What is Liver Cancer?
Cancer begins when abnormal cells grow out of control and invade other tissues in the body and continue to multiply. Many different cancers can affect the liver. Cancer of the liver can originate in the liver itself (primary liver cancer) or originate in other parts of the body, then spread to the liver through the bloodstream (metastatic cancer).Types of primary liver cancer:
- Hepatocellular carcinoma (HCC) (also called hepatoma because it comes from hepatocytes, the main type of liver cells). HCC is the most common form of primary liver cancer in children and adults and one of the most frequently occurring cancers in the world. Some hepatocellular cancers begin as a single tumor that grows larger and spreads to other parts of the body late in the disease. Other hepatocellular cancers begin as many, small cancer nodules throughout the liver, rather than a single tumor and is seen predominantly in people with chronic liver damage (cirrhosis).
- Intrahepatic cholangiocarcinoma . Also known as bile duct cancer, this cancer can appear in both the liver and the bile ducts outside the liver. Bile ducts are tubes that carry bile to the gallbladder. Seen mostly in older people (average age of 73), about 2,000 to 3,000 people in the United States develop bile duct cancer.
- Hepatoblastoma . This rare type of cancer essentially develops only in children usually before the age of four years. If diagnosed early, the survival rate is high for children with hepatoblastoma. However, for hepatoblastomas that are large or have spread beyond the liver, prognosis is poor.
About Metastatic Cancer
Metastatic cancer (secondary liver cancer) is not actually known as liver cancer. Most cancer that occurs in the liver begins in another part of the body. Some of the most common cancers that metastasize to the liver are those originating in the colon, pancreas, lung and the breast. These cancers are named after the organ in which the cancer originated. So cancer that starts in the colon and spreads to the liver is known as metastatic colon cancer, not liver cancer. Lymphomas and leukemias, cancers that originate in the lymph nodes and bone marrow, respectively, can also invade the liver. In the United States and Europe, secondary (metastatic) liver tumors are more common than primary liver cancer. The opposite is true for many areas of Asia and Africa.
According to the American Cancer Society's most recent estimates, there are about 24,120 new cases of primary liver cancer and bile duct cancer in the United States and about 18,910 deaths from these cancers.