I have chronic hepatitis C. I am curious about the different types of liver cancer and how they are linked to hepatitis.
Only one cancer that originates in the liver cells is common enough to be important: hepatocellular carcinoma, also called hepatoma. This cancer originates from the hepatocytes, the most numerous cells in the liver.
Many people, including doctors, use the term liver cancer, to describe any cancer that happens to be in the liver. In fact, at least in the U.S., most cancers in the liver are metastases — that is, cancers that originated in the colon, breast, lung, stomach, or kidneys and have traveled to the liver. The liver has a large blood supply from several sources; for some reason, cancer cells that drift there along with the blood find it easy to settle down and start to grow. Hepatocellular carcinoma, though, is a cancer that originates in the liver. It metastasizes to other organs, if not surgically removed in time.
Hepatocellular carcinoma is one of the most common cancers worldwide. It is especially prevalent in Asia and Africa, where chronic hepatitis B and C infection is common. Hepatocellular carcinoma due to chronic hepatitis B tends to occur at a younger age; many people in Asia and Africa acquire the virus from their mother at birth. Hepatitis C is more commonly acquired through blood or blood-product transfusion or through shared needle use, all activities that tend to occur later in life. Therefore the hepatocellular cancers attributed to hepatitis C tend to appear at a later age than those due to hepatitis B.
Analysis of the genes in hepatocellular cancers that develop in people infected with hepatitis B have shown that the hepatitis B genes have been incorporated into the cancer cells in the vast majority of cases. This cancer, therefore, joins cancer of the cervix and certain lymphomas on the list of cancers that are caused, at least in part, by viral infections.
Any liver disease that produces cirrhosis may lead to hepatocellular carcinoma: even alcoholism, where no virus infection is presumably present. Because the cancer tends to appear in a liver that is already cirrhotic, any early symptoms that it may produce, such as discomfort in the right upper abdomen, tend to be attributed to progression of the cirrhosis. Doctors have looked for better ways to follow people with these viral infections or cirrhosis, trying to catch the cancer at an early stage when it can be treated surgically.
A blood test — also called the alpha-feto protein test — will often be positive when hepatocellular carcinoma develops, but it tends to become positive too late and thus is not an effective screening device. Ultrasound of the liver has recently come into greater use, since it can detect quite small cancers. Studies in Asia of people infected by hepatitis B who were followed by serial — that is annual or every six months — ultrasound have shown a great improvement in five and ten-year survival after surgical removal of the tumors. Unfortunately, a similar study in Italy of patients infected with either hepatitis B or C did not prove as successful. The type of cancer that develops in Asians, most of whom are infected by hepatitis B at birth, may be somewhat different, perhaps easier to remove, than the type that develops in Europeans.