Liver Cancer: Risk Factors
The percentage of Americans diagnosed liver cancer has been rising slowly for several decades.
The American Cancer Society estimates there are about 33,000 new cases of liver cancer in the United States each year. Of these, 24,600 are found in men and 8,590 in women.
Primary hepatocellular carcinomas and bile duct cancers can affect patients of all ages, depending on their risk factors. For instance, patients with hepatitis B often acquire this infection at birth from their mothers; they tend to develop cancers at earlier ages than those with other risk factors, like hepatitis C.
Other risk factors include:
- Race/ethnicity Asians and people from sub-saharan Africa have the highest rates of hepatocellular cancer worldwide, because of the high incidence of hepatitis B infection in these populations. Bile duct cancers are also most common in parts of Asia where high rates of liver parasite infections are seen.
- Cirrhosis In this condition, liver cells are damaged and then replaced by scar tissue. The majority of people who develop liver cancer have a history of cirrhosis. Some types of autoimmune diseases can damage the bile ducts and lead to cirrhosis. People in this category have a high risk of both of the main types of liver cancer, HCC and cholangiocarcinoma
- Chronic viral hepatitis A long-term infection with hepatitis B virus (HBV) or hepatitis C virus (HCV) can lead to cirrhosis of the liver (see above) and eventually to liver cancer. Hepatitis C is the more common cause of HCC in the United States.
- Heavy alcohol use This is a common cause of cirrhosis leading to an increased risk of liver cancer.
- Obesity Non-alcoholic fatty liver disease, a condition in which people who consume little or no alcohol develop a fatty liver, is common in obese people and may lead to cirrhosis.
- Type II Diabetes Patients with type 2 diabetes can be more susceptible to liver problems, again usually through the development of inflammation, then cirrhosis
- Inherited metabolic diseases Patients with hereditary hemochromatosis absorb too much iron from their food. They also have a higher risk of developing cirrhosis and later, liver cancer. Other rare diseases that increase the risk of liver cancer include:
Porphyria cutanea tarda
Glycogen storage diseases
- Exposure to Vinyl chloride and Thorotrast Vinyl chloride, a chemical used in making some kinds of plastics, is now strictly regulated. Thorotrast is a chemical no longer used in certain x-ray tests.
- Anabolic steroids Anabolic steroids are male hormones are used by some athletes to increase strength and muscle mass. Long-term anabolic steroid use can slightly increase the risk of hepatocellular cancer.
- Arsenic Drinking water contaminated with naturally occurring arsenic increases the risk of some types of liver cancer.
- Parasites Various parasites can cause liver damage and the inflammation from these infections is linked to bile duct cancers. These parasites are not typically found in the US, but individuals traveling to Asia, Africa, and South America may be affected.
- Tobacco use Smoking has been linked to many forms of cancer, and is a risk factor for liver cancer.