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A risk factor is anything that increases your chance of getting a disease, such as cancer. Different cancers have different risk factors. Some risk factors, like smoking, can be changed. Others, like a person's age or family history, can't be changed.

But having a risk factor, or even several risk factors, does not mean that you will get the disease. And some people who get the disease may have few or no known risk factors.

Factors that can increase your risk of liver cancer

Several factors can increase a person's chance of getting a hepatocellular carcinoma (HCC).

Sex

Hepatocellular carcinoma is much more common in men than in women. Much of this is probably because of behaviors affecting some of the risk factors described below. The fibrolamellar subtype of HCC is more common in women.

Race/ethnicity

In the United States, Asian Americans and Pacific Islanders have the highest rates of liver cancer, followed by Hispanic and Latino, American Indians, Alaska Natives, African Americans, and White individuals.

Chronic viral hepatitis

Worldwide, the most common risk factor for liver cancer is chronic (long-term) infection with hepatitis B virus (HBV) or hepatitis C virus (HCV). These infections lead to cirrhosis of the liver and are responsible for making liver cancer the most common cancer in many parts of the world.

In the US, infection with hepatitis C is the more common cause of HCC, while in Asia and developing countries, hepatitis B is more common. People infected with both viruses have a high risk of developing chronic hepatitis, cirrhosis, and liver cancer. The risk is even higher if they are heavy drinkers (at least 6 alcoholic drinks a day).

HBV and HCV can spread from person to person through sharing contaminated needles (such as in drug use), unprotected sex, or childbirth. They can also be passed on through blood transfusions, although this is very rare in the United States since blood products are tested for these viruses. In developing countries, children sometimes contract hepatitis B infection from prolonged contact with family members who are infected.

HBV is more likely to cause symptoms, such as a flu-like illness and jaundice (a yellowing of the eyes and skin). But most people recover completely from HBV infection within a few months. Only a very small percentage of adults become chronic carriers (and have a higher risk for liver cancer). Infants and small children who become infected have a higher risk of becoming chronic carriers.

HCV, on the other hand, is less likely to cause symptoms. But most people with HCV develop chronic infections, which are more likely to lead to liver damage or even cancer.

Other viruses, such as the hepatitis A virus and hepatitis E virus, can also cause hepatitis. But people infected with these viruses do not develop chronic hepatitis or cirrhosis, and do not have an increased risk of liver cancer.

Cirrhosis

Cirrhosis is a disease in which liver cells become damaged and are replaced by scar tissue. People with cirrhosis have an increased risk of liver cancer. Most (but not all) people who develop liver cancer already have some evidence of cirrhosis.

There are several possible causes of cirrhosis. Most cases in the United States occur in people who abuse alcohol or have chronic HBV or HCV infections.

Non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease is a common condition in obese people. People with a subtype of this disease, known as non-alcoholic steatohepatitis (NASH), might go on to develop cirrhosis.

Primary biliary cirrhosis

Some types of autoimmune diseases that affect the liver can also cause cirrhosis. For example, in primary biliary cirrhosis (PBC) the bile ducts in the liver are damaged and even destroyed which can lead to cirrhosis. People with advanced PBC have a high risk of liver cancer.

Inherited metabolic diseases

Certain inherited metabolic diseases can lead to cirrhosis.

People with hereditary hemochromatosis absorb too much iron from their food. The iron settles in tissues throughout the body, including the liver. If enough iron builds up in the liver, it can lead to cirrhosis and liver cancer.

Heavy alcohol use

Alcohol abuse is a leading cause of cirrhosis in the US, which in turn is linked with an increased risk of liver cancer.

Tobacco use

Smoking increases the risk of liver cancer. People who smoked and stopped have a lower risk than those who still smoke, but both groups have a higher risk than those who never smoked.

Obesity

Being obese (very overweight) increases the risk of developing liver cancer. This is probably because it can result in fatty liver disease and cirrhosis.

Type 2 diabetes

Type 2 diabetes has been linked with an increased risk of liver cancer, usually in patients who also have other risk factors such as heavy alcohol use and/or chronic viral hepatitis. This risk may also be increased because people with type 2 diabetes tend to be overweight or obese, which in turn can cause liver problems.

Certain rare diseases

Diseases that increase the risk of liver cancer include:

• Tyrosinemia
• Alpha1-antitrypsin deficiency
• Porphyria cutanea tarda
• Glycogen storage diseases
• Wilson disease

Aflatoxins

These cancer-causing substances are made by a fungus that contaminates peanuts, wheat, soybeans, ground nuts, corn, and rice. Storage in a moist, warm environment can lead to the growth of this fungus. Although this can occur almost anywhere in the world, it is more common in warmer and tropical countries. Developed countries, such as the US and those in Europe, test foods for levels of aflatoxins.

Long-term exposure to these substances is a major risk factor for liver cancer. The risk is increased even more in people with hepatitis B or C infections.

Vinyl chloride and thorium dioxide (Thorotrast)

Exposure to these chemicals raises the risk of angiosarcoma of the liver (see What is liver cancer?). It also increases the risk of developing cholangiocarcinoma and hepatocellular cancer, but to a far lesser degree. Vinyl chloride is a chemical used in making some kinds of plastics. Thorotrast is a chemical that in the past was injected into some patients as part of certain x-ray tests. When the cancer-causing properties of these chemicals were recognized, steps were taken to eliminate them or minimize exposure to them. Thorotrast is no longer used, and exposure of workers to vinyl chloride is strictly regulated.

Anabolic steroids

Anabolic steroids are male hormones used by some athletes to increase their strength and muscle mass. Long-term anabolic steroid use can slightly increase the risk of hepatocellular cancer. Cortisone-like steroids, such as hydrocortisone, prednisone, and dexamethasone, do not carry this same risk.

Factors that may lower your risk of liver cancer

Hepatitis B vaccine

Since chronic hepatitis B infection can lead to cirrhosis and then liver cancer, getting vaccinated against the hepatitis B virus may protect people from liver cancer caused by the hepatitis B virus.

Treatment of viral hepatitis

It is known that chronic infections with hepatitis B or even hepatitis C can lead to cirrhosis and liver cancer. Getting treatment for either infection can lower one's risk of liver cancer.

Factors with unclear effects on liver cancer risk

Aspirin

Aspirin has been shown to reduce the risk of a few cancers. Some studies have shown a reduced risk of liver cancer with regular use of aspirin, but more research is needed.