ClinicalTrials.gg
RecruitingNCT06738173GUILTIUpdated Aug 13, 2026

Microbiome-based Diagnostic Tool for the Screening of Colorectal Cancer (GUILTI)

An observational study in Colorectal Cancer, sponsored by Catholic University of the Sacred Heart. Recruiting at 1 site in Italy. Open to participants aged 50 Years to 74 Years. Per ClinicalTrials.gov, last updated 2026-08-13.

Sponsored by Catholic University of the Sacred Heart · Observational

From the registry’s dates

  • Started Feb 2025; still recruiting 1 year 9 months later.
Study type
Observational
Model
Cohort
Time perspective
Cross-sectional
Enrollment
1,202
Ages
50 Years to 74 Years
Sex
All
01

Study summary

Colorectal cancer (CRC) is one of the most common cancer and cause of cancer death worldwide. Population-based screening programs for average risk populations have proven effective in reducing both incidence and mortality of CRC through early detection of cancer. The fecal immunochemical testing (FIT), has still a suboptimal diagnostic yield, with both missed adenomas and, mainly, unnecessary colonoscopies.The identification of novel, non-invasive biomarkers is currently one of the research areas driving most expenditure forces in the field of CRC.A large body of evidence shows that alterations of the gut microbiome and the enrichment of specific taxa(e.g. Fusobacterium nucleatum, Parvimonas micra, and others) are involved in the pathogenesis of CRC. Moreover, recent studies, have discovered common microbial signatures able to reproducibly discriminate between patients with CRC and healthy controls.The goal of this observational study to develop a gut microbiome based diagnostic tool for the identification of CRC and advanced colorectal adenomas in patients enrolled in the national colorectal cancer (CRC) screening program (50-74 year-old) and among who refer to all centers involved in this study for screening colonoscopy with positivity of FIT, of both sex. The primary endpoint of the study is to develop a gut microbiome-based diagnostic tool for the identification of CRC and advanced colorectal adenomas in patients involved in the national CRC screening program, using both statistical and machine learning approaches. The secondary endpoints are:

  • The association of clinical and colonoscopy outcomes with FIT results;
  • The characterization of gut microbiome from an ecological, taxonomic, phylogenetic and functional point of view;
  • The association between microbiome signatures with clinical and colonoscopy outcomes, through statistical and machine-learning algorithms. At baseline, enrolled patients will provide a fecal sample within 2 weeks from enrollment and demographic, clinical characteristics and laboratory data will be recorded. Enrolled patients will be scheduled for colonoscopy, as for clinical practice, within 4 weeks from the positive FIT and histology of resected lesions will be assessed by experienced pathologists according to the WHO classification and the Vienna criteria. Clinical, endoscopic and microbial data will be combined through statistical and machine learning algorithms to identify specific microbial biomarkers associated with CRC and develop a new diagnostic tool, based on a scoring system. This tool will be validated, and its diagnostic performances will be compared with traditional screening methods.
Read the detailed description

Colorectal cancer (CRC) is the 3rd most common cancer and the 2nd most common cause of cancer death worldwide, with nearly 2 million new cases and one million deaths in 2020. In the last decades, a population-based screening programs for average-risk populations have established as an effective strategy to reduce both incidence and mortality of CRC through early detection of cancer. The fecal immunochemical testing (FIT), the reference diagnostic tool in most countries, has still a suboptimal diagnostic yield, with both missed adenomas and, mainly, unnecessary colonoscopies. For these reasons, in the last years the identification of novel, non-invasive biomarkers is absolutely advocatein the field of CRC. A large body of evidence shows that alterations of the gut microbiome and the enrichment of specific taxa (e.g. Fusobacterium nucleatum, Parvimonas micra, and others) are involved in the pathogenesis of CRC. Moreover, recent studies, including metagenomic meta-analyses from our group, have discovered common microbial signatures able to reproducibly discriminate between patients with CRC and healthy controls. Based on this evidence, international guidelines have recently advocated the exploitation of microbiome-based biomarkers for the screening of CRC in clinical practice, but such studies are not yet available to date.

