The five main risk factors for liver cancer are:
- chronic viral hepatitis
- alcohol use or abuse
- inherited metabolic diseases that affect the liver
- environmental factors
- physical conditions, such as obesity or diabetes
Hepatitis
Viral hepatitis -- which is a disease of the liver causing inflammation -- is the most common risk factor for hepatocellular cancer. The most common hepatitis viruses are hepatitis A, B, and C, but only people with chronic, or recurring, cases of hepatitis B or C run the risk of developing liver cancer or cirrhosis.
The number of people with viral hepatitis is extremely high, and incidence of liver cancer is on the rise, particularly in Africa, China, and Southeast Asia. It is estimated that 1.25 million people have chronic hepatitis B in the United States and 350 million are infected worldwide. As many as four million people are infected with hepatitis C; more than 2.7 million Americans and 170 million individuals in the world (or three percent worldwide) are chronically infected. The hepatitis C virus leads to chronic hepatitis in 55 to 85 percent of those infected.
People contract hepatitis B or C through physical contact with blood or other bodily fluids of an infected person. Those engaging in unprotected sex, sharing needles, or living with people who are infected with hepatitis B or C are at an increased risk of developing the virus. Also at risk are people who received blood transfusions administered before 1992 (before screening was mandatory).
Prevention or early treatment of chronic hepatitis B and C can decrease the chances of developing liver cancer and/or cirrhosis. There is a vaccine for hepatitis B, and anyone who might be exposed should be vaccinated. Doctors recommend that anyone who has chronic hepatitis B or C should be screened for liver cancer.
Alcohol Use
Alcohol use or overuse can also increase a person's chances of developing liver cancer. People with cirrhosis -- an irreversible condition in which healthy liver cells are replaced by scar tissue -- are at particular risk for developing liver cancer and should be regularly screened for cancer. Cirrhosis can develop from any of the first four risk factors listed above, but it is commonly associated with alcoholism. Approximately 15 percent of all alcoholics will develop cirrhosis of the liver, but it is important to note that some people who develop cirrhosis are not alcohol abusers. Cirrhosis makes the surgical treatment of primary liver cancer more difficult.
Other Factors
Other factors, such as environmental and physical conditions (obesity and diabetes, for example), add to the risk of developing liver cancer. Although extremely rare in the United States, a type of food contaminant called aflatoxin (a harmful substance made by certain types of mold that is often found on poorly stored grains and nuts) increases a person's risk for primary liver cancer, as do metabolic or genetic diseases such as hematomacrosis (a relatively uncommon genetic disorder, most often found in people of Irish descent).
For more information about ways to prevent liver cancer, see the Prevention section of this overview.
