficient (ICC) for continuous outcomes (73 comparisons). In the overall comparison of inter-observer agreement, only 23% were evaluated as "good" or "perfect"; for intra-observer agreement, this was the case in 36%. Sources of heterogeneity (high, I2 81.8-98.1%) were investigated with meta-regressions, showing a possible role of country, capsule type and year of publication in Kappa inter-observer agreement. VCE reading suffers from substantial heterogeneity and sub-optimal agreement in both inter- and intra-observer evaluation. Artificial-intelligence-based tools and the adoption of a unified terminology may progressively enhance levels of agreement in VCE reading.

Nomenclature and Definition of Atrophic Lesions in Small Bowel Capsule Endoscopy: A Delphi Consensus Statement of the International CApsule endoscopy REsearch (I-CARE) Group.

(1) Background: Villous atrophy is an indication for small bowel capsule endoscopy (SBCE). However, SBCE findings are not described uniformly and atrophic features are sometimes not recognized; (2) Methods: The Delphi technique was employed to reach agreement among a panel of SBCE experts. The nomenclature and definitions of SBCE lesions suggesting the presence of atrophy were decided in a core group of 10 experts. Four images of each lesion were chosen from a large SBCE database and agreement on the correspondence between the picture and the definition was evaluated using the Delphi method in a broadened group of 36 experts. All images corresponded to histologically proven mucosal atrophy; (3) Results: Four types of atrophic lesions were identified: mosaicism, scalloping, folds reduction, and granular mucosa. The core group succeeded in reaching agreement on the nomenclature and the descriptions of these items. Consensus in matching the agreed definitions for the proposed set of images was met for mosaicism (88.9% in the first round), scalloping (97.2% in the first round), and folds reduction (94.4% in the first round), but granular mucosa failed to achieve consensus (75.0% in the third round); (4) Conclusions: Consensus among SBCE experts on atrophic lesions was met for the first time. Mosaicism, scalloping, and folds reduction are the most reliable signs, while the description of granular mucosa remains uncertain.

Indications, Detection, Completion and Retention Rates of Capsule Endoscopy in Two Decades of Use: A Systematic Review and Meta-Analysis.

BACKGROUND: Capsule endoscopy (CE) has become a widespread modality for non-invasive evaluation of the gastrointestinal (GI) tract, with several CE models having been developed throughout the years. The aim of this systematic review and meta-analysis is to evaluate performance measures such as completion, detection and retention rates of CE. METHODS: Literature through to August 2021 was screened for articles regarding all capsule types: small bowel, double-headed capsule for the colon or PillCam®Crohn's capsule, magnetically-controlled capsule endoscopy, esophageal capsule and patency capsule. Primary outcomes included detection rate (DR), completion rate (CR) and capsule retention rate (RR). DR, CR and RR were also analyzed in relation to indications such as obscure GI bleeding (OGIB), known/suspected Crohn's disease (CD), celiac disease (CeD), neoplastic lesions (NL) and clinical symptoms (CS). RESULTS: 328 original articles involving 86,930 patients who underwent CE were included. OGIB was the most common indication (n = 44,750), followed by CS (n = 17,897), CD (n = 11,299), NL (n = 4989) and CeD (n = 947). The most used capsule type was small bowel CE in 236 studies. DR, CR and RR for all indications were 59%, 89.6% and 2%, respectively. According to specific indications: DR were 55%, 66%, 63%, 52% and 62%; CR were 90.6%, 86.5%, 78.2%, 94% and 92.8%; and RR were 2%, 4%, 1%, 6% and 2%. CONCLUSIONS: Pooled DR, CR and RR are acceptable for all capsule types. OGIB is the most common indication for CE. Technological advancements have expanded the scope of CE devices in detecting GI pathology with acceptable rates for a complete examination.

The Effectiveness and Tolerability of a Very Low-Volume Bowel Preparation for Colonoscopy Compared to Low and High-Volume Polyethylene Glycol-Solutions in the Real-Life Setting.

Adequate bowel cleansing is essential for high-quality colonoscopy. Recently, a new very low-volume 1 litre (1L) polyethylene glycol (PEG) plus ascorbate solution (ASC) has been introduced. Our aims were to assess the effectiveness and tolerability of this product compared to low-volume 2L PEG-ASC and high-volume 4L PEG solutions, in a real-life setting. In six endoscopy units in Sweden, outpatients undergoing colonoscopy were either prescribed solutions according to local routines, or the very low-volume solution in split dose regimen. Bowel cleansing effectiveness and patient experience was assessed using the Boston Bowel preparation scale (BBPS) and a patient questionnaire. A total of 1098 patients (mean age 58 years, 52% women) were included. All subsegment and the total BBPS scores were significantly greater for 1L PEG-ASC in comparison to other solutions (p < 0.05 for 1L PEG-ASC and 4L PEG for transverse and left colon, otherwise p < 0.001). Nausea was more frequent with 1L PEG-ASC compared to 2L PEG-ASC (p < 0.001) and vomiting were more often reported compared to both other solutions (p < 0.01 and p < 0.05 for 2L PEG-ASC and 4L PEG, respectively). Smell, taste, and total experience was better for 1L PEG-ASC compared to 4L PEG (p < 0.001), and similar compared to the 2L PEG-ASC. In conclusion, 1L PEG-ASC leads to better bowel cleansing compared to 2L PEG-ASC or 4L PEG products, with similar or greater patient satisfaction.

Erratum: Real-life practice data on colon capsule endoscopy: We need them fast!

[This corrects the article DOI: 10.1055/a-1728-9371.].

Factors Associated with Polyp Detection Rate in European Colonoscopy Practice: Findings of The European Colonoscopy Quality Investigation (ECQI) Group.

