Primary prevention of hepatocellular carcinoma in developing countries

Hepatocellular carcinoma (HCC) is the fifth most common cancer in the world with 80% of cases occurring in developing countries. The cancer is rapidly fatal in almost all cases with survival generally less than 1 year from di agnosis. The major risk factors for this cancer have been identified as chr onic infection with hepatitis B (HBV) and hepatitis C (HCV) viruses and die tary exposure to aflatoxins. There is a safe and effective vaccine to preve nt chronic HBV infection. Given estimates that approximately 70% of HCC in developing countries is attributable to HBV then vaccination could prevent more than 250,000 cases per year in these areas of the world. A major chall enge now is to ensure the availability of vaccine in countries with endemic infection. Development of a vaccine against HCV is more problematic due to the genetic heterogeniety of the virus. However, with 24% of HCC in develo ping countries attributable to HCV (approximately 93,000 cases per year) a vaccine would make a major contribution to cancer prevention. Aflatoxins co ntaminate dietary staple foods (groundnuts, maize), are patent animal hepat ocarcinogens and are carcinogenic in humans with particularly high risks in individuals with a concomitant infection with HBV. Reduction of exposure c an be addressed at the community level either pre- or post-harvest by limit ing fungal contamination of crops; approaches may involve low technology po st-harvest measures to limit fungal growth or genetic engineering of crops to be resistant to fungal infection or toxin biosynthesis. An alternative m easure is to modulate the metabolism of aflatoxins once ingested using chem opreventive agents e.g., oltipraz. The resources available in countries wit h endemic hepatitis infection and fungal contamination of foods are often s everely Limited. Clearly HBV vaccination has to be the priority in the redu cing the incidence of HCC. However, there are currently 360 million chronic HBV carriers worldwide and HBV vaccine is still not incorporated into many national immunisation programs. Thus measures to reduce food spoilage by f ungi and the associated dietary exposure to aflatoxins is also a desirable public health goal. (C) 2000 Elsevier Science B.V. All rights reserved.