Can Pan-Colonic Chromoendoscopy (PCC) Improve Adenoma Detection Rate in FIT-Positive-Patients: A Randomized Study

Study Overview
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Brief Summary
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Colonoscopy is the technique of choice for evaluation of patients with positive fecal occult blood (FIT). Identification of polyps and their removal has been shown to decrease colorectal cancer incidence rates and mortality. Many endoscopic imaging technologies and devices have been developed to increase adenoma detection (ADR) during screening colonoscopies. They vary in the way they work, and some of the technologies are costly and not widely available. Studies has shown the simple to use pan-colonic chromoendoscopy can improve ADR compared to standard colonoscopy. However, there is little evidence on the utility of pan-colonic chromoendoscopy in asymptomatic individuals undergoing colonoscopy after a positive FIT test. In this randomized study, the investigators aim to compare the utility of chromoendoscopy and high-definition white-light endoscopy in asymptomatic individuals undergoing colonoscopy after a positive FIT test

Detailed Description
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Eligible subjects with positive screening FIT test referred to the Department of Gastroenterology, Singapore General Hospital will be approached and recruited. The included patients will be randomised to either a) Group A- Chromoendoscopy or b) Group B- high definition white light based evaluation. Hypothesis: The investigators hypothesize that application of non-absorbable dye during colonoscopy would enhance the mucosal contrast, delineate the border and surface patterns by accumulating in the innominate grooves and, thereby, enhance the detection of adenoma during colonoscopy Procedure: Pan-colonic chromoendoscopy and high-definition white light endoscopy will be performed by five experienced endoscopist, and hospital sedation guidelines will be followed. The colonoscopy will be performed using Olympus (CF-HQ190) or Fujifilm (EC-590) colonoscopies. Indigo carmine dye will be used for pan-colonic chromoendoscopy. Two ampules of Indigo carmine (0.8%, 5ml/ampule) will be dissolved in 250 ml of water and sprayed through the waterjet channel by using the auxiliary foot pump upon reaching the caecum. The colonoscopy insertion will be performed using high-definition white light, and the scope will be advanced till the caecum. The quality of the bowel preparation will be rated according to the validated Boston bowel preparation score. Participants with inadequate bowel preparation score (Score <6) will be excluded from the study. The fecal residue will be washed, suctioned and cleared during insertion to improve visibility. No special care will be taken to look for lesions during the insertion. Assessment for colonic lesions will only be performed during withdrawal of the endoscope. The minimum withdrawal time was set at 7 minutes. Randomization: Once the caecum is intubated and if the bowel preparation is adequate, the participants will be randomized to pan-colonic chromoendoscopy based withdrawal or high-definition while light based withdrawal. In the pan-colonic chromoendoscopy group, the indigo carmine was sprayed by pressing the auxiliary foot pump, and dye was delivered systematically to coat the entire colonic mucosa. In both, the groups, the lesion size, number, location, morphology will be documented during withdrawal. The investigators characterized the morphology of the lesion according to the established Paris classification. The investigators characterized the lesion as flat neoplasm if the lesion project <2.5mm or polypoid lesion if lesion project >2.5mm into the lumen. The investigators measured the size of the lesions using an open biopsy forceps when needed. In both the groups, the identified polyps will be removed using the standard techniques, and the tissue will be placed in separate formalin bottles and sent for histology assessment. The histology of the polyps was assessed by dedicated pathologist trained in gastrointestinal pathology. Both the endoscopists and the pathologist will not be blinded to the study technique. The investigators defined advanced adenoma as any adenoma >10 mm in size or with >25% villous histology or high-grade dysplasia. The investigators classified hyperplastic polyps and sessile serrated polyps (SSA) as serrated lesions, The investigators excluded hyperplastic lesions in the rectum from the analysis as such lesions are frequently encountered in the rectum

Official Title
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Can Pan-Colonic Chromoendoscopy (PCC) Improve Adenoma Detection Rate in FIT-Positive-Patients: A Randomized Study

Conditions
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Colon Adenoma

Intervention / Treatment
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* Diagnostic Test: Chromoendoscopy
* Diagnostic Test: High definition white light colonoscopy


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age older than 50 years Positive stool FIT test or FOBT test Exclusion Criteria: Known inflammatory bowel disease Known polyposis syndromes Previous history of colon cancer and surgical resection Overt gastrointestinal bleeding Stool FIT or FOBT test performed during hospitalization Inadequate bowel preparation (Boston Bowel Preparation score <6 or <2 for each colonic segment) Poor patient tolerance to the procedure Pregnancy Concurrent intake of anticoagulants and thienopyridines (e.g., Clopidogrel), where these drugs cannot be suspended for the adequate duration before colonoscopy Patient with known history of hypersensitivity to Indigo carmine dye

Ages Eligible for Study
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Minimum Age: 50 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: The participants will be randomised to one of the two groups. The first group will undergo colonoscopy evaluation using pan-colonic chromoendoscopy during withdrawal of endoscope. In the second group, colonoscopy evaluation will be performed using high-definition white light endoscopy during withdrawal
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Dye based Chromoendoscopy<br>The patients enrolled in this group will undergo pan-colonic chromoendoscopy evaluation. | Diagnostic Test: Chromoendoscopy<br>* Participants randomised to Group A will undergo colonoscopic evaluation using dye-based chromoendoscopy<br>|
| Active Comparator: High Definition White Light Endoscopy<br>The patients enrolled in this group will undergo high definition white light endoscopy based evaluation | Diagnostic Test: High definition white light colonoscopy<br>* Participants randomised to Group B will undergo colonoscopic evaluation using high definition white light endoscopy<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| To evaluate the adenoma detection rate between pan-colonic chromoendoscopy and white light colonoscopy |  | 2 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Advanced adenoma detection rate white light colonoscopy |  | 2 years | 
| Flat lesion detection rate |  | 2 years | 
| Serrated adenoma detection rate |  | 2 years | 
| Withdrawal time comparison |  | 2 years | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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FIT- positive, Chromoendoscopy, white light endoscopy, adenoma detection rate, advanced adenoma rate, serrated adenoma rate