Importance of circulating tumor DNA in colorectal cancer

Space still exists in the management of patients with colorectal cancer (CRC) for improving risk stratification and thus the precision of treatment tailoring. Quite promising in this regard are biomarkers acquired via liquid biopsy, which is a non-invasive method of body fluid draw, most commonly peripheral blood. A variety of biomarkers associated with the tumor are analyzed, which can have either prognostic or predictive value. Circulating tumor DNA (ctDNA) is one of the most explored tumor biomarkers. Initially, its utility spectrum was only in advanced or metastatic cancers and consisted of molecular profiling and detecting acquired resistance to treatment. Nowadays, the use of circulating tumor DNA has shifted to earlier cancer stages, where it can identify minimal residual disease or diagnose colorectal cancer early. Existing studies show promising potential of these biomarkers, but more information needs to be gathered and information from ongoing studies needs to be obtained in order to use them in everyday practice.

In this review article, we will discuss ctDNA, its aspects, diag- nostic possibilities and current use in CRC.