Michael C. Kew
Because of its frequency and grave prognosis, preventing hepatocellular carcinoma is an urgent priority. Prevention should be possible because environmental carcinogens-chronic hepatitis B and C virus infections, dietary exposure to aflatoxins, and iron overload-cause the great majority of these tumors. Chronic hepatitis B virus infection accounts for 55% of global hepatocellular carcinomas and 80% of those in the high-incidence Asia Pacific and sub-Saharan African regions. In these regions the infection that becomes chronic is predominantly acquired very early in life. A safe and effective vaccine against this virus is available and its universal inclusion in the immunization of infants has already resulted in a marked reduction of chronic infection and a 70% decrease in the occurrence of hepatocellular carcinoma in those immunized. Chronic hepatitis C virus infection is the major cause of hepatocellular carcinoma in industrialized countries. The infection is mainly acquired in adulthood and, until a vaccine becomes available, prevention will consist mainly of identifying, counselling, and treating chronically infected individuals, preventing spread of the virus by the use of safe injection practices (particularly in intravenous drug abusers), and screening all donated blood for the presence of the virus. 4.5 billion of the worlds population are exposed to dietary aflatoxins. Prevention involves treating susceptible crops to prevent fungal contamination, and handling the foodstuffs in such a way as to prevent contamination during storage. Iron overload in hereditary hemochromatosis can be prevented by repeated venesection and in African dietary iron overload by fermenting the home-brewed beer in iron-free containers.
Key words. Hepatitis B virus, Hepatitis B virus vaccine, Hepatitis C virus, Cirrhosis, Aflatoxin, Iron overload