MRD Monitoring in Colorectal Cancer Using ctDNA

This clinical study evaluates the use of free circulating tumor DNA (ctDNA) analysis from peripheral blood, known as liquid biopsy. The objective is to detect minimal residual disease (MRD) early and to predict disease relapse or progression in patients with colorectal cancer (stages II-IV). By monitoring specific KRAS gene mutations (G12 and G13) using the ddPCR method, the study aims to improve risk stratification and treatment response monitoring following primary therapy.

Inclusion Criteria: * Histologically confirmed diagnosis of colorectal cancer (clinical stage II, III, or IV). * Presence of KRAS gene mutation (specifically G12 or G13 mutations) confirmed in the primary tumor tissue. * Age 18 years or older at the time of inclusion. * Patient scheduled for standard primary surgical resection, local treatment, or adjuvant therapy as per institutional guidelines. * Signed written informed consent to participate in the study. Exclusion Criteria: * Absence of target KRAS mutations (G12/G13) in the primary tumor. * Inability or unwillingness to comply with scheduled blood sampling and follow-up visits. * Active second primary malignancy that could interfere with ctDNA interpretation.