Impact factors on development of cirrhosis and subsequent hepatocellular carcinoma.

Hepatocellular carcinoma (HCC), on the rise in many countries, is of multifactorial etiology. Its etiological associations differ between populations at high and low risk. Africans and Chinese have the highest incidence of HCC, but other affected groups include African Americans, Japanese, and Native Americans. Chronic infections by hepatitis B and hepatitis C viruses are major risk factors worldwide, although mechanisms through which the infections cause liver cancer are yet to be explained. Other documented risk factors have been postulated and include dietary exposure, cigarette smoking, alcohol consumption, diabetes, oral infection, and oral contraceptive use. In addition, many naturally occurring and synthetic chemicals to which humans are exposed via accidental contamination of food or water are shown to induce liver cancer in experimental animals. Consequently, assessment of possible human liver cancer risk associated with such exposures is complex. Early diagnosis and transplantation are the best treatments presently, although transplantation is not widely available due to donor shortage. Every effort should be directed toward the prevention of HCC, through the treatment and prevention of hepatitis and oral infections, prevention of chronic hepatitis progressing to cirrhosis, and prevention of the cirrhotic liver from developing HCC through chemopreventive modalities. However, at present, very few such studies exist.