CTC test is the abbreviation of circulating tumor cell test, which refers to the tumor cells shed from the primary tumor into the body fluid and participate in the body circulation. This test can monitor the tumor and make judgment on the prognosis.CTC test has both advantages and disadvantages.1. Advantages: CTC test only needs to collect venous blood, no radiation, and less trauma. It can also be repeatedly sampled in order to monitor tumor progression in real time. In addition, doctors can predict the patient’s response to treatment and prognosis by circulating tumor cells in the patient’s blood. 2. Disadvantages: Since CTC examination is an emerging technology, there is no clear conclusion on cancer metastasis, and high CTC does not necessarily mean cancer metastasis. Secondly, CTC examination is more expensive, and if multiple follow-ups are required, it may not be acceptable to the general income group. In addition, the sensitivity and accuracy of CTC screening technology are still not high. To sum up, patients can consider whether to have CTC examination according to their specific conditions and doctor’s recommendation.