Implementation of Optical Diagnosis for Diminutive Polyps Amongst Endoscopists: Training and Long-term Quality Assurance

Study Overview
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Brief Summary
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In this study, Dutch gastroenterologists who are certified for performing colonoscopies on FIT-positive patients in the Dutch population screening program are trained in optical diagnosis with validated methods. After this training, an ex- and in-vivo test phase leads to accreditation and endoscopists will be observed in their optical diagnosis for 1 year. During this year, half of the endoscopists will be randomized towards 3-monthly feedback and the other half will receive feedback on their results after 1 year. The endoscopic prediction of endoscopists on polyp histology will be compared to histopathological outcome.

Detailed Description
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Through the recently started nationwide bowel cancer screening programme in the Netherlands, an extra 70.000 colonoscopies are annually performed. In current practice, all resected colonic lesions are histopathologically analysed. Even diminutive polyps, which rarely harbour cancer or advanced histological features. If endoscopists are able to accurately differentiate between neoplastic and non-neoplastic lesions during colonoscopy, practice could become more efficient and costeffective. This strategy is called optical diagnosis and two clinical practice strategies have been proposed by the American Society of Gastroenterologists (ASGE). First, diminutive polyps could be resected and discarded if >90% of the surveillance intervals predicted on optical diagnosis correlate with the surveillance intervals after histopathological validation (if assessed with high confidence). Second, hyperplastic polyps in the rectosigmoid could be left in situ if endoscopists are able to confidently predict neoplastic histology of diminutive colorectal polyps with a negative predictive value (NPV) of ≥90%. The accuracy of white light colonoscopy is not acceptable for daily practice (59%-84%), but narrow band imaging (NBI) allows higher accuracies up to 98% and it was demonstrated that experienced endoscopists could reach a NPV of ≥90% for diminutive colorectal lesions. However, recent research shows that community gastroenterologists are not able to meet the quality thresholds proposed by the ASGE. Before this strategy could be safely applied in daily practice, community gastroenterologists should be able to meet thresholds as well. In this study, Dutch gastroenterologists who are certified for performing colonoscopies on FIT-positive patients in the Dutch population screening program, are trained in optical diagnosis with validated methods. After training, an ex- and in-vivo test phase leads to accreditation and endoscopists will be observed in their optical diagnosis for 1 year. During this year, half of the endoscopists will be randomized towards 3-monthly feedback and the other half will receive feedback on their results after 1 year. The endoscopic prediction of endoscopists on polyp histology will be compared to histopathological outcome.

Official Title
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Implementation of Optical Diagnosis for Diminutive Polyps Amongst Accredited Endoscopists for the Dutch Bowel Cancer Screening Program: Training and Long-term Quality Assurance

Conditions
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Colonoscopy, Colonic Polyps

Intervention / Treatment
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* Behavioral: Feedback


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Colonoscopies performed in FIT positive patients obtained for the Dutch colorectal cancer screening program. Exclusion Criteria: Colonoscopies in patients with a history of colorectal cancer, inflammatory bowel disease or polyposis syndrome. Colonoscopies in patients with bleeding disorders or anticoagulants and therefore cannot undergo polypectomy.

Ages Eligible for Study
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Minimum Age: 55 Years
Maximum Age: 75 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Endoscopists<br>Approximately 35 endoscopists whom are certified to perform colonoscopies on FIT-positive patients in the Dutch population screening program | Behavioral: Feedback<br>* 3-monthly or no 3-monthly feedback on results of optical diagnosis<br>|
| Colonoscopies<br>Colonoscopies on FIT-positive patients in the Dutch population screening program | |
| Device<br>Olympus colonoscopes with Narrow Band Imaging | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| the number of training rounds needed until endoscopists reach a clinical acceptable accuracy of predicting histology of subcentimetric (1-9 mm) colorectal lesions using NBI |  | 18 months | 
| the number of qualified endoscopists that are able to maintain a clinical acceptable accuracy of predicting histology of subcentimetric (1-9 mm) colorectal lesions using NBI over a year, either with and without regular interim feedback. |  | 18 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| the number of the accredited endoscopists that is able to reach a negative predictive value of at least 90% for predicting neoplastic diminutive (1-5mm) and small (6-9mm) colorectal lesions in the rectosigmoid |  | 18 months | 
| the number of diminutive (1-5mm) and small (6-9mm) lesions that are correctly predicted with high confidence |  | 18 months | 
| the number of patients in whom a surveillance interval (according to the Dutch surveillance guideline) can be advised directly after colonoscopy, based on the endoscopic diagnosis |  | 18 months | 
| the number of patients in whom the surveillance interval (according to the Dutch surveillance guideline) is correctly predicted based on endoscopic diagnosis |  | 18 months | 
| the number of correctly diagnosed sessile serrated adenoma/polyps in diminutive (1-5mm) and small (6-9mm) polyps |  | 18 months | 
| the sensitivity for predicting neoplastic histology per endoscopist, time frame and feedback or no feedback group |  | 18 months | 
| the costs in euros that would have been saved by multiplying the amount of high confidence predicted diminutive and small polyps with the histopathology costs per lesion |  | 18 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Optical diagnosis