Cancer embolus is formed when a large number of cancer cells converge into a mass in the blood, similar to what is called thrombus, which will transfer and spread with the flow of blood and stay in other organs, thus resulting in metastasis of cancer cells, but not all cancer embolus will lead to metastasis, and it needs to be determined by the situation of its formation. However, not all cancer clots will lead to metastasis, and it depends on their formation. If the cancer clots are only formed locally, they can be taken out during resection surgery to prevent them from spreading and metastasizing; however, if the clots are formed in the distal part of the body, it will be more difficult to treat them, and the prognosis is not very good, and most of the patients can only undergo radiotherapy, chemotherapy and targeted therapy.