Reviewed by Dr. Clement J. Cheng
The liver is the largest organ in the human body, weighing approximately three pounds. Its functions as an organ are to filter the blood that circulates in the body and to convert nutrients and drugs into chemicals for the body to use. Additionally, the liver removes toxins and waste products from the blood and prepares them for excretion. Its functions make it particularly open to cancer cells traveling in the bloodstream.
Primary liver cancer accounts for approximately 2 percent of all cancers in the United States, and perhaps half of all cancers in developing countries due to the high occurrence of hepatitis, a condition that may predispose a person to liver cancer. However, most liver cancer is secondary, which means that the cancer originated elsewhere in the body and spread to the organ. Liver cancer is more common in men than in women. The American Cancer society predicted about 15,300 new cases of liver cancer in the United States in 2000, with 13,800 people dying of the disease.
Liver cancer does not display early signs or symptoms, so in many cases it is not detected early. Due to the position of the liver in the body, under the rib cage, doctors cannot feel it for lumps. In addition, liver cancer progresses fairly quickly once it starts.
Four types of malignant liver tumors exist:
- Angiosarcoma—This is a rare type of liver cancer. It starts in the organ’s blood vessels.
- Cholangiocarcinoma—This tumor originates in the liver’s small bile ducts.
- Hepatoblastoma—This cancer is found most commonly in children and has a high recovery rate.
- Hepatocellular carcinoma (aka hepatoma or HCC)—This is the most common liver cancer, accounting for 84%. It begins in the hepatocytes, the main type of liver cell.
The cause of liver cancer is largely unknown. However, several risk factors are associated with it:
- Infection with hepatitis B or hepatitis C
- Cirrhosis of the liver
- Exposure to certain chemicals
