Early colorectal cancer screening increasingly detects small superficial colonic lesions, but current diagnostic tools still struggle to distinguish benign from malignant lesions and to assess lymph node risk. As histology after resection has limited accuracy, many patients undergo unnecessary surgery.

Liquid biopsy, analyzing circulating biomarkers such as tumor DNA, extracellular vesicles, and nucleosomes, offers a non-invasive way to better classify these lesions. Emerging evidence suggests it may outperform current criteria for predicting lymph node involvement in T1 colorectal cancer.

This study will establish a biobank of 1,000 patients to identify blood-based signatures that predict tumor stage and lymph node status. The hypothesis of the study is that circulating biomarkers can accurately differentiate benign from malignant lesions and identify patients with or without lymph node metastasis.

Introduction :

Early colorectal cancer screening increasingly identifies superficial colonic lesions, but current diagnostic tools often fail to accurately distinguish benign from malignant lesions or to predict lymph node involvement. As histological criteria have limited predictive value, many patients with T1 tumors undergo unnecessary surgery. Liquid biopsy, based on circulating blood biomarkers, offers a promising non-invasive alternative that may improve diagnostic precision.

Aim :

The study aims to build a biobank of 1,000 patients with superficial colonic tumors to identify and validate circulating biomarker signatures capable of predicting tumor malignancy and lymph node status. The hypothesis is that liquid biopsy markers can reliably differentiate benign from malignant lesions and identify patients at risk of lymph node metastasis.

Methods :

This is a multicenter prospective cohort study embedded in the FECCo cohort. Blood samples will be collected at the time of endoscopic resection and, for pT1 lesions, again 2-6 weeks later. Clinical data will be retrieved annually from the FECCo database. Diagnostic performance of circulating biomarkers will be assessed using ROC curves, logistic regression (Lasso), and bootstrap validation to identify signatures associated with malignancy and lymph node involvement.

Inclusion Criteria:

• Patient of legal age (≥ 18 years)
• Patient with a superficial colonic tumor refered for submucosal dissection
• Patient included in the FECCo cohort (patients will be included concomitantly in FECCO-Biobank)
• Patient wishing to participate in the FECCO-BioBank biological collection

Exclusion Criteria:

• Person with significant comorbidities preventing blood sampling
• Patients with a distant metastasis detected by imaging
• Person unable to read and write French
• Person who have expressed their opposition to participating in this research after being informed by an investigator and having read the information sheet
• Person not benefiting from a national health insurance scheme
• Person under legal protection, guardianship or curatorship
• Person participating in other study with an ongoing exclusion period

Eligible patients will be identified and recruited in gastroenterology consultations, within the investigating centers to which they will be referred as part of routine care.