Chronic Viral Hepatitis
Worldwide, the most common risk factor for liver cancer is chronic infection with the hepatitis B virus. Chronic viral hepatitis infections (hepatitis B and hepatitis C) cause at least 80% of all liver cancers. In the United States, the leading cause is chronic hepatitis C virus infection because of the greater number of Americans infected with this virus. Globally, however, chronic infections with hepatitis B or C are responsible for making liver cancer the most common cancer in many parts of the world.
More than 50% of all liver cancers could be prevented with increased use of the hepatitis B vaccine, better treatments for chronic hepatitis B, and curative treatments for hepatitis C infections.
Hepatitis B Infections
The hepatitis B virus is classified by the International Agency for Research on Cancer as a known cancer-causing virus in humans because of the strong link between chronic hepatitis B infection and liver cancer. People chronically infected with hepatitis B are 100 times more likely to develop liver cancer than uninfected people because the virus directly and repeatedly attacks the liver. These attacks over time can lead to increasing liver damage, cirrhosis (scarring of the liver), and ultimately, liver cancer.
Among people chronically infected with hepatitis B, the risk of developing liver cancer increases as they get older or if they have been diagnosed with cirrhosis. Additional risk factors for liver cancer include a family history of liver cancer, persistence of high hepatitis B DNA levels, and co-infection with HIV or hepatitis C or D.
Although liver cancer most often occurs in the presence of cirrhosis, individuals with chronic hepatitis B infection can develop liver cancer without having cirrhosis. This is why regular liver cancer screening is so important (see Who Should Be Screened).
To learn more about the prevention and treatment of chronic hepatitis B infections, visit www.hepb.org.
Hepatitis C Infections
Chronic hepatitis C infections cause cirrhosis (scarring of the liver), which can lead to liver cancer. The number of cases of liver cancer is increasing in Western Europe, North America, and the Pacific Islands. This increase may be related to the growing number of people being diagnosed with chronic hepatitis C infection. The number of liver cancer cases related to hepatitis C infections is predicted to continue rising and could possibly double over the next 10 to 20 years.
In the United States, hepatitis C infection is the most common cause of liver cancer due to the greater number of Americans infected with this virus, while in Asia and sub-Saharan Africa, chronic hepatitis B infections are the most common cause. People co-infected with hepatitis B, hepatitis C, or HIV have a significantly increased risk of developing liver damage, cirrhosis, and liver cancer. To learn more about the prevention and treatment of hepatitis C, visit our Resources page for links to nonprofit organizations that provide valuable information and support.
Hepatitis D Co-infections
Hepatitis D is the most severe form of viral hepatitis and can only exist as a co-infection of hepatitis B, making all hepatitis B patients at risk. Coinfections can increase the risk of cirrhosis and liver cancer by up to three times compared to a hepatitis B infection alone. Coinfections are important to identify due to the need to alter management and treatment strategies.
Globally, hepatitis D is estimated to affect 15-20 million people, or about 5-15% of all people infected with hepatitis B. Hepatitis B and D co-infection is more common in some parts of the world such as China, Russia, the Middle East, Mongolia, Romania, Georgia, Turkey, India, Pakistan, Africa, and the Amazonian river basin.
If you have hepatitis B, talk to your doctor about your risk for hepatitis D. To learn more about this dangerous co-infection, and the prevention and treatment of hepatitis D, visit our Hepatitis Delta Connect website.