The primary objective is to develop a gut microbiome-based diagnostic tool for the identification of CRC and advanced colorectal adenomas.

The secondary objectives are:

  • To associate FIT with clinical and colonoscopy outcomes
  • To characterize gut microbiome of enrolled patients
  • To associate microbiome signatures with clinical and colonoscopy outcomes. This is an observational prospective multicenter study, in which patients will be selected among those enrolled in the national colorectal cancer (CRC) screening program and among who refer to all centers involved in this study for screening colonoscopy. Patients with all inclusion criteria and none of the exclusion criteria (detailed in the specific section of this website) will be considered for this study.N=1202 patients will be enrolled, based on sample size calculation and including a validation group. N=911 patients will be needed, and we will add 91 patients to cover a 10% potential drop-out and 200 patients as a validation group (20% of the study cohort). Patients enrolled in this validation cohort will have the same exclusion and inclusion criteria of other patients and will undergo the same study procedures. At baseline all enrolled patients will provide a fecal sample (collected using a buffer for genome preservation) within 2 weeks from enrollment and will be stored at -80°C at each clinical center and assigned de-identified IDs. Moreover demographic, clinical characteristics and laboratory data will be recorded.

For all enrolled patients clinicians will record the following data:

  • Familiar history of CRC;
  • Comorbidities;
  • Drug intake;
  • Gastrointestinal (GI) and alarm symptoms (iron-deficiency anemia, hematochezia, unexplained weight loss, abdominal pain, sudden change in bowel habits);
  • Dietary habits;
  • Smoking and alcohol consumption;
  • BMI (body mass index);
  • Information about previous FIT and/or colonoscopies and/or virtual colonoscopies.

All enrolled patients will undergo a colonoscopy within 4 weeks from the positive FIT, after colonoscopy endoscopic characteristics (size, site, shape based on Paris class.) and histopathological characteristics of detected lesions will be collected. Advanced colorectal adenomas will be defined as adenomas larger than or equal to 10 mm, and/or with villous components higher than or equal to 25%, and/or high-grade dysplasia.Moreover, patients diagnosed with CRC, will also undergo a total-body CT scan to stage the disease and will be referred to an oncological pathway in clinical practice, and the following data will be collected: presence of lymph node metastasis and of organ metastasis, TNM (Tumor-Node-Metastasis) class..The enrollment phase will last 48 months.At the end of the enrollment phase, the investigators will perform the microbiome analysis, and the investigators will combined clinical, endoscopic and microbial data through statistical and machine learning algorithms to identify specific microbial biomarkers associated with CRC and advanced colorectal adenomas, to develop a new diagnostic tool, based on a scoring system.

Study Outcomes are detailed in the specific section of this website. Microbiome analysis will be performed with shotgun sequencing techniques. Moreover to obtain a panel of microbial species mostly associated with CRC and advanced colorectal adenomas, the investigators will exploit machine learning applications, for instance, using the widely adopted Random Forest algorithms, as well as meta-analytical approaches integrating our large cohort with previously published metagenomic cohorts. A defined panel of microbial species mostly associated with CRC and advanced colorectal adenomas will provide a comprehensive risk score based on microbiome features, with two specific goals, to improve the accuracy testing of the FIT diagnostic tool and to be easily interpretable by clinicians.All the collected clinical data will be statistically combined to rank microbial features from the most to least associated.

