Benign Colorectal NeoplasmNCT05643859
Impact of Dietary Fiber Supplementation on Colonic Microbiome
A study testing Dietary Fiber, Proctoscopy or anoscopy with Biopsy and Colonoscopy in people with Benign Colorectal Neoplasm and Non-Neoplastic Anal Disorder, run by OHSU Knight Cancer Institute at 1 site in United States.
Trial summary
This clinical trial tests whether daily fiber supplementation will change the mucosal microbiome of the colon. The microbiome are microorganisms that live in the human gut. They serve a vital role in maintaining health. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Benign Colorectal Neoplasm, Non-Neoplastic Anal Disorder
- What is being tested?
- Dietary Fiber, Proctoscopy or anoscopy with Biopsy and Colonoscopy
- Type of treatment
- Pill or oral medicine, Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 120 participants
- Where
- 1 siteUnited States
- Study dates
- 1 Apr 2023to 31 Dec 2026
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Age >= 18 years
- Ability to understand and the willingness to sign a written informed consent document
- Patients who present with a chief complaint of a benign anorectal pathology including hemorrhoids, anal fissures, and anal fistulas without underlying conditions such as colorectal cancer or Crohn's disease or are undergoing a standard of care colonoscopy procedure
Who cannot join
- Patients with an active malignancy, Crohn's disease, ulcerative colitis, and immunosuppressed patients
- Patients with hereditary colon cancer syndrome including Lynch syndrome or Familial Adenomatous Polyposis (FAP)
- Patients with a prior history of total or partial colon resection
- Colorectal pathology, such cancer or proctitis, after initial study scope
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Amber O'Connor contact
United States1 site, 1 recruiting
- Recruiting
OHSU Knight Cancer Institute
Portland, Oregon, 97239
Vassiliki L. Tsikitis, M.D., 503-494-1735, tsikitis@ohsu.edu
Vassiliki L. Tsikitis, M.D.
About this study
Official title: Changes in Colonic Microbiome With Fiber Supplementation
This clinical trial tests whether daily fiber supplementation will change the mucosal microbiome of the colon. The microbiome are microorganisms that live in the human gut. They serve a vital role in maintaining health. Certain microbial strains are associated with the growth of colon polyps, which eventually could go on to form colon cancer. Giving dietary fiber supplements may help prevent precancerous polyps from ever developing.
Read the detailed description
PRIMARY OBJECTIVE:
- To identify how diet, specifically fiber supplementation, alters the microbiome of the colonic mucosa.
OUTLINE:
Patients receive dietary fiber orally (PO) once daily (QD) for 28 days. Patients may undergo standard of care proctoscopy or anoscopy with biopsy on study and at follow up or may undergo standard of care colonoscopy on study. All patients also undergo collection of blood samples on study and at follow up.
- Being tested
- Dietary Fiber, Proctoscopy or anoscopy with Biopsy, Colonoscopy, Questionnaire Administration
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Dietary FiberDietary supplement
Also called Fiber
Given PO
Proctoscopy or anoscopy with BiopsyProcedure or surgery
Undergo proctoscopy or anoscopy
ColonoscopyProcedure or surgery
Undergo Colonoscopy
Questionnaire AdministrationOther
Ancillary studies
| Study group | Role | What they receive |
|---|---|---|
| Supportive care (oral fiber) | Experimental | Patients receive dietary fiber orally (PO) on study. QD for 28 days. Patients may undergo standard of care proctoscopy or anoscopy with biopsy on study and duringat follow- up or may undergo standard of care colonoscopy on study. All patients also undergo collection of blood samples on study and at follow up. Receives: Dietary Supplement: Dietary Fiber; Procedure: Proctoscopy or anoscopy with Biopsy; Procedure: Colonoscopy; Other: Questionnaire Administration |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in microbiome colonic mucosa: taxa abundance
Will use data visualization techniques to understand the data and determine if microbiome count overall (richness) changes occur in patients who are started on fiber supplementation. In order to visualize overall changes after fiber supplementation, will generate plots showing relative abundance of the detected taxa for each subject at baseline and post-supplementation. For each taxa, will generate box plots to visually compare the median and interquartile range (IQR) of abundance between the two time points. Wilcoxon signed rank tests with an alpha level of 0.05 will determine if there is a difference in microbial derived short chain fatty acids after fiber supplementation in the blood and mucosa. Wilcoxon signed rank tests with an alpha level of 0.05 will determine if there is a difference in microbial derived short chain fatty acids after fiber supplementation in the blood and mucosa.
Measured: Baseline and post-supplementation, up to 40 days
Change in microbiome colonic mucosa: microbiome diversity
Will use data visualization techniques to understand the data and determine if the types of metabolites (microbiome diversity) cases occur in patients who are started on fiber supplementation. In order to visualize overall changes after fiber supplementation. To assess for changes in microbiome diversity, our primary analysis will compare median Shannon diversity index values at baseline and post-supplementation. The Shannon index estimates diversity using richness and abundance. Will calculate Shannon index values for each participant at each time point and use a Wilcoxon signed rank test with an alpha level of 0.05 to determine if there is a difference in microbiome diversity after fiber supplementation.
Measured: Baseline and post-supplementation, up to 40 days
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted9 Dec 2022
- Study start1 Apr 2023
- Primary completion31 Dec 2026 (estimated)
- Study completion31 Dec 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Benign Colorectal NeoplasmStudies of the same condition, open and under way.
