The liver is the largest organ in the body, located below the right lung and divided into right and left lobes. It is composed of hepatocytes, cells that process nutrients in the blood.
It breaks down and stores many of the nutrients absorbed from the intestine and helps to remove toxic wastes from the body. It also makes bile, a fluid that helps to digest food, and produces proteins that help stop bleeding from cuts or wounds.
Types of Primary Liver Cancer
Most tumors in the liver actually start elsewhere in the body, such as in the colon or rectum, and spread to this organ (liver metastases) However, approximately 16,000 to 20,000 adults in the United States each year are diagnosed with cancer that originates in the liver, also known as primary liver cancer.
The most common type of primary liver cancer is hepatocellular carcinoma, which begins in hepatocytes and in many cases develops as a single tumor that spreads to other tissues and organs over time. Hepatocellular carcinoma is more common in men, and tends to affect people in their 60s and 70s.
The majority of Americans with hepatocellular carcinoma also have an underlying disease of the liver, such as illness related to hepatitis B or C infection, alcohol intake, or a metabolic abnormality such as non-alcoholic fatty liver disease or iron overload.
Primary liver cancer is far more common in areas of the world where there is a high prevalence of hepatitis B infection, such as in developing countries in sub-Saharan Africa and Southeast Asia. The number of cases has been increasing in the United States, however, due to a rising incidence of chronic hepatitis C and nonalcoholic steatohepatitis.
The second most common type of primary liver cancer is intrahepatic cholangiocarcinoma. While it is rare, the number of cases is increasing. The disease arises from bile duct cells within the liver, and is associated with the presence of certain conditions such as hepatitis B and C infection, primary sclerosing cholangitis (a disease that can lead to inflammation and obstruction of the bile ducts), and nonalcoholic steatohepatitis, or NASH (a disease that involves fat and inflammation in the liver that occurs in people who consume little or no alcohol).
Less common types of primary liver cancer include:
- Fibrolamellar-hepatocellular carcinoma (FLL-HCC), also called fibrolamellar carcinoma This rare subtype of hepatocellular carcinoma is less aggressive than other types of primary liver cancer and most often appears in people in their 20s and 30s. It is equally common in men and women. FLL-HCC is often confused with focal nodular hyperplasia, a type of benign liver tumor. Memorial Sloan Kettering is one of the few centers in the United States experienced in treating FLL-HCC.
- Angiosarcomas, Hemangiosarcomas, and Hemangioendotheliomas This type of tumor is a highly curable form of liver cancer that occurs almost exclusively in very young children. It usually is treated with surgery and chemotherapy.
This type of tumor is a highly curable form of liver cancer that occurs almost exclusively in very young children. It usually is treated with surgery and chemotherapy.
Benign (noncancerous) tumors also can form in the liver. Most do not cause symptoms and are discovered only when imaging tests are performed for another health condition. They may need to be treated if they cause bleeding, abdominal pain, or other significant symptoms. Tumors called adenomas, for example, carry a small risk of bleeding or developing cancerous changes, especially if they are large. Because of these risks, doctors sometimes recommend that they be treated.
Others common tumors of this type include focal nodular hyperplasia (a benign malformation of the liver), liver cysts, and hemangiomas.
Because liver cancer typically causes no symptoms in the early stages of the disease, the illness is often undetected until it has reached an advanced stage, when it is more difficult to treat. In fact, most cases of hepatocellular cancers in the United States are discovered during screening of at-risk individuals.
When symptoms do occur, they may include:
- Jaundice, a condition in which the skin and the whites of the eyes become yellow, urine darkens, and the color of stool becomes lighter than normal
- General feeling of poor health or weakness
- Loss of appetite and weight loss
- Swelling of the legs and abdomen
- Abdominal pain or discomfort