Two ways in which cancer can involve the liver. The cancer can arise from the liver itself (primary liver cancer) or it can spread to the liver from a primary tumor at another site (secondary, or metastasis, cancer).
In the UK, secondary liver cancer is about 28 times more common than primary liver cancer. Each year there are about 70,000 patients in the UK with secondary liver cancer and about 2,500 with primary liver cancer.
Primary liver cancer can arise from the liver cells themselves (hepatocellular carcinoma) or from the system of tubes that drains the bile from the liver (cholangiocarcinoma, gall bladder cancer). Most patients with primary liver cancer have suffered previously from liver disease such as chronic hepatitis, cirrhosis or, in the less developed world, been exposed to poisons .
Secondary (metastasis) cancer reaches the liver by spreading through the blood system from a primary tumor at a separate site. In about 50 percent of patients with metastasis liver cancer, the primary tumor is in the bowel (colon, rectum) or stomach. The other common primary sites are the breasts and lungs.
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