Although liver cancer has a relatively low incidence in the United States, compared with other cancers, it is 10 times more common in many developing countries than in this country. The incidence of liver cancer is highest in sub-Saharan Africa, China, southern Asia, and Japan.
One of the most common forms of liver cancer, hepatocellular carcinoma, has been closely linked to the hepatitis B virus (HBV). The association between seropositivity for hepatitis B and the presence of hepatocellular carcinoma is strongest for children; almost 100% of children who have hepatocellular carcinoma test positive for the hepatitis B surface antigen (HBsAg). In contrast, 70% to 80% of adults with hepatocellular carcinoma are seropositive for hepatitis B.
The incidence of liver cancer is particularly high in Taiwan. Hepatocellular cancer ranks among the leading causes of morbidity and mortality: 1,000 people die of liver cancer and cirrhosis in Taiwan each year. Three million, or 15% of the population, are afflicted with cirrhosis and liver cancer.
There is also a high incidence of hepatitis B in Taiwan. Twenty years ago, the carrier rate of hepatitis B reached an estimated 15% to 20% of the general population of 21 millionone of the highest rates of hepatitis B in Asia.
Although the causal relationship between hepatitis B and hