Liver cancer refers to either primary liver cancer, that is cancer originating from the liver cells or supporting cells in the liver, or secondary liver cancer, that is cancer that has spread to the liver from the surrounding organs, usually via the blood that drains those organs and flow through the liver. In this article we shall confine ourselves to primary liver cancer, also referred to as hepatocellular carcinoma.
Liver cancer is one of the more commonly occurring cancers in the world, being the fifth most common cancer in men and the eighth most common cancer in women. The total number of new cases diagnosed is estimated to be about 500,000 every year. Men seem to be twice as likely as women to get liver cancer.
What could cause this problem?
The incidence of liver cancer seems to be higher in certain countries. Studies appear to indicate a positive relationship between the incidence of liver cancer and that of hepatitis B virus carrier states as well as hepatitis C virus infections. The risk of a hepatitis B carrier developing liver cancer is about 60 times higher than that of a non hepatitis B carrier. This risk appears to be even higher than the risk of a smoker developing lung cancer (about 20 to 25 times).
What countries have a higher incidence of hepatitis B carrier states? It is observed that certain countries seem to have a much higher incidence of hepatitis B carriers. One case in point is Taiwan, where it is noted that an abnormally high 20% of pregnant mothers were discovered to be carriers of hepatitis B. This compares significantly to the incidence of 1% in the United States. Similar studies show a higher incidence of hepatitis B carrier rates in South-East Asian countries, between 10% to 15%. This has led to the belief that Oriental persons are genetically less able to overcome the hepatitis B virus. This observation is supported by another observation, that the conversion rate to immunization with hepatitis B vaccine is lower in Chinese as compared with other races.
Studies also show that the incidence of new cases of primary liver cancer has decreased significantly in those countries where there has been a deliberate effort to immunize persons to hepatitis B with hepatitis B vaccine. This is one of the rare situations where there is a demonstrable cause/effect relationship, and where there is definite proof that a particular cancer can be prevented, by both vaccination and by screening of blood and blood products for hepatitis B and C viruses.
Other risk factors or suspected causes of liver cancer need to be mentioned here. They are:
Liver Cirrhosis. A situation of scarring of the liver due to chronic damage as a result commonly of heavy drinking. There is a slight increase of risk of liver cancer developing.
Inherited causes. Persons with hemochromatosis, a genetic problem of excess iron deposits in the body have a higher chance of developing liver cancer.
Aflatoxin. A mold found in bad peanuts and grain is a well known culprit in the causation of liver cancer.
