Gut microbiome clues for colorectal cancer risk, progression, and outcomes

CARE-CRC: Microbiome Insights and Correlations for Risk and Outcomes in Colorectal Cancer

Observational Gulbenkian Institute for Molecular Medicine · NCT06734156

This study will try to find whether patterns in stool microbes can mark disease stage, prognosis, or treatment response in people aged 40–74 newly diagnosed with colorectal cancer.

Quick facts

Study typeObservational
Enrollment400 (estimated)
Ages40 Years to 74 Years
SexAll
SponsorGulbenkian Institute for Molecular Medicine Academic / other
Drugs / interventionschemotherapy
Locations2 sites (Lisbon, Lisbon District and 1 other locations)
Trial IDNCT06734156 on ClinicalTrials.gov

What this trial studies

Researchers will collect fecal samples from treatment‑naïve patients at diagnosis, after each therapeutic regimen (for example surgery or chemotherapy), and again three years after diagnosis to track changes in the gut microbiome over time. Microbiome profiles will be compared with healthy controls and analyzed alongside clinical, lifestyle, and dietary data, with results stratified by age and sex and with a focus on early‑onset cases. The study is observational and longitudinal, aiming to correlate microbial signatures with overall survival and disease‑free survival. Findings will be used to identify candidate biomarkers for validation in future work.

Who should consider this trial

Good fit: Adults aged 40 to 74 who are residents of Portugal, have a recent diagnosis of colorectal cancer, and have not yet started any cancer treatment are ideal candidates.

Not a fit: People younger than 40 or 75 and older, those with a first‑degree family history of CRC, prior inflammatory bowel disease, prior or current CRC treatment, pregnancy, or those unwilling to provide stool samples are not eligible and would not benefit from participation.

Why it matters

Potential benefit: If successful, this could identify stool microbiome markers that help detect disease stage, predict outcomes, and inform earlier or more personalized follow-up for colorectal cancer patients, particularly younger adults.

How similar studies have performed: Prior research has shown links between gut microbiota and colorectal cancer, but biomarker validation—especially for early‑onset CRC—is still limited and remains an active area of study.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Be willing and able to provide written informed consent
* Resident in Portugal
* Age from 40 to 74 years
* Have a recent diagnosis of CRC without initiating any treatment.

Exclusion Criteria:

* Age \< 40 years or ≥ 75 years
* Unable to provide informed consent
* Refusal to provide stool samples
* Previous or current treatment for CRC
* First-degree family history of CRC
* Previous diagnosis of inflammatory bowel disease (ulcerative colitis, Crohn's disease or indeterminate colitis), inflammatory bowel syndrome, recurrent infection by Clostridioides difficile
* Pregnancy

Where this trial is running

Lisbon, Lisbon District and 1 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Colorectal CancerMicrobiomeEarly Onset Colorectal CancerGut MicrobiotaEarly-onset Colorectal CancerBiomarkersDietRisk factors
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.