Cancer embolism may appear in a few months after getting cancer, or it may appear in a year or so, or it may not appear for decades, which varies very much among different cancers. Cancer embolism is one of the common complications of tumors, which mainly refers to the appearance of cancer cells similar to blood clots in blood vessels or lymphatic vessels, and some tissues next to them gathering into a mass, invading blood vessels and lymphatic vessels, causing blood flow obstruction, and also to facilitate the migration and metastasis of such cancer cells themselves along blood channels or lymphatic vessels. It varies very much among different cancers, such as hepatocellular carcinoma, which is particularly prone to form cancerous embolisms, and once it has formed, it is likely to do so within a short period of time, within 1-2 months. For example, in thyroid cancer, well-differentiated papillary thyroid cancer may not form a cancerous embolus for the rest of its life, or for 10 years long, and it remains confined to the peritoneum. So the occurrence of cancer emboli varies very much from cancer to cancer. Even within the same cancer, it varies depending on the different degrees of differentiation of the tumor, and the invasive behavior. So there is no uniform time generalization, it can only be analyzed on an individual basis.