Hepatocellular carcinoma (HCC) is cancer that starts in the liver's main cells, called hepatocytes. It is the most common type of primary liver cancer — cancer that begins in the liver itself, rather than spreading there from another organ. HCC is diagnosed more often in men than women and is most often diagnosed in people age 50 or older.
HCC usually develops over years or even decades in someone who already has chronic liver disease. Cirrhosis, from any underlying cause, is the strongest risk factor and is present in more than 80% of people who develop HCC, and chronic hepatitis B or C infection also raises risk significantly.
Liver cancer is not one disease. Along with HCC, the other common type of primary liver cancer is cholangiocarcinoma, which starts in the bile ducts. Cancer that spreads to the liver from another organ, such as the colon or breast, is called metastatic liver cancer and is actually more common than cancer that starts in the liver itself.
Once HCC is identified, it can grow quickly, so how far it has spread at diagnosis makes a major difference in outlook and treatment options.