Primary liver cancer (PLC) represents approximately 4% of all new cancer cases diagnosed worldwide. The purpose of this review is to describe some of the latest international patterns in PLC incidence and mortality, as well as to give an overview of the main etiological factors. We used two databases, GLOBOCAN 2002 and the World Health Organization (WHO) mortality database to analyze the incidence and mortality rates for PLC in several regions around the world. The highest age adjusted incidence rates (>20 per 100,000) were reported from countries in Southeast Asia and sub-Saharan Africa that are endemic for HBV infection. Countries in Southern Europe have medium-high incidence rates, while low-incidence areas (<5 per 100,000) include South and Central America, and the rest of Europe.
Cirrhosis is present in about 80โ90% of HCC patients and is thereby the largest single risk factor. Main risk factors include HBV, HCV, aflatoxin and possibly obesity and diabetes. Together HBV and HCV account for 80โ90% of all HCC worldwide. HBV continues to be the major HCC risk factor worldwide, although its importance will most likely decrease during the coming decades due to the widespread use of the HBV vaccine in the newborns. HCV has been the dominant viral cause in HCC in North America, some Western countries and Japan. Obesity and diabetes are increasing at a fast pace throughout the world, and if they are proven to be HCC risk factors, they would account for more HCC cases in the future.