Risks and Prevention
A risk factor is anything that affects your chance of getting a disease, including liver cancer. Some risk factors, like smoking, can be changed. Others, like a person's age or family history, can't be changed.
But risk factors don't tell us everything. Keep in mind that 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.
Still, Providence Saint John’s liver cancer specialists have found several risk factors that make a person more likely to develop hepatocellular carcinoma (HCC).
Hepatocellular carcinoma is much more common in males than in females. The fibrolamellar subtype of HCC occurs in equal numbers in both sexes.
In the United States, Asian Americans and Pacific Islanders have the highest rates of liver cancer, followed by American Indians/Alaska Natives and Hispanics/Latinos, African Americans, and whites.
- Chronic viral hepatitis
The most common risk factor for liver cancer is long-term infection with hepatitis B virus or hepatitis C virus. These infections also lead to cirrhosis of the liver. People infected with both viruses have a higher risk of developing liver 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 neither is associated with an increased risk of liver cancer.
- Heavy alcohol use
Alcohol abuse is a leading cause of cirrhosis in the United States, which in turn is linked with an increased risk of liver cancer.
- 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.
Cirrhosis is a disease where liver cells become damaged and are replaced by scar tissue. People with cirrhosis have an increased risk of liver cancer. Most people who develop liver cancer already have some evidence of cirrhosis.
Being 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 be increased because people with type 2 diabetes tend to be overweight or obese, which can cause liver problems.
- Inherited metabolic diseases
Certain inherited metabolic diseases can lead to cirrhosis. For instance, people with hemochromatosis absorb too much iron from their food. The iron settles in tissues throughout the body, including the liver, and if enough iron builds up in the liver, it can lead to cirrhosis and liver cancer.
Other rare diseases that increase the risk of liver cancer include:
- Alpha1-antitrypsin deficiency
- Porphyria cutanea tarda
- Glycogen storage diseases
- Wilson disease
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. In the US, the content of aflatoxins are regulated through testing. Still, 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)
Vinyl chloride is a chemical used in making some kinds of plastics. Thorotrast is a chemical that was injected into some patients as part of certain x-ray tests. It is no longer used. However, past exposure to these chemicals raises the risk of angiosarcoma [link to types of tumors] of the liver. It also increases the risk of developing cholangiocarcinoma and hepatocellular cancer.
- 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.
Prolonged exposure to drinking water contaminated with naturally occurring arsenic can increase the risk of some types of liver cancer.
Avoid and treat hepatitis infections
The most significant risk factor for liver cancer is chronic infection with hepatitis B virus and hepatitis C virus. These viruses can spread from person to person through sharing contaminated needles and through unprotected sex, so some of these cancers may be prevented by not sharing needles and by using safer sex practices (such as consistent use of condoms).
A vaccine to help prevent hepatitis B infection has been available since the early 1980s. The U.S. Centers for Disease Control and Prevention (CDC) recommends that all children, as well as adults at risk (health care workers, those whose behaviors may put them at risk, etc.) get this vaccine to reduce the risk of hepatitis and liver cancer.
There are also a number of drugs can be used to treat chronic hepatitis B. These drugs have been shown to reduce the number of viruses in the blood and lessen liver damage. Although they do not cure the disease, they lower the risk of cirrhosis and might lower the risk of liver cancer, as well. More recently drugs have been shown to be very effective against the hepatitis C virus.
- Limit alcohol and tobacco use
Alcohol abuse is a major cause of cirrhosis, which can lead to liver cancer. Preventing liver cancers linked with alcohol abuse remains a challenge. Quitting smoking might also slightly lower the risk of liver cancer, as well as many other life-threatening diseases.
- Maintain a healthy weight
Avoiding obesity might be another way to help protect against liver cancer. People who are obese are more likely to have fatty liver disease and diabetes, both of which have been linked to liver cancer.
- Limit exposure to cancer-causing chemicals
Most developed countries also have regulations to protect consumers and workers from certain chemicals known to cause liver cancer. For example, the US Environmental Protection Agency (EPA) limits the allowable level of arsenic in drinking water in the United States. But this may continue to be a problem in areas of the world where naturally occurring arsenic commonly gets into drinking water.
- 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 at Saint Johns 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 primary liver cancer. Other blood tests such as carcinoembryonic antigen (CEA) can be elevated in colon cancer that has spread to the liver (colorectal liver metastases).
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.
Ask the liver cancer specialists at Providence Saint John’s Health Center for more information.