Background: The European Colonoscopy Quality Investigation (ECQI) Group aims to raise awareness for improvement in colonoscopy standards across Europe. We analysed data collected on a sample of procedures conducted across Europe to evaluate the achievement of the polyp detection rate (PDR) target. We also investigated factors associated with PDR, in the hope of establishing areas that could lead to a quality improvement. Methods: 6445 form completions from 12 countries between 2 June 2016 and 30 April 2018 were considered for this analysis. We performed an exploratory analysis looking at PDR according to European Society of Gastrointestinal Endoscopy (ESGE) definition. Stepwise multivariable logistic regression analysis was conducted to determine the most influential associated factors after adjusting for the other pre-specified variables. Results: In our sample there were 3365 screening and diagnostic procedures performed in those over 50 years. The PDR was 40.5%, which is comparable with the ESGE minimum standard of 40%. The variables found to be associated with PDR were in descending order: use of high-definition equipment, body mass index (BMI), patient gender, age group, and the reason for the procedure. Use of HD equipment was associated with a significant increase in the reporting of flat lesions (14.3% vs. 5.7%, p < 0.0001) and protruded lesions (34.7% vs. 25.4%, p < 0.0001). Conclusions: On average, the sample of European practice captured by the ECQI survey meets the minimum PDR standard set by the ESGE. Our findings support the ESGE recommendation for routine use of HD colonoscopy.

Patient-Reported Experience Measures for Colonoscopy: A Systematic Review and Meta-Ethnography.

Patient experience is defined as a major quality indicator that should be routinely measured during and after a colonoscopy, according to current ESGE guidelines. There is no standard approach measuring patient experience after the procedure and the comparative performance of the different colonoscopy-specific patient-reported experience measures (PREMs) is unclear. Therefore, the aim was to develop a conceptual model describing how patients experience a colonoscopy, and to compare the model against colonoscopy-specific PREMs. A systematic search for qualitative research published up to December 2021 in PubMed, Cochrane, CINAHL, and PsycINFO was conducted. After screening and quality assessment, data from 13 studies were synthesised using meta-ethnography. Similarities and differences between the model and colonoscopy-specific PREMs were identified. A model consisting of five concepts describes how patients experience undergoing a colonoscopy: health motivation, discomfort, information, a caring relationship, and understanding. These concepts were compared with existing PREMs and the result shows that there is agreement between the model and existing PREMs for colonoscopy in some parts, while partial agreement or no agreement is present in others. These findings suggest that new PREMs for colonoscopy should be developed, since none of the existing colonoscopy-specific PREMs fully cover patients' experiences.

Factors Associated with Withdrawal Time in European Colonoscopy Practice: Findings of the European Colonoscopy Quality Investigation (ECQI) Group.

The European Colonoscopy Quality Investigation (ECQI) Group aims to raise awareness for improvement in colonoscopy standards across Europe. We analyzed data collected on a sample of procedures conducted across Europe to evaluate the achievement of the European Society of Gastrointestinal Endoscopy (ESGE) mean withdrawal time (WT) target. We also investigated factors associated with WT, in the hope of establishing areas that could lead to a quality improvement. METHODS: 6445 form completions from 12 countries between 2 June 2016 and 30 April 2018 were considered for this analysis. We performed an exploratory analysis looking at WT according to the ESGE definition. Stepwise multivariable logistic regression analysis was conducted to determine the most influential associated factors after adjusting for the other pre-specified variables. RESULTS: In 1150 qualifying colonoscopies, the mean WT was 7.8 min. Stepwise analysis, including 587 procedures where all inputs were known, found that the variables most associated with mean WT were a previous total colonoscopy in the last five years (p = 0.0011) and the time of day the colonoscopy was performed (p = 0.0192). The main factor associated with a WT < 6 min was the time of day that a colonoscopy was performed. Use of sedation was the main factor associated with a higher proportion of WT > 10 min, along with a previous colonoscopy. CONCLUSIONS: On average, the sample of European practice captured by the ECQI survey met the minimum standard set by the ESGE. However, there was variation and potential for improvement.

Lymphovascular Infiltration, Not Depth of Invasion, is the Critical Risk Factor of Metastases in Early Colorectal Cancer: Retrospective Population-based Cohort Study on Prospectively Collected Data, Including Validation.

OBJECTIVE: To identify clinical and histopathological risk factors of LNM in T1 CRC. SUMMARY OF BACKGROUND DATA: The requisite of additional surgery after locally resected T1 CRC is dependent on the risk of LNM. Depth of submucosal invasion is used as a key predictor of lymphatic metastases although data are conflicting on its actual impact. METHODS: Retrospective population-based cohort study on prospectively collected data on all patients with T1 CRC undergoing surgical resection in Sweden, 2009-2017 and Denmark 2016-2018. The Danish cohort was used for validation. Potential risk factors of LNM investigated were; age, sex, tumor location, submucosal invasion, grade of differentiation, mucinous subtype, lymphovascular, and perineural invasion. RESULTS: One hundred fifty out of the 1439 included patients (10%) had LNM. LVI (P < 0.001), perineural invasion (P < 0.001), mucinous subtype (P = 0.006), and age <60 years (P < 0.001) were identified as independent risk factors whereas deep submucosal invasion was only a dependent (P = 0.025) risk factor and not significant in multivariate analysis (P = 0.075). The incidence of LNM was 51/882 (6%) in absence of the independent risk factors. The Danish validation cohort, confirmed our findings regarding the role of submucosal invasion, LVI, and age. CONCLUSIONS: This is a large study on LNM in T1 CRC, including validation, showing that LVI and perineural invasion, mucinous subtype, and low age constitute independent risk factors, whereas depth of submucosal invasion is not an independent risk factor of LNM. Thus, our findings provide a useful basis for management of patients after local excision of early CRC.