Cancer starts when cells in the body begin to grow out of control. Cells in nearly any part of the body can become cancer, and can spread to other areas of the body. To learn more about how cancers start and spread, see What Is 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 necessary 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 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. The outlook for your health or your recovery (prognosis) depends on what type of tumor you have.
Cancers that start in the liver (primary liver cancers)
The place where a cancer starts is called the primary site, so cancers that start in the liver are known as primary liver cancers.
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. In this document the term liver cancer means hepatocellular carcinoma.
Bile duct cancer (cholangiocarcinoma)
Bile duct cancers account for 1 or 2 out of every 10 cases of liver cancer. These cancers can start in the small tubes (called bile ducts) that carry the bile that is made in the liver to the gallbladder or from the gallbladder to the intestines. For more information on this type of cancer, see Bile Duct (Cholangiocarcinoma) Cancer.
Rare types of primary liver cancers
Angiosarcomas and hemangiosarcomas 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.
Hepatoblastoma 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 the liver.
Cancers that spread to the liver (secondary liver cancers)
If a cancer starts somewhere else and then spreads to the liver, it is called secondary liver cancer. Secondary liver cancer is much more common than cancer that starts in the liver (primary liver cancer). Many common types of cancer, including colon, rectum, lung, and breast, spread (metastasize) to the liver. Secondary liver cancer is very different from primary liver cancer. The cancer cells still look and act like cancer cells from the part of the body that they came from, and they need treatments aimed at that kind of cancer, not liver cancer.
To learn more about cancer that has spread to the liver, see Advanced Cancer, as well as the document about the specific type of the primary cancer.
The rest of the information in this document refers only to hepatocellular carcinoma (HCC).
Last Revised: 02/23/2016