- More trials run by OHSU Knight Cancer InstituteThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Supportive care
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 120 participants (estimated)
Sponsor and investigators
- Lead sponsor
- OHSU Knight Cancer Institute
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Vassiliki Tsikitis, OHSU Knight Cancer Institute
- Investigators
- Vassiliki L Tsikitis, M.D., Principal investigator, OHSU Knight Cancer Institute
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05643859
- Sponsor's protocol ID
- STUDY00024054
- Other IDs
- NCI-2022-07495, STUDY00024054
- Status last verified
- Jan 2026
- First submitted
- 26 Sep 2022
- Last updated
- 15 Jan 2026
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: Study team plans to publish the results in the Journal for Microbiome
Study at a glance
From the registry record, last updated by the sponsor on 15 Jan 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Changes in Colonic Microbiome With Fiber Supplementation
- ClinicalTrials.gov ID
- NCT05643859
- Acronym / sponsor ID
- STUDY00024054
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 120 participants (estimated)
- Lead sponsor
- OHSU Knight Cancer InstituteUniversity, hospital or other
- Study start
- 1 Apr 2023 (actual)
- Primary completion
- 31 Dec 2026 (estimated)
- Study completion
- 31 Dec 2026 (estimated)
- First posted
- 9 Dec 2022 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This clinical trial tests whether daily fiber supplementation will change the mucosal microbiome of the colon. The microbiome are microorganisms that live in the human gut. They serve a vital role in maintaining health. Certain microbial strains are associated with the growth of colon polyps, which eventually could go on to form colon cancer. Giving dietary fiber supplements may help prevent precancerous polyps from ever developing.
Detailed description
PRIMARY OBJECTIVE:
- To identify how diet, specifically fiber supplementation, alters the microbiome of the colonic mucosa.
OUTLINE:
Patients receive dietary fiber orally (PO) once daily (QD) for 28 days. Patients may undergo standard of care proctoscopy or anoscopy with biopsy on study and at follow up or may undergo standard of care colonoscopy on study. All patients also undergo collection of blood samples on study and at follow up.
Study design
- Primary purpose
- Supportive care
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Supportive care (oral fiber) | Experimental | Dietary Supplement: Dietary Fiber, Procedure: Proctoscopy or anoscopy with Biopsy, Procedure: Colonoscopy, Other: Questionnaire AdministrationPatients receive dietary fiber orally (PO) on study. QD for 28 days. Patients may undergo standard of care proctoscopy or anoscopy with biopsy on study and duringat follow- up or may undergo standard of care colonoscopy on study. All patients also undergo collection of blood samples on study and at follow up. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- Age >= 18 years
- Ability to understand and the willingness to sign a written informed consent document
- Patients who present with a chief complaint of a benign anorectal pathology including hemorrhoids, anal fissures, and anal fistulas without underlying conditions such as colorectal cancer or Crohn's disease or are undergoing a standard of care colonoscopy procedure
Key exclusion criteria (4 listed)
- Patients with an active malignancy, Crohn's disease, ulcerative colitis, and immunosuppressed patients
- Patients with hereditary colon cancer syndrome including Lynch syndrome or Familial Adenomatous Polyposis (FAP)
- Patients with a prior history of total or partial colon resection
- Colorectal pathology, such cancer or proctitis, after initial study scope
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Dietary FiberAlso: FiberGiven PO | Dietary supplement | Supportive care (oral fiber) |
| Proctoscopy or anoscopy with BiopsyUndergo proctoscopy or anoscopy | Procedure or surgery | Supportive care (oral fiber) |
| ColonoscopyUndergo Colonoscopy | Procedure or surgery | Supportive care (oral fiber) |
| Questionnaire AdministrationAncillary studies | Other | Supportive care (oral fiber) |
Primary outcome
Change in microbiome colonic mucosa: taxa abundance
Time frame: Baseline and post-supplementation, up to 40 days
Will use data visualization techniques to understand the data and determine if microbiome count overall (richness) changes occur in patients who are started on fiber supplementation. In order to visualize overall changes after fiber supplementation, will generate plots showing relative abundance of the detected taxa for each subject at baseline and post-supplementation. For each taxa, will generate box plots to visually compare the median and interquartile range (IQR) of abundance between the two time points. Wilcoxon signed rank tests with an alpha level of 0.05 will determine if there is a difference in microbial derived short chain fatty acids after fiber supplementation in the blood and mucosa. Wilcoxon signed rank tests with an alpha level of 0.05 will determine if there is a difference in microbial derived short chain fatty acids after fiber supplementation in the blood and mucosa.
Change in microbiome colonic mucosa: microbiome diversity
Time frame: Baseline and post-supplementation, up to 40 days
Will use data visualization techniques to understand the data and determine if the types of metabolites (microbiome diversity) cases occur in patients who are started on fiber supplementation. In order to visualize overall changes after fiber supplementation. To assess for changes in microbiome diversity, our primary analysis will compare median Shannon diversity index values at baseline and post-supplementation. The Shannon index estimates diversity using richness and abundance. Will calculate Shannon index values for each participant at each time point and use a Wilcoxon signed rank test with an alpha level of 0.05 to determine if there is a difference in microbiome diversity after fiber supplementation.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 15 Jan 2026.
- Individual participant dataSharing planned: Yes. Study team plans to publish the results in the Journal for Microbiome
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Amber O'Connor contact
Vassiliki L Tsikitis, M.D. principal investigator
OHSU Knight Cancer Institute
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Dietary Fiber, Proctoscopy or anoscopy with Biopsy and Colonoscopy in people with Benign Colorectal Neoplasm and Non-Neoplastic Anal Disorder, run by OHSU Knight Cancer Institute at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 15 Jan 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Shahrose Rahman, M.D. (503-494-8652, rahmasha@ohsu.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in microbiome colonic mucosa: taxa abundance (time frame: Baseline and post-supplementation, up to 40 days). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 15 Jan 2026.