An interventional study of Additional Peripheral Venous Blood Sampling for ctDNA and TEP Biomarker Analysis in Colon Cancer, sponsored by Institute of Oncology Ljubljana. Not yet recruiting at 1 site in Slovenia. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-10-07.
Sponsored by Institute of Oncology Ljubljana · Not applicable, Interventional, and Diagnostic
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.
This is a prospective interventional longitudinal cohort study of adult patients with histologically confirmed stage III colon adenocarcinoma who are planned to receive neoadjuvant systemic therapy followed by surgical resection with curative intent.
The study will evaluate the dynamics of circulating tumor DNA (ctDNA) and tumor-educated platelets (TEP) during neoadjuvant treatment and follow-up. Neoadjuvant systemic therapy will be selected according to routine clinical practice and tumor biology, including mismatch repair status. Patients with pMMR tumors may receive chemotherapy, while patients with dMMR tumors may receive immunotherapy, according to standard clinical decision-making.
The research intervention consists of additional peripheral venous blood sampling at predefined time points before treatment, during systemic treatment, before surgery, and after surgery. Blood samples will be analyzed for ctDNA and TEP-based biomarkers. Clinical, radiological, pathological, and follow-up data will be collected from routine medical documentation.
The primary objective is to determine whether the presence of ctDNA after completion of neoadjuvant systemic therapy is associated with pathological tumor response, defined as major pathological response (MPR), in patients with stage III colon cancer. Secondary and exploratory objectives include evaluation of the association between ctDNA, TEP profiles, radiological response, recurrence-free outcomes, and disease-free outcomes.
Approximately 80 participants will be enrolled. The study is academic and non-commercial. Participants will not receive experimental drugs as part of this study, and all therapeutic and diagnostic procedures will follow established clinical practice.
2,457 studies on the registry are indexed under Colonic Neoplasms; 458 are open to participants now.
This study's planned enrollment of 80 is close to the median of 75 across 1,711 interventional studies indexed under Colonic Neoplasms.
Browse Colonic Neoplasms studies →Institute of Oncology Ljubljana is the lead sponsor of 81 studies on the registry; 26 are open to participants now.
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Exclusion Criteria:
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.
The diagnosis was confirmed by looking at a sample under a microscope: tissue from a biopsy or surgery (histology), or cells from a fluid or needle sample (cytology).
Your pathology report is the document that shows this.
Neoadjuvant treatment is given before the main treatment (usually surgery), often to shrink a tumour. Adjuvant treatment is given after it, to lower the chance of the cancer coming back.
A scale of how much an illness limits everyday activity. For people being assessed to join a study, scores run from 0 (fully active) to 4; lower is more active.
Studies most often ask for 0–1 or 0–2. Your doctor gives the score; the WHO scale uses the same steps. The full scale also has 5, which records death.
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.
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Histologically or cytologically confirmed
The diagnosis was confirmed by looking at a sample under a microscope: tissue from a biopsy or surgery (histology), or cells from a fluid or needle sample (cytology).
Your pathology report is the document that shows this.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Adjuvant and neoadjuvant
Neoadjuvant treatment is given before the main treatment (usually surgery), often to shrink a tumour. Adjuvant treatment is given after it, to lower the chance of the cancer coming back.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ECOG performance status
A scale of how much an illness limits everyday activity. For people being assessed to join a study, scores run from 0 (fully active) to 4; lower is more active.
Studies most often ask for 0–1 or 0–2. Your doctor gives the score; the WHO scale uses the same steps. The full scale also has 5, which records death.
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.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Autoimmune disease
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Immunosuppression
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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
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).
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.
Time frame: From completion of neoadjuvant systemic therapy to pathological assessment after surgical resection, approximately 3 to 6 months.
Percentage of Participants With Objective Radiological Response According to RECIST 1.1
Radiological response will be assessed according to RECIST version 1.1 using routine preoperative imaging. Objective radiological response will include complete response and partial response. The unit of measure will be the percentage of participants with objective radiological response. ctDNA status after completion of neoadjuvant therapy will be used as a pre-specified stratification variable in the statistical analysis.
Time frame: From baseline to preoperative radiological assessment, approximately 3 to 6 months.
Percentage of Participants Alive and Disease-Free at 12 Months After Surgical Resection
Disease-free status will be assessed using routine clinical, radiological, and follow-up documentation. The outcome will be defined as being alive and without disease recurrence at 12 months after surgical resection. The unit of measure will be the percentage of participants alive and disease-free at 12 months. ctDNA status after completion of neoadjuvant therapy will be used as a pre-specified stratification variable in the statistical analysis.
Time frame: 12 months after surgical resection.
Percentage of Participants With Early Disease Recurrence Within 12 Months After Surgical Resection in the Postoperative ctDNA Assessment
Early disease recurrence will be assessed using routine clinical, radiological, and follow-up documentation. The unit of measure will be the percentage of participants with disease recurrence within 12 months after surgical resection. Postoperative ctDNA status will be used as a pre-specified stratification variable in the statistical analysis.
Time frame: 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
Early disease recurrence will be assessed using routine clinical, radiological, and follow-up documentation. The unit of measure will be the percentage of participants with disease recurrence within 12 months after surgical resection. Postoperative tumor-educated platelet status will be used as a pre-specified stratification variable in the statistical analysis.
Time frame: Up to 12 months after surgical resection.
Percentage of Participants With Major Pathological Response in the Baseline ctDNA Assessment
Major pathological response will be assessed by histopathological evaluation of the surgical resection specimen. The unit of measure will be the percentage of participants with major pathological response. Baseline ctDNA status will be used as a pre-specified stratification variable in the statistical analysis.
Time frame: From baseline to pathological assessment after surgical resection, approximately 3 to 6 months.
Percentage of Participants With Pathological Complete Response After Surgical Resection
Pathological complete response will be assessed by histopathological evaluation of the surgical resection specimen. The unit of measure will be the percentage of participants with pathological complete response. Baseline ctDNA status will be used as a pre-specified stratification variable in the statistical analysis.
Time frame: From baseline to pathological assessment after surgical resection, approximately 3 to 6 months.
Plan to share: No
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Institute of Oncology Ljubljana