ctDNA and TEP Levels in Colon Cancer

NCT07701408 | Not Yet Recruiting

• 1 other identifier: ORI2026-25
• Study Type: interventional
• Target: 80
• Locations: 1 country
• Sites: 1

Brief Summary

This interventional cohort study will evaluate circulating tumor DNA (ctDNA) and tumor-educated platelets (TEP) as blood-based biomarkers in adults with stage III colon cancer who are planned to receive neoadjuvant systemic therapy followed by surgical resection. Treatment will be given according to routine clinical practice and will depend on the biological characteristics of the tumor, including mismatch repair status. Participants will provide additional blood samples at predefined time points before, during, and after treatment and surgery. These samples will be used to analyze ctDNA and TEP and to assess whether changes in these biomarkers are associated with radiological response, pathological response, and disease-free outcomes. Approximately 80 participants will be enrolled at the Institute of Oncology Ljubljana. Participants will not receive experimental drugs as part of this study.

Conditions

Colon Cancer

Keywords

ctDNA; Circulating Tumor DNA; Tumor-Educated Platelets; TEP; Neoadjuvant Systemic Therapy

Outcome Measures

Primary Outcomes (1)

• Percentage of Participants With Major Pathological Response in the Post-Neoadjuvant ctDNA Assessment

  Major pathological response will be assessed by histopathological evaluation of the surgical resection specimen after completion of neoadjuvant systemic therapy. The unit of measure will be the percentage of participants with major pathological response. ctDNA status after completion of neoadjuvant systemic therapy will be used as a pre-specified stratification variable in the statistical analysis.

  From completion of neoadjuvant systemic therapy to pathological assessment after surgical resection, approximately 3 to 6 months.

Secondary Outcomes (6)

• Percentage of Participants With Objective Radiological Response According to RECIST 1.1

  From baseline to preoperative radiological assessment, approximately 3 to 6 months.

• Percentage of Participants Alive and Disease-Free at 12 Months After Surgical Resection

  12 months after surgical resection.

• Percentage of Participants With Early Disease Recurrence Within 12 Months After Surgical Resection in the Postoperative ctDNA Assessment

  Up to 12 months after surgical resection.

• Percentage of Participants With Early Disease Recurrence Within 12 Months After Surgical Resection in the Postoperative TEP Assessment

  Up to 12 months after surgical resection.

• Percentage of Participants With Major Pathological Response in the Baseline ctDNA Assessment

  From baseline to pathological assessment after surgical resection, approximately 3 to 6 months.

Study Arms (1)

Biomarker Assessment Cohort

OTHER

Participants with stage III colon cancer receiving neoadjuvant systemic therapy according to routine clinical practice will undergo additional peripheral venous blood sampling at predefined time points for ctDNA and TEP biomarker analysis.

Procedure: Additional Peripheral Venous Blood Sampling for ctDNA and TEP Biomarker Analysis

Interventions

Additional Peripheral Venous Blood Sampling for ctDNA and TEP Biomarker Analysis PROCEDURE

Additional peripheral venous blood samples will be collected at predefined time points before treatment, during systemic treatment, before surgery, and after surgery. Samples will be analyzed for circulating tumor DNA (ctDNA) and tumor-educated platelets (TEP).

Biomarker Assessment Cohort

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Age 18 years or older at the time of enrollment.
• Histologically confirmed adenocarcinoma of the colon.
• Stage III colon cancer, defined according to the applicable TNM classification based on clinical and imaging assessment.
• Confirmed mismatch repair (MMR) status, determined by immunohistochemistry and/or molecular methods.
• Planned neoadjuvant systemic therapy according to MMR status, followed by surgical resection with curative intent.
• ECOG performance status 0-2.
• Ability to understand the study and provide written informed consent.

You may not qualify if:

• Stage I, II, or IV colon cancer.
• Concurrent active malignant disease, except adequately treated non-melanoma skin cancer or carcinoma in situ.
• Severe comorbidities or medical conditions that prevent or substantially limit neoadjuvant systemic therapy or surgical resection.
• Known autoimmune disease requiring active immunosuppressive treatment in patients with dMMR tumors.
• Pregnancy or breastfeeding.
• Inability or unwillingness to provide written informed consent.

Sponsors & Collaborators

• Institute of Oncology Ljubljana: lead

Study Sites (1)

Institute of Oncology Ljubljana

Ljubljana, 1000, Slovenia

Location

MeSH Terms

Conditions

Colonic Neoplasms

Interventions

Circulating Tumor DNA

Condition Hierarchy (Ancestors)

Colorectal Neoplasms; Intestinal Neoplasms; Gastrointestinal Neoplasms; Digestive System Neoplasms; Neoplasms by Site; Neoplasms; Digestive System Diseases; Gastrointestinal Diseases; Colonic Diseases; Intestinal Diseases

Intervention Hierarchy (Ancestors)

Cell-Free Nucleic Acids; Nucleic Acids; Nucleic Acids, Nucleotides, and Nucleosides; DNA, Neoplasm; DNA

Central Study Contacts

Tanja Mesti, MD

CONTACT

+386 1 5879 287; tmesti@onko-i.si

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: DIAGNOSTIC
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: All participants will undergo additional peripheral venous blood sampling at predefined time points for ctDNA and TEP biomarker analysis while receiving neoadjuvant systemic therapy according to routine clinical practice.

Study Record Dates

• First Submitted: June 18, 2026
• First Posted: July 14, 2026
• Study Start: August 1, 2026
• Primary Completion (Estimated): June 1, 2028
• Study Completion (Estimated): June 1, 2028
• Last Updated: July 14, 2026

Record last verified: 2026-06

Data Sharing

• IPD Sharing: Will not share

Locations

SL (1)