These rankings will be exploited to evaluate a microbiome profile from a new individual, and to report how many of the defined species in the previous panel are found, and hence linked with CRC and advanced colorectal adenomas. Associations between identified species and makers of interest will be estimated through robust statistical analysis methods, such as partial correlation or linear modeling. Then the associations will be ranked and compared across markers for the same species, giving a priority score for each species. Particular care will be dedicated to identifying potential confounding markers known to be associated with differences in microbiome composition, for instance, age, that instead should be used as covariates in the statistical modeling. In addition to statistical modeling, associations between species and markers will also be evaluated via ML approaches, particularly those providing feature importance scores for the input features (species, in our case), that can be used to rank the species across the different markers (e.g. Random Forest, LASSO, etc). Continuous variables will be reported as mean ± standard deviation or as median and interquartile range (IQR), and categorical variables were summarized as frequency and percentage. Comparisons of variables will be made by t-test (or Mann-Whitney/Kruskal-Wallis), Chi-square test, or Fisher\'s exact test, as appropriate. A p-value \<0.05 will be considered to indicatestatistical significance. Logistic regression models will be performed to identify the presence of variables independently associated with outcomes. Variables considered in the models were selected through stepwise model selection and guided by clinical relevance. All statistical analyses were performed using SPSS v. 28.0 for Macintosh (SPSS Inc., Chicago, USA).

The investigators will employ a Machine Learning (ML) framework based on the scikit-learn Python package using a cross-validation approach with 100 bootstrap iterations and an 80/20 random splitting into training and testing folds. Classification and regression ML algorithms will be trained on both microbiome species-level taxonomic relative abundances and functional potential profiles. Species-level taxonomic abundances will be estimated by MetaPhlAn 4 (using the latest databases available, currently named Oct22) and normalized using the arcsin-sqrt transformation for compositional data. Functional potential profiles will be estimated using the latest HUMAnN 4 version and the investigators will consider both abundance estimations of single microbial gene families and of metabolic pathways. Partial correlations between species and markers will be computed using the Spearman index, to avoid biases due to outlier values and corrected for covariates, such as sex, age, and body-mass index, known to have an impact on microbiome composition. Partial correlation values will be corrected using the Benjamini-Hochberg procedure for the false-discovery rate.

02

Conditions studied

  • Colorectal Cancer

Keywords

  • microbiome testing
  • microbiome
  • colorectal cancer screening
  • colorectal cancer
03

In context

Colorectal Neoplasms

6,541 studies on the registry are indexed under Colorectal Neoplasms; 1,667 are open to participants now.

This study's planned enrollment of 1,202 is above the median of 250 across 1,440 observational studies indexed under Colorectal Neoplasms.

Browse Colorectal Neoplasms studies →

Lead sponsor

Catholic University of the Sacred Heart is the lead sponsor of 237 studies on the registry; 29 are open to participants now.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
50 Years to 74 Years
Sexes eligible
All
Accepts healthy volunteers
No
Sampling method
Non-probability sample

Study population

Participants will be selected among those enrolled in the national colorectal cancer (CRC) screening program and among who refer to all centers involved in this study for screening colonoscopy. Patients with all inclusion criteria and none of the exclusion criteria will be considered for this study. A total of 1202 patients will be enrolled, based on sample size calculation and including a validation group. N=911 patients will be needed, and we will add 91 patients to cover a 10% potential drop-out and 200 patients as a validation group (20% of the study cohort). Patients enrolled in this validation cohort will have the same exclusion and inclusion criteria of other patients and will undergo the same study procedures.

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

  • Patients participating in the national CRC screening program (50-74 years old)
  • Positivity to the FIT;
  • Ability to provide written and to be compliant with the study procedures.

Exclusion criteria

Exclusion Criteria:

  • Patients unfit for colonoscopy;
  • Other oncological conditions;
  • Concomitant severe comorbidities or gastrointestinal (GI) organic diseases (e.g. diverticular disease, inflammatory bowel disease);
  • Antibiotics, proton pump inhibitors or probiotics within 4 weeks prior to enrollment.
Terms in these criteria, in plain language(1)

Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.

Informed consent

Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.

You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.

05

Study design

Observational model
Cohort
Time perspective
Cross-sectional
Enrollment
1,202 participants (estimated)
Patient registry
No
Biospecimen retention
Samples with dna

Groups and cohorts

  • Groups/Cohorts

    Study cohort consists of patients enrolled in the national colorectal cancer (CRC) screening program.Participants will be selected among those enrolled in the nationalcolorectal cancer (CRC) screening program and among who refer to all centers involved in this study for screening colonoscopy. Patients with all inclusion criteria and none of the exclusion criteria will be considered for this study. N=1202 patients will be enrolled, based on sample size calculation and including a validation group. N=911 patients will be needed, and we will add 91 patients to cover a 10% potential drop-out and 200 patients as a validation group (20% of the study cohort).

