In Africa and South East Asia the incidence is 20-30 times greater and is associated with chronic liver disease secondary to Hepatitis B and C infection. The natural carcinogen aflaxtoxin is also associated with hepatocellular carcinoma. This toxin is a product of the aspergillus fungus which thrives in hot, humid conditions and may commonly be seen as a white layer on the surface of stored rice. It is classified into intrahepatic and extrahepatic lesions. Intrahepatic lesions are locally invasive and have a poor prognosis, with a survival time of 3-6 months from diagnosis.
Extrahepatic lesions are locally invasive and metastasise late.
However, as they invade the liver, portal vein and hepatic arteries at an early stage these tumours are not usually curable. They can arise from any primary tumour, but are particularly common in cancers of the gastro-intestinal tract, of the breast and of melanocytes. Most liver metastases are asymptomatic and therefore can be extensive prior to diagnosis. For curative treatment to be possible, metastases need to be found while they are small and asymptomatic . The only curative treatment is surgery.