Recruiting

Dietary Fiber

Sponsor:

OHSU Knight Cancer Institute

Code:

NCT05643859

Conditions

Benign Colorectal Neoplasm

Non-Neoplastic Anal Disorder

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Not accepted

Interventions

Dietary Fiber

Proctoscopy or anoscopy with Biopsy

Colonoscopy

Questionnaire Administration

Study Details

Brief 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. 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.

Conditions

Benign Colorectal Neoplasm

Non-Neoplastic Anal Disorder

Study ID

NCT05643859

Start date

Apr 1, 2023

Status verified date

Jan, 2026

Completion date

Dec 31, 2026

Anticipated

Primary completion date

Dec 31, 2026

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Not accepted

Inclusion Criteria:

  • 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

Exclusion Criteria:

  • 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

Study Design

Enrollment

120 participants

Anticipated

Intervention Model

Single group

Primary purpose

Supportive Care

Interventions and Outcome Measures

Arms

experimental: Supportive care (oral fiber)

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.

Interventions

Dietary Fiber

Given PO

Proctoscopy or anoscopy with Biopsy

Undergo proctoscopy or anoscopy

Colonoscopy

Undergo Colonoscopy

Questionnaire Administration

Ancillary studies

Primary outcome measure

  • Change in microbiome colonic mucosa: taxa abundance [ Time Frame: Baseline and post-supplementation, up to 40 days ]
  • Change in microbiome colonic mucosa: microbiome diversity [ Time Frame: Baseline and post-supplementation, up to 40 days ]

Central Contacts and Locations

Central contacts

Shahrose Rahman, M.D.

503-494-8652rahmasha@ohsu.edu

Amber O'Connor

oconnoam@ohsu.edu

Locations

OHSU Knight Cancer Institute

Recruiting

Portland, Oregon, United States, 97239

Contacts

Vassiliki L. Tsikitis, M.D.

503-494-1735tsikitis@ohsu.edu

Principal Investigator:

Vassiliki L. Tsikitis, M.D.

More Information

Sponsor

OHSU Knight Cancer Institute

Last update posted

Jan 15, 2026

Last verified

Jan, 2026

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-10. This information was provided to ClinicalTrials.gov by OHSU Knight Cancer Institute on 2026-01-15.