When talking about cancer of the liver it is very important to be clear about the difference between primary and secondary cancer.

A primary cancer is one which starts in a particular part of the body, a secondary cancer is one which spreads to that part of the body from a cancer elsewhere. Primary liver cancers are quite uncommon in the UK, with less than 1,000 new cases each year, making up fewer than 1 in every 100 cancers diagnosed.

Four out of five cases of primary liver cancer occur as a complication of cirrhosis of the liver. Overall about 1 in 20 people who develop cirrhosis will eventually get a primary liver cancer.

The commonest cause of cirrhosis leading to primary liver cancer is viral hepatitis, with hepatitis B and hepatitis C. This can lead to chronic (long-term) hepatitis, which in turn leads to cirrhosis and eventually to primary liver cancer. This is usually a very slow process and it can often take 30 years from the initial viral infection to the development of the liver cancer.

People who have cirrhosis and who also drink a lot of alcohol are more at risk than non-drinkers who have cirrhosis.

There is an uncommon illness called haemochromatosis, where excessive amounts of iron are stored in the liver, and this can occasionally lead to the development of primary liver cancer.

In some parts of Africa and Asia poor storage of crops can lead to them being infected by a fungus called Aspergillus flavus. This produces a poison called aflatoxin, and eating foods contaminated by aflatoxin can lead to primary liver cancer in these countries.