Health A-Z

Medical Content Created by the Faculty of the
Harvard Medical School

Liver Cancer

What Is It?

Liver cancer is the uncontrolled growth of abnormal cells in the liver. The liver:

• Produces elements that help blood to clot

• Removes or neutralizes poisons, drugs and alcohol

• Manufactures bile, which helps the body to absorb fats and cholesterol

• Helps to maintain normal blood sugar levels

• Regulates several hormones

Cancer in the liver either starts in the liver (primary liver cancer) or spreads to the liver from other places in the body (secondary liver cancer). Primary liver cancer is the most common solid tumor worldwide, with more than one million cases diagnosed each year. However, it is relatively rare in the United States and Europe. The American Cancer Society estimates that more than 17,000 people are diagnosed with primary liver cancer each year. Most of them are over age 40, and more than 15,000 will die of the disease. In the United States, liver cancer is about twice as common in men as in women.

Most liver tumors in the United States have spread (metastasized) to the liver from other organs, most commonly from the colon, rectum, lung, breast, pancreas and stomach. When a cancer spreads to the liver from somewhere else, the cancer cells are the same in both places. For example, if lung cancer spreads to the liver, the cancerous cells in the liver are the same as the cancerous cells in the lung. For that reason, the person is treated for lung cancer, not liver cancer. Doctors would call the cancer in the liver "metastatic lung cancer." The liver is the most common place for cancer to spread.

Only primary liver cancer is treated as liver cancer. There are four main types of primary liver cancer:

• Hepatocellular carcinoma (hepatoma or HCC). This cancer accounts for about 84% of primary liver cancers in the United States. It behaves aggressively.

• Cholangiocarcinoma (bile duct cancer). This cancer accounts for about 13% of primary liver cancer in the United States. Several conditions increase the risk of developing this cancer, including gallstones, gallbladder inflammation and, sometimes, chronic ulcerative colitis (an inflammation of the large bowel).

• Angiosarcoma (hemangiosarcoma). This is a very rare form of liver cancer.

• Hepatoblastoma. This is a rare type of liver cancer usually found in children younger than age 4.

Risk Factors Factors that increase your risk of developing primary liver cancer include:

• Hepatitis, which is an inflammation of the liver caused by a viral infection. A different virus causes each of the six types (A, B, C, D, E and G). Hepatitis B and Hepatitis C are responsible for most cases of hepatocellular carcinoma. Hepatitis A does not increase your risk of developing liver cancer.

• Cirrhosis, which is the scarring of liver cells that has several causes. In the United States, the most common causes of cirrhosis are hepatitis C and drinking too much alcohol. Fifty percent to 70% of liver cancers in the United States are associated with cirrhosis.

• Direct contact with vinyl chloride (polyvinyl chloride or PVC). This chemical, used in manufacturing some types of plastics, such as PVC pipe, has been linked to hepatocellular carcinoma in some studies.

• Exposure to arsenic, a chemical used as a wood preservative, herbicide, insecticide, and in manufacturing some glass and metallic alloys. Some drinking water is contaminated by arsenic. It also exists in natural mineral deposits.

• Anabolic steroids, which are male hormones used to treat certain conditions, and are sometimes used illegally by athletes to enhance performance. Long-term use may slightly increase the risk of liver cancer.

• Tobacco use, which makes you more likely to develop other cancers that can spread to the liver, including cancers of the lung, colon and pancreas. It is not known whether there is a direct link between tobacco use and liver cancer.