Chronic Viral Hepatitis and Liver Cancer: From Infection to Cancer

Chronic viral hepatitis remains a major cause of primary liver cancer, specifically hepatocellular carcinoma (HCC), worldwide. Understanding and awareness of the link between viral hepatitis and liver cancer is vital in the prevention, early detection and treatment of chronic viral hepatitis and hepatocellular carcinoma.

Viral hepatitis is a viral infection that causes inflammation in the liver. There are five main types of hepatitis virus: hepatitis A, B, C, D and E. People infected with viral hepatitis may not be aware they have been infected because many people only experience mild or no symptoms. Many newly infected people will recover, but some people infected with hepatitis B, C or D can develop a life-long chronic infection that will put them at risk, sometimes years or decades later in life, to develop hepatocellular carcinoma or liver cirrhosis.

Hepatitis B and hepatitis C are recognized by the International Agency for Research on Cancer as human carcinogens. Chronic inflammation in some patients with chronic viral hepatitis can result in liver cell damage and cell death. Most cases of hepatocellular carcinoma in chronic viral hepatitis are associated with the body’s immune response, which is triggered to repair the chronic liver injury, resulting in liver fibrosis (scarring). Severe cases can result in cirrhosis, impaired liver function, and an increased risk of developing liver cancer due to DNA damage in rapidly regenerating liver cells. The majority of the chronic viral hepatitis patients who developed hepatocellular carcinoma have underlying cirrhosis. In patients with chronic hepatitis B infection, the hepatitis B viral DNA is integrated into the host liver cell genome, which can lead to mutations and the development of HCC. An estimated 10-20% of chronic hepatitis B patients who develop hepatocellular carcinoma do not have cirrhosis.

Chronic viral hepatitis infections cause prolonged inflammation of the liver, which damages hepatic epithelial cells. As the liver has a high regenerative capacity, this damage induces significant reproduction of more cells. At the same time, inflammation produces reactive oxygen species (ROS) and damages DNA, which increases the likelihood of DNA mutations. The combination of rapid cell growth and DNA mutation increases the chances of the cells becoming cancerous. Furthermore, liver inflammation causes changes in the liver's immune system, making cancer cells difficult to detect.

Prolonged inflammation caused by chronic viral hepatitis can also lead to cirrhosis, which is a major risk factor for liver cancer.

Now that we know chronic hepatitis is such a significant risk factor for developing liver cancer, it is important to be aware of the ways to prevent or manage viral hepatitis. Most of the deaths and complications related to chronic hepatitis B and C infection can be prevented through vaccination to prevent hepatitis B infection, a one-time universal screening of adults for chronic hepatitis B and C infection and curative antiviral therapy for chronic hepatitis C and long-term suppressive antiviral treatment for chronic hepatitis B.

Hepatitis B vaccination

The hepatitis B vaccine is the most effective way to prevent hepatitis B infection. Since it can prevent hepatitis B-related HCC, it is also called the first anti-cancer vaccine. Infections at an early age from perinatal transmission and early childhood from horizontal transmission carry the highest risk of developing chronic HBV infection. Both the World Health Organization and the U.S. Centers for Disease Control and Prevention recommend that all infants receive the first dose of the hepatitis B vaccine within 12 to 24 hours after birth and complete the vaccine series on schedule. Adults of all ages who have not yet been vaccinated or have not completed the vaccine series are also recommended to get the hepatitis B vaccine. Hepatitis B vaccination can also protect from hepatitis D, since hepatitis D can only infect people who are also infected with hepatitis B. Talk to a healthcare professional about your suitability for getting the hepatitis B vaccine.

Hepatitis B screening

The US Centers for Disease Control and Prevention recommends:

• Screening all pregnant women for hepatitis B in the first trimester of each pregnancy
• Screening all adults aged 18 years and older for hepatitis B at least once in their lifetime using a triple panel test
• Screening all infants born to HBsAg-positive mothers

Hepatitis B screening is also recommended for people with an ongoing risk of exposure.

• Having a history of sexually transmitted infections or multiple sex partners
• Having a past or existing hepatitis C infection
• Having human immunodeficiency virus (HIV) infection
• Having elevated liver enzymes (ALT levels)
• Sharing needles with or engaging in sexual contact with people who have a hepatitis infection
• Drug use or a history of injection drug use
• Not completing a hepatitis B vaccine series
• Receiving or have ever received maintenance hemodialysis
• Household contacts of people with known HBV infection

Hepatitis C screening

• The US Centers for Disease Control and Prevention recommends: Screening all pregnant women during each pregnancy
• Screening all adults aged 18 years and older

Screening is also recommended for people with the following risk factors:

• Received a transfusion of blood or blood products or an organ transplant before 1992
• Infants born to mothers with known hepatitis C
• Having human immunodeficiency virus (HIV) infection
• Drug use or a history of injection drug use
• Having elevated liver enzymes (ALT levels)
• Receiving or have ever received maintenance hemodialysis

Treatment

Chronic viremic hepatitis C can be cured in over 95% of cases with an oral antiviral medication taken once a day for 2-3 months. Although there is currently no cure for chronic hepatitis B, highly effective suppressive antiviral medication taken as simple as a pill a day can prevent disease progression and even reverse liver fibrosis and reduce the risk of HCC. Consult your doctor about treatment if you do have a chronic viral hepatitis infection. As it is a significant risk factor for liver cancer, it is crucial to get medical advice to manage or reverse the damage done to the liver due to a chronic viral hepatitis infection.