Circulating Tumor DNA as a Biomarker in Colorectal Cancer: Diagnostic, Prognostic, and Therapeutic Perspectives

Circulating tumor DNA (ctDNA) is a type of cell-free DNA that originates from the shedding of tumor cells to the bloodstream and has recently been considered as a potential biomarker in colorectal cancer (CRC). This review covers the general features of ctDNA in terms of their biological properties and clinical applications, as well as the methods used to detect and quantify them. The clinical applications of ctDNA in CRC focus on early diagnosis, prognosis, therapeutic response monitoring, MRD evaluation and the resistance mechanisms. Although detection platforms digital PCR, NGS and methylation-based assays have been improved, several issues still need to be overcome such as low ctDNA frequency in early-stage disease and the absence of standardized protocols. The review also discusses prospects, including the embedding ctDNA with multi-omics approaches and artificial intelligence tools to enhance diagnostic precision. Overall, ctDNA is poised to revolutionize colorectal cancer care through its role in non-invasive, personalized, and dynamic disease management.