Low-fiber Diet for Colorectal Cancer Screening Colonoscopy

Study Overview
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Brief Summary
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This trial will compare the efficacy of 2 different sets of dietary recommendations to be followed before colon cleansing for colorectal cancer screening colonoscopy.

Detailed Description
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There is no enough evidence in the literature to recommend a low-fiber diet for screening colonoscopy. Although evidence of benefit of a liquid diet is minimal and there is a growing body of evidence about the benefits of a liberalized diet, a high degree of heterogeneity in the clinical trials comparing the diet modifications before colonoscopy prevents a formal recommendation in current guidelines. A low-fiber diet the day before colonoscopy may result in same efficacy of bowel cleanliness, with an improved tolerability and acceptability. All consecutive patients of a population-based colorectal screening cancer program referred for a colonoscopy will be invited to participate in the study. After obtaining informed consent, they will be randomized to one of the groups: liquid diet or low-fiber diet. The will be interviewed by a registered research nurse, and they will be provided with written instructions for bowel preparation and questionnaires for registering the data of the study. The day of the colonoscopy, questionnaires will be collected and endoscopists blinded for the study bowel preparation will perform the colonoscopy. Patients will be contacted for adverse events and a general satisfaction questionnaire, 3 days after colonoscopy.

Official Title
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Low-fiber Diet for Colorectal Cancer Screening Colonoscopy. Randomized Clinical Trial. Dietcol Study

Conditions
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Colonic Diseases

Intervention / Treatment
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* Dietary Supplement: Low-residue diet
* Dietary Supplement: Usual care


Participation Criteria
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Eligibility Criteria
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Inclusion criteria: Consecutive patients referred for a colonoscopy in a population-based colorectal screening program. Exclusion criteria: Unwillingness to participate. Inability to follow instructions Active inflammatory bowel disease Incomplete colonoscopies for technical reasons or contraindication as evaluated by the endoscopist

Ages Eligible for Study
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Minimum Age: 18 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: Supportive Care
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Low-residue diet<br>The experimental group will receive 4 days of low-residue diet Laxative 4 liters polyethylene glycol 4000 in split fashion. | Dietary Supplement: Low-residue diet<br>* Subjects will be instructed by members of the research team to follow a standardized low residue diet for 4 days<br>|
| Active Comparator: Usual care<br>The control group will receive 3 days of low-residue diet followed by 24 hours of liquid diet. Laxative 4 liters polyethylene glycol 4000 in split fashion. | Dietary Supplement: Usual care<br>* Subjects will be instructed by members of the research team to follow a low-residue diet for 3 days followed by 24 hours of liquid diet<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Inadequate bowel preparation. | The efficacy of bowel preparation will be rated by blinded endoscopists using the Boston Bowel Preparation Scale (BBPS). Colonoscopies with a BBPS score of less than 5 points, or any segment rated less than 2 points will be considered with an inadequate bowel preparation | 1 hour after the colonoscopy | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Cecal intubation rate | Ratio of successful cecal intubations in each study arm | 1 hour after the colonoscopy | 
| Adenoma detection rate | Ratio of polyps and adenomas detected in each study arm | 1 hour after the colonoscopy | 
| Polyp detection rate | Ratio of polyps and adenomas detected in each study arm | 1 hour after the colonoscopy | 
| Abdominal pain | Each participant will rate his/her experience in an analogue visual scale | 6 hours after finishing bowel preparation | 
| Nausea | Each participant will rate his/her experience in an analogue visual scale | 6 hours after finishing bowel preparation | 
| Hunger | Each participant will rate his/her experience in an analogue visual scale | 6 hours after finishing bowel preparation | 
| Bloating | Each participant will rate his/her experience in an analogue visual scale | 6 hours after finishing bowel preparation | 
| Adverse events | Description of all spontaneously reported adverse events. | 30 days after the colonoscopy | 
| Adherence to the planned bowel cleansing method (questionnaire) | Each participant will rate his/her experience in a questionnaire. | 6 hours after finishing bowel preparation | 
| Acceptability of the preparation (interference with work, leisure activities or sleep | Each participant will rate his/her experience in a questionnaire. | 6 hours after finishing bowel preparation | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Colonoscopy, Diet, Polyethylene glycols, Efficacy, Personal satisfaction, Colorectal cancer screening