The liver is the largest organ inside your abdomen. It's found behind your ribs on the right side of your body.
The liver does important work to keep you healthy:
- It removes harmful substances from the blood.
- It makes enzymes and bile that help digest food.
- It also converts food into substances needed for life and growth.
The liver gets its supply of blood from two vessels. Most of its blood comes from the hepatic portal vein. The rest comes from the hepatic artery.
Cancer begins in cells, the building blocks that make up tissues. Tissues make up the organs of the body.
Normal cells grow and divide to form new cells as the body needs them. When normal cells grow old or get damaged, they die, and new cells take their place.
Sometimes, this process goes wrong. New cells form when the body doesn't need them, and old or damaged cells don't die as they should. The buildup of extra cells often forms a mass of tissue called a growth, nodule, or tumor.
Growths in the liver can be benign (not cancer) or malignant (cancer). Benign tumors are not as harmful as malignant tumors:
- are rarely a threat to life
- can be removed and usually don't grow back
- don't invade the tissues around them
- don't spread to other parts of the body
- may be a threat to life
- sometimes can be removed but can grow back
- can invade and damage nearby tissues and organs (such as the stomach or intestine)
- can spread to other parts of the body
Most primary liver cancers begin in hepatocytes (liver cells). This type of cancer is called hepatocellular carcinoma or malignant hepatoma.
Liver cancer cells can spread by breaking away from the original tumor. They mainly spread by entering blood vessels, but liver cancer cells can also be found in lymph nodes. The cancer cells may attach to other tissues and grow to form new tumors that may damage those tissues.
Liver Cancer: Who's at Risk?
When you get a diagnosis of cancer, it's natural to wonder what may have caused the disease. Doctors can't always explain why one person gets liver cancer and another doesn't. However, we do know that people with certain risk factors may be more likely than others to develop liver cancer. A risk factor is something that may increase the chance of getting a disease.
Studies have found the following risk factors for liver cancer:
Infection with hepatitis B virus (HBV) or hepatitis C virus (HCV): Liver cancer can develop after many years of infection with either of these viruses. Around the world, infection with HBV or HCV is the main cause of liver cancer.
HBV and HCV can be passed from person to person through blood (such as by sharing needles) or sexual contact. An infant may catch these viruses from an infected mother. Although HBV and HCV infections are contagious diseases, liver cancer is not. You can't catch liver cancer from another person.
HBV and HCV infections may not cause symptoms, but blood tests can show whether either virus is present. If so, the doctor may suggest treatment. Also, the doctor may discuss ways to avoid infecting other people.
In people who are not already infected with HBV, hepatitis B vaccine can prevent HBV infection. Researchers are working to develop a vaccine to prevent HCV infection.
Heavy alcohol use: Having more than two drinks of alcohol each day for many years increases the risk of liver cancer and certain other cancers. The risk increases with the amount of alcohol that a person drinks.
Aflatoxin: Liver cancer can be caused by aflatoxin, a harmful substance made by certain types of mold. Aflatoxin can form on peanuts, corn, and other nuts and grains. In parts of Asia and Africa, levels of aflatoxin are high. However, the United States has safety measures limiting aflatoxin in the food supply.
Iron storage disease: Liver cancer may develop among people with a disease that causes the body to store too much iron in the liver and other organs.
Cirrhosis: Cirrhosis is a serious disease that develops when liver cells are damaged and replaced with scar tissue. Many exposures cause cirrhosis, including HBV or HCV infection, heavy alcohol use, too much iron stored in the liver, certain drugs, and certain parasites. Almost all cases of liver cancer in the United States occur in people who first had cirrhosis, usually resulting from hepatitis B or C infection, or from heavy alcohol use.
Obesity and diabetes: Studies have shown that obesity and diabetes may be important risk factors for liver cancer.
The more risk factors a person has, the greater the chance that liver cancer will develop. However, many people with known risk factors for liver cancer don't develop the disease.
People who think they may be at risk for liver cancer should discuss this concern with their doctor. The doctor may plan a schedule for checkups.