Role of Circulating Tumor DNA in Colorectal Cancer

Colorectal cancer (CRC) is a very common gastrointestinal tumor, ranking second in the global cause of cancer death. Because of the invasive nature of biopsy and cannot reflect the heterogeneity of tumor or monitor the dynamic progress of tumor, it is necessary to induce a novel noninvasive method to improve the current treatment strategies of colorectal cancer. Among all the components of liquid biopsy, circulating tumor DNA (ctDNA) may have the best future. CtDNA maintains the same genomic characteristics as those in matched tumor tissues, so it allows quantitative evaluation and analysis of mutation load in body fluid. Furthermore, because the half-life of ctDNA is from 16 min to several hours in circulation, the circulating ctDNA can be measured repeatedly within a certain period to monitor the response of CRC to treatment, the occurrence of drug resistance, and the diagnosis of recurrence.