A liver metastasis is a cancerous tumor that has spread to the liver from a cancer that started in another place in the body. It’s also called secondary liver cancer. Primary liver cancer originates in the liver and most commonly affects individuals who have risk factors such as hepatitis or cirrhosis. Liver metastases are tumors that have spread to the liver from other areas of the the body. Cancer cells often have aggressive tendencies and will invade other areas of the body. They usually do so by floating in the blood stream and then replicating themselves in a new place. The liver, in particular, provides a fertile soil for metastatic spread because of its rich blood supply and the presence of humoral factors (other bodily fluids) that promote cell growth. In terms of blood flow per minute, the blood supply of the liver is second only to the lung. cancers of the GI tract often spread to the liver because their blood drains directly through the liver. Melanoma usually spreads through the body's blood vessels to the liver. Liver metastases are sometimes present  when the original (primary) cancer is diagnosed, or it may occur months or years after the primary tumor is removed.