In advanced liver cancer, the tumor can spread locally to neighboring tissues or, through the blood vessels, elsewhere in the body (distant metastasis). Locally, liver cancer can invade the veins that drain the liver (hepatic veins). The tumor can then block these veins, which results in congestion of the liver. The congestion occurs because the blocked veins cannot drain the blood out of the liver. (Normally, the blood in the hepatic veins leaving the liver flows through the inferior vena cava, which is the largest vein that drains into the heart.) In African patients, the tumor frequently blocks the inferior vena cava. Blockage of either the hepatic veins or the inferior vena cava results in a very swollen liver and massive formation of ascites. In some patients, as previously mentioned, the tumor can invade the portal vein and lead to the rupture of esophageal varices.
Regarding distant metastases, liver cancer frequently spreads to the lungs, presumably by way of the bloodstream. Usually, patients do not have symptoms from the lung metastases, which are diagnosed by radiologic (X-ray) studies. Rarely, in very advanced cases, liver cancer can spread to the bone or brain. These are an infrequent problem in many patients who do not live long enough to develop these complications.