    Diagnostic Test: Gut microbiome testing

Interventions

  • Diagnostic testGut microbiome testing

    Gut microbiome testing for the characterization of the patient gut microbiome

06

What researchers measure

Primary outcomes

  1. Gut microbiome-based diagnostic tool for CRC and advanced colorectal adenomas detection

    Discovery of a gut microbial signature able to predict the diagnosis of colorectal cancer and advanced colorectal adenomas

    Time frame: 60 months

Secondary outcomes

  1. Correlation between clinical and endoscopic outcomes with FIT

    The correlation of clinical and colonoscopy outcomes with fecal immunochemical testing results

    Time frame: 60 months

  2. Microbiome characteristics of fecal samples

    The characterization of gut microbiome from an ecological, taxonomic, phylogenetic and functional point of view

    Time frame: 60 months

  3. Correlation between microbiome signatures with clinical and endoscopic outcomes

    The correlation between microbiome signatures with clinical and colonoscopy outcomes, through statistical and machine-learning algorithms

    Time frame: 60 months

07

Study locations

1 of 1 sites recruiting
08

References and documents

Publications

  • Pasolli E, Asnicar F, Manara S, Zolfo M, Karcher N, Armanini F, Beghini F, Manghi P, Tett A, Ghensi P, Collado MC, Rice BL, DuLong C, Morgan XC, Golden CD, Quince C, Huttenhower C, Segata N. Extensive Unexplored Human Microbiome Diversity Revealed by Over 150,000 Genomes from Metagenomes Spanning Age, Geography, and Lifestyle. Cell. 2019 Jan 24;176(3):649-662.e20. doi: 10.1016/j.cell.2019.01.001. Epub 2019 Jan 17. PubMed 30661755 ↗
  • Blanco-Miguez A, Beghini F, Cumbo F, McIver LJ, Thompson KN, Zolfo M, Manghi P, Dubois L, Huang KD, Thomas AM, Nickols WA, Piccinno G, Piperni E, Puncochar M, Valles-Colomer M, Tett A, Giordano F, Davies R, Wolf J, Berry SE, Spector TD, Franzosa EA, Pasolli E, Asnicar F, Huttenhower C, Segata N. Extending and improving metagenomic taxonomic profiling with uncharacterized species using MetaPhlAn 4. Nat Biotechnol. 2023 Nov;41(11):1633-1644. doi: 10.1038/s41587-023-01688-w. Epub 2023 Feb 23. PubMed 36823356 ↗
  • Beghini F, McIver LJ, Blanco-Miguez A, Dubois L, Asnicar F, Maharjan S, Mailyan A, Manghi P, Scholz M, Thomas AM, Valles-Colomer M, Weingart G, Zhang Y, Zolfo M, Huttenhower C, Franzosa EA, Segata N. Integrating taxonomic, functional, and strain-level profiling of diverse microbial communities with bioBakery 3. Elife. 2021 May 4;10:e65088. doi: 10.7554/eLife.65088. PubMed 33944776 ↗
  • Schlemper RJ, Riddell RH, Kato Y, Borchard F, Cooper HS, Dawsey SM, Dixon MF, Fenoglio-Preiser CM, Flejou JF, Geboes K, Hattori T, Hirota T, Itabashi M, Iwafuchi M, Iwashita A, Kim YI, Kirchner T, Klimpfinger M, Koike M, Lauwers GY, Lewin KJ, Oberhuber G, Offner F, Price AB, Rubio CA, Shimizu M, Shimoda T, Sipponen P, Solcia E, Stolte M, Watanabe H, Yamabe H. The Vienna classification of gastrointestinal epithelial neoplasia. Gut. 2000 Aug;47(2):251-5. doi: 10.1136/gut.47.2.251. PubMed 10896917 ↗
  • Kaminski MF, Thomas-Gibson S, Bugajski M, Bretthauer M, Rees CJ, Dekker E, Hoff G, Jover R, Suchanek S, Ferlitsch M, Anderson J, Roesch T, Hultcranz R, Racz I, Kuipers EJ, Garborg K, East JE, Rupinski M, Seip B, Bennett C, Senore C, Minozzi S, Bisschops R, Domagk D, Valori R, Spada C, Hassan C, Dinis-Ribeiro M, Rutter MD. Performance measures for lower gastrointestinal endoscopy: a European Society of Gastrointestinal Endoscopy (ESGE) Quality Improvement Initiative. Endoscopy. 2017 Apr;49(4):378-397. doi: 10.1055/s-0043-103411. Epub 2017 Mar 7. PubMed 28268235 ↗
  • Thomas AM, Manghi P, Asnicar F, Pasolli E, Armanini F, Zolfo M, Beghini F, Manara S, Karcher N, Pozzi C, Gandini S, Serrano D, Tarallo S, Francavilla A, Gallo G, Trompetto M, Ferrero G, Mizutani S, Shiroma H, Shiba S, Shibata T, Yachida S, Yamada T, Wirbel J, Schrotz-King P, Ulrich CM, Brenner H, Arumugam M, Bork P, Zeller G, Cordero F, Dias-Neto E, Setubal JC, Tett A, Pardini B, Rescigno M, Waldron L, Naccarati A, Segata N. Metagenomic analysis of colorectal cancer datasets identifies cross-cohort microbial diagnostic signatures and a link with choline degradation. Nat Med. 2019 Apr;25(4):667-678. doi: 10.1038/s41591-019-0405-7. Epub 2019 Apr 1. PubMed 30936548 ↗
  • Thomas AM, Manghi P, Asnicar F, Pasolli E, Armanini F, Zolfo M, Beghini F, Manara S, Karcher N, Pozzi C, Gandini S, Serrano D, Tarallo S, Francavilla A, Gallo G, Trompetto M, Ferrero G, Mizutani S, Shiroma H, Shiba S, Shibata T, Yachida S, Yamada T, Wirbel J, Schrotz-King P, Ulrich CM, Brenner H, Arumugam M, Bork P, Zeller G, Cordero F, Dias-Neto E, Setubal JC, Tett A, Pardini B, Rescigno M, Waldron L, Naccarati A, Segata N. Author Correction: Metagenomic analysis of colorectal cancer datasets identifies cross-cohort microbial diagnostic signatures and a link with choline degradation. Nat Med. 2019 Dec;25(12):1948. doi: 10.1038/s41591-019-0663-4. PubMed 31664237 ↗
  • Zeller G, Tap J, Voigt AY, Sunagawa S, Kultima JR, Costea PI, Amiot A, Bohm J, Brunetti F, Habermann N, Hercog R, Koch M, Luciani A, Mende DR, Schneider MA, Schrotz-King P, Tournigand C, Tran Van Nhieu J, Yamada T, Zimmermann J, Benes V, Kloor M, Ulrich CM, von Knebel Doeberitz M, Sobhani I, Bork P. Potential of fecal microbiota for early-stage detection of colorectal cancer. Mol Syst Biol. 2014 Nov 28;10(11):766. doi: 10.15252/msb.20145645. PubMed 25432777 ↗
  • Wong CC, Yu J. Gut microbiota in colorectal cancer development and therapy. Nat Rev Clin Oncol. 2023 Jul;20(7):429-452. doi: 10.1038/s41571-023-00766-x. Epub 2023 May 11. PubMed 37169888 ↗
  • Chan FKL, Wong MCS, Chan AT, East JE, Chiu HM, Makharia GK, Weller D, Ooi CJ, Limsrivilai J, Saito Y, Hang DV, Emery JD, Makmun D, Wu K, Ali RAR, Ng SC. Joint Asian Pacific Association of Gastroenterology (APAGE)-Asian Pacific Society of Digestive Endoscopy (APSDE) clinical practice guidelines on the use of non-invasive biomarkers for diagnosis of colorectal neoplasia. Gut. 2023 Jul;72(7):1240-1254. doi: 10.1136/gutjnl-2023-329429. Epub 2023 Apr 5. PubMed 37019620 ↗
  • Ladabaum U, Dominitz JA, Kahi C, Schoen RE. Strategies for Colorectal Cancer Screening. Gastroenterology. 2020 Jan;158(2):418-432. doi: 10.1053/j.gastro.2019.06.043. Epub 2019 Aug 5. PubMed 31394083 ↗
  • Morikawa T, Kato J, Yamaji Y, Wada R, Mitsushima T, Shiratori Y. A comparison of the immunochemical fecal occult blood test and total colonoscopy in the asymptomatic population. Gastroenterology. 2005 Aug;129(2):422-8. doi: 10.1016/j.gastro.2005.05.056. PubMed 16083699 ↗
  • Quintero E, Castells A, Bujanda L, Cubiella J, Salas D, Lanas A, Andreu M, Carballo F, Morillas JD, Hernandez C, Jover R, Montalvo I, Arenas J, Laredo E, Hernandez V, Iglesias F, Cid E, Zubizarreta R, Sala T, Ponce M, Andres M, Teruel G, Peris A, Roncales MP, Polo-Tomas M, Bessa X, Ferrer-Armengou O, Grau J, Serradesanferm A, Ono A, Cruzado J, Perez-Riquelme F, Alonso-Abreu I, de la Vega-Prieto M, Reyes-Melian JM, Cacho G, Diaz-Tasende J, Herreros-de-Tejada A, Poves C, Santander C, Gonzalez-Navarro A; COLONPREV Study Investigators. Colonoscopy versus fecal immunochemical testing in colorectal-cancer screening. N Engl J Med. 2012 Feb 23;366(8):697-706. doi: 10.1056/NEJMoa1108895. PubMed 22356323 ↗
  • Gupta S, Halm EA, Rockey DC, Hammons M, Koch M, Carter E, Valdez L, Tong L, Ahn C, Kashner M, Argenbright K, Tiro J, Geng Z, Pruitt S, Skinner CS. Comparative effectiveness of fecal immunochemical test outreach, colonoscopy outreach, and usual care for boosting colorectal cancer screening among the underserved: a randomized clinical trial. JAMA Intern Med. 2013 Oct 14;173(18):1725-32. doi: 10.1001/jamainternmed.2013.9294. PubMed 23921906 ↗
  • Sung H, Ferlay J, Siegel RL, Laversanne M, Soerjomataram I, Jemal A, Bray F. Global Cancer Statistics 2020: GLOBOCAN Estimates of Incidence and Mortality Worldwide for 36 Cancers in 185 Countries. CA Cancer J Clin. 2021 May;71(3):209-249. doi: 10.3322/caac.21660. Epub 2021 Feb 4. PubMed 33538338 ↗

Individual participant data

Plan to share: Yes — The individual data of patients will be shared

Supporting information: Study protocol, Statistical analysis plan

Time frame: Data will be available after the completion of the study, for 5 years

Access criteria: Data will be given upon reasonable request to the PI

Data sharing details ↗ · roma.unicatt.it

09

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Aug 13, 2026, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
10

Registry details

Key details

Study ID
NCT06738173
Responsible party
Gianluca Ianiro (Principal Investigator, MD, PhD, Catholic University of the Sacred Heart) — Principal investigator
First posted
Dec 17, 2024
Start date
Feb 7, 2025
Primary completion
Sep 30, 2029 (estimated)
Completion
Sep 30, 2029 (estimated)
Last update
Aug 13, 2026

Study contacts

Gianluca Ianiro, MD, PhD
Contact
gianluca.ianiro@unicatt.it
0630159539
Serena Porcari, MD, PhD
Contact
serena.porcari@guest.policlinicogemelli.it
0630159539

Oversight

Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

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