Circulating tumor DNA (ctDNA) can detect tumors 2 to 3 years in advance. Circulating tumor DNA, that is, after the DNA of tumor cells is shed or apoptosis occurs, it enters into the human circulatory system, and through the screening of genomic fragments in the blood, it is able to detect tumors, and compared with traditional CT, MRI and other examinations, it can advance the time of detecting tumors by 2 to 3 years, and some patients can even reach 4 years. The accuracy of circulating tumor DNA can reach more than 90%, which can detect early tumors in time. Moreover, it is a minimally invasive technology suitable for high-risk groups, which can effectively improve the detection rate, cure rate and survival rate of cancer patients.