Many patients often ask me, “What exactly is portal vein cancer embolism?” Simply speaking, portal vein cancer thrombosis is a tumor cell that has grown into the portal vein and formed a thrombus, which is called portal vein cancer thrombosis. If patients with liver cancer have portal vein cancer thrombus, firstly, they will have symptoms related to liver cancer, such as nausea, abdominal pain (liver area), weakness, weight loss, jaundice, etc. Secondly, portal vein cancer thrombus will block blood vessels and affect the blood flow of portal vein, causing portal hypertension. Such patients will find enlarged spleen, hypersplenism, esophagogastric fundic varices, and some patients will vomit blood. Why is the portal vein prone to cancer clots? We know that 75% of the blood supply to the liver comes from the portal vein, and half of the liver’s oxygen is supplied through the portal vein. The portal vein is an important blood vessel connecting the liver with other organs in the abdominal cavity, and there are many branching vessels, through which cancer cells can easily enter the portal vein and form portal vein cancer thrombosis.