What is liver cancer?
Liver cancer starts in the liver. To understand liver cancer, it helps to know something about how the normal liver looks and works.
About the liver
The liver is the largest organ inside the body. It lies under your right ribs, just below the right lung. The liver is shaped like a pyramid and is divided into right and left lobes.
Unlike most other organs, the liver gets blood from 2 sources. The hepatic artery supplies the liver with blood that is rich in oxygen. The portal vein carries nutrient-rich blood from the intestines to the liver.
You cannot live without your liver. It has many vital jobs:
- It breaks down and stores many of the nutrients absorbed from the intestine.
- It makes some of the clotting factors needed to stop bleeding from a cut or injury.
- It makes bile that goes into the intestine to help absorb nutrients.
- It filters out and breaks down toxic wastes in the blood, which are then removed from the body.
Because the liver is made up of different types of cells, many types of tumors can form in the liver. Some of these are cancer and some are not. Tumors that are cancer are called malignant. The medical word for tumors that are not cancer is benign. These tumors have different causes and are treated different ways. The outlook for your health or your recovery (prognosis) depends on what type of tumor you have.
Benign liver tumors
Benign tumors can sometimes grow large enough to cause problems. But they do not go into nearby tissues or spread to distant parts of the body. If they need to be treated, they can usually be cured by removing them with surgery. Please call us if you want to know more about the different kinds of benign liver tumors.
Cancers that start in the liver
Hepatocellular carcinoma (HCC)
This is the most common form of liver cancer in adults. It begins in the hepatocytes, the main type of liver cell. About 4 out of 5 cancers that start in the liver are this type. HCC can have different growth patterns.
- Some start as a single tumor that grows larger. Only late in the disease does it spread to other parts of the liver.
- Others seem to start in many spots throughout the liver, not as a single tumor. This is most often seen in people with ongoing liver damage (cirrhosis) and is the most common pattern seen in the United States.
Doctors can figure out the subtypes of hepatocellular cancer by looking at the cancer under a microscope. Most of these subtypes do not affect treatment or the patient's outlook. But one rare type, called fibrolamellar, can have a better outlook (prognosis) than other forms of liver cancer.
Bile duct cancer (cholangiocarcinoma)
Bile duct cancers account for 1 or 2 out of every 10 cases of liver cancer. These cancers start in the small tubes (called bile ducts) that carry bile to the gallbladder. They are often treated the same way as HCC. For more information on this type of cancer, please see our document Bile Duct (Cholangiocarcinoma) Cancer.
Cancers that begin in blood vessels in the liver (angiosarcomas and hemangiosarcomas)
There are rare cancers that start in the cells lining the blood vessels of the liver. These tumors grow quickly. Often by the time they are found they are too widespread to be removed. Treatment may help slow the disease, but these cancers are usually very hard to treat.
There is a very rare kind of liver cancer that is usually found in children younger than 4 years old. About 2 out of 3 children with these tumors have good outcomes with surgery and chemotherapy, although the tumors are harder to treat if they have spread outside of the liver.
Secondary liver cancer
Most of the time when cancer is found in the liver it did not start there, but started somewhere else (like the colon, breast, or lung) and spread to the liver. This is called metastatic cancer. Even though these cancer cells are in the liver, they still look and act like cancer cells from the part of the body that they came from. If someone has lung cancer that has spread to the liver, the cancer cells in the liver are still lung cancer cells, so the person will be treated for metastatic lung cancer.
To learn more about cancer that has spread to the liver, please see Advanced Cancer, as well as the document on the specific place where the cancer started.
The rest of the information here refers only to hepatocellular cancer (HCC).
Last Medical Review: 07/19/2012
Last Revised: 01/23/2013