Causes of Liver Cancer: Hepatitis, Cirrhosis and More

A number of factors increase a person's chance of developing primary liver cancer (also known as hepatoma). Age, gender and genes all play a part. Men are twice as likely to suffer from the disease as women and incidence rates increase after age 60. The role genetics plays is unclear, although researchers speculate that people with a family history of hepatomas are at greater than normal risk.

 

The exact cause of liver cancer remains a mystery. What is known, however, is that a number of health complications cause liver damage that can lead to the development of hepatomas.

Cirrhosis, or the buildup of scar tissue in the liver, increases the risk dramatically: 80 percent of hepatomas have been linked to cirrhosis. Inflammation of the liver kills healthy cells, which are replaced by scar tissue. The liver becomes deformed and cannot function effectively. Alcohol abuse is the leading cause of cirrhosis in the United States.

Chronic infections of hepatitis B (HBV) and hepatitis C (HCV) cause inflammation of the liver, which can cause cirrhosis and then develop into cancer. Approximately 25 percent of people diagnosed with hepatoma in the US display signs of a hepatitis B infection. Hepatitis C is most often associated with intravenous drug abuse, although the disease can also be spread through sexual contact. In regions of Africa and Asia, HCV and HBV combine to make liver cancer the most common cancer in those parts of the world.

A toxin, Aflatoxin is caused by a fungus that grows in tropical and subtropical zones. The fungus can be found on a number of foodstuffs, including wheat, rice, soybeans, tree nuts and peanuts. Long-term exposure to aflatoxin has been linked to liver cancer. In the US, the FDA limits the amount of aflatoxin that can be present in food.

Iron overload, or hemochromatosis, is a hereditary disorder that interferes with the body's ability to metabolize iron. Iron builds up to toxic levels in the body, especially in the liver where excess iron causes damage, inflammation and cell death. Iron overload can lead to cirrhosis.

The exact link between smoking and liver cancer is unclear, but studies point to a possible connection. Smoking appears to increase the risk: long-term smokers are at greater risk. The number of cigarettes consumed daily also appears to affect an individual's risk level.

A number of chemicals can act as hepatic carcinogens. Vinyl chloride, used to manufacture plastics, is one such carcinogen. Use of vinyl chloride is strictly controlled. Thorotrast® (thorium dioxide) was a dye used in contrast x-ray studies. Since its connection to hepatomas was discovered, its use has been discontinued. Drinking water contaminated with arsenic also increases risk levels in some geographic regions.

Older varieties of contraceptive pills were linked to a marginal increase in liver cancer risk. These pills are no longer used. Whether newer contraceptives can also cause hepatomas has yet to be determined, but any risk appears to be very low.

Long-term abuse of anabolic steroids causes a slight increase in the chances of developing hepatic cancer.

Resources

Action on Smoking and Health. (2004). Smoking and cancer.

American Cancer Society. (updated 2005). What causes liver cancer?

American Cancer Society. (updated 2005). What is liver cancer?

Frey, R.J. (2005). Liver cancer. Gale Encyclopedia of Medicine.

National Library of Medicine. (updated 2004). Hepatocellular carcinoma. MedlinePlus Medical Encyclopedia.

National Library of Medicine. (updated 2004). Liver metastases. MedlinePlus Medical Encyclopedia.

Worman, H. J. (2002). Hepatocellular carcinoma.