The following are the main risk factors for developing primary liver cancer.
Viral hepatitis — a disease that causes inflammation and can lead to cirrhosis, or scarring, of the liver — is the biggest risk factor for primary liver cancer. Hepatitis is caused most often by infection with hepatitis A, B, or C viruses; but only people with chronic, or persistent, hepatitis B or C infections and cirrhosis run the risk of developing liver cancer.
Viral hepatitis is very common. An estimated 350 million people worldwide, including 1.25 million Americans, have chronic hepatitis B. More than 170 million people (3 percent) worldwide and 2.7 million Americans have chronic hepatitis C. (The hepatitis C virus leads to chronic hepatitis in 60 to 85 percent of those infected.) Liver cancer usually develops two to three decades after a hepatitis infection has occurred. The incidence of liver cancer is on the rise in the United States and Europe despite a drop in hepatitis C infections. Widespread hepatitis B infections in Africa, China, and Southeast Asia have fueled an increase in the incidence of liver cancer throughout the developing world.
Known as a “silent” epidemic, viral hepatitis can be present in the body for years without causing pain or symptoms. Hepatitis B and C are spread through physical contact with blood or other bodily fluids of an infected person. Intravenous drug users may become infected by using unsterilized needles or sharing needles with others. Similarly, tattoos placed in the skin with unsterilized needles can lead to hepatitis infection. 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. Many people were infected through blood transfusions administered before 1992, before blood was routinely screened for the disease. A small number of cases are still associated with recent blood transfusions. These infections are considered so serious that the US Centers for Disease Control and Prevention issued guidelines in October 1998 that require hospitals to identify and notify anyone who may have received infected blood prior to 1992.
Alcohol Use or Abuse
Alcohol use or overuse also can increase a person’s chances of developing liver cancer. People with liver cirrhosis — an irreversible condition in which healthy liver cells are replaced by scar tissue — are at greater risk for developing liver cancer and should undergo regular screening, Cirrhosis can make surgical treatment of primary liver cancer more difficult.
Cirrhosis is commonly associated with alcoholism, although it may be caused by other conditions such as chronic hepatitis infection. Approximately 15 percent of all alcoholics will develop cirrhosis, but it is important to note that some people who develop cirrhosis are not alcohol abusers.
Alcohol consumption greatly increases the risk of developing cancer in patients who are carriers of the hepatitis B and C virus. Patients with viral hepatitis are strongly advised to refrain from consuming alcohol.
Non-Alcoholic Fatty Liver Disease (NAFLD)
NAFLD is a condition in which a type of fat, called triglycerides, accumulates in the liver. At its most severe, NAFLD can cause inflammation, cirrhosis, and liver failure. NAFLD is commonly seen in people who are morbidly obese and have type 2 diabetes. This condition is emerging as an important risk factor for liver cancer in the United States, where obesity is on the rise.
Other Risk Factors
Less common risk factors for liver cancer include exposure to arsenic in drinking water; certain chemicals in plastics; or abuse of anabolic steroids (a type of hormone that builds muscle) or male hormones. Smoking also may be linked to liver cancer. Although extremely rare in the United States, a 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 hemochromatosis (a relatively uncommon genetic disorder, most often found in people of Irish descent).
Avoiding exposure to the hepatitis B and C viruses is the most effective way to reduce your risk of developing liver cancer and/or cirrhosis. Doctors recommend that all children and adults receive the hepatitis B vaccine. (There is no vaccine for hepatitis C.) Hepatitis B may be treated with a combination of antiviral drugs such as interferon-alpha, lamivudine, and adefovir. Interferon-alpha and ribavirin are used to treat hepatitis C. In some cases, the virus can be completely eradicated from the bloodstream and eliminated from the body. If over time, however, the virus goes undetected and untreated, it can lead to very serious liver problems, including cirrhosis, liver failure, and eventually cancer.
Limiting alcohol consumption is another way that you can prevent liver cancer. As with most cancers, a healthy diet and regular physical exercise also can help lower your risk for developing this kind of cancer.
Hepatitis Screening & Treatment
People with active hepatitis B or C have the highest risk of developing liver cancer. These individuals may benefit from treating the hepatitis infection, as eradicating the virus may reduce their risk of developing liver cancer.
People who have received blood transfusions in the past or have a history of intravenous drug use may be unknowingly infected with hepatitis B or C, and should undergo screening to determine if they are infected. Hepatitis is diagnosed with blood tests specific for the hepatitis viruses. People who are diagnosed with hepatitis may be treated with antiviral medications.
Surveillance for Liver Cancer
People with a higher risk of developing liver cancer - including those with chronic hepatitis B or C, alcoholic cirrhosis, a family history of primary liver cancer or hemochromatosis, biliary cirrhosis, or alpha 1 antitrypsin deficiency — should see a liver specialist regularly for liver cancer surveillance. A blood test that measures levels of alpha-fetoprotein (AFP), a protein produced by the liver, is a sensitive test for liver cancer. Abdominal ultrasound imaging is another effective screening test for the early detection of primary liver cancer. When performed every six months, these tests can help identify liver cancer at an early, and treatable, stage in people with a higher risk of developing liver cancer.