Epidemiology of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) affects more than half a million individuals per year worldwide. It is a largely preventable disease. Most cases are related to hepatitis B virus infection in sub-Saharan Africa and Eastern Asia (except Japan). Hepatitis C virus has emerged as an important cause of HCC particularly in North America and some parts of Europe, where a recent sharp increase in HCC has been reported. There is growing evidence of an association between obesity and diabetes and increased risk of HCC; however, the causal link is still unclear. The striking geographic and racial variations in the occurrence of HCC are partly explained by the distribution of HBV and HCV infections. Additional established risk factors for HCC include older age, male sex, heavy alcohol intake, aflatoxin exposure, iron overload related to hemochromatosis, and possibly tobacco smoking. The role of diet except for alcohol drinking and aflatoxin contamination in the etiology of HCC in human populations is largely unknown. Host genetic factors are being examined but definitive data are lacking. Most of these risk factors operate by promoting the development of cirrhosis which is present in most HCC cases. The annual risk of HCC in cirrhosis ranges between 1 and 7%. This review discusses in detail the epidemiology of HCC from a global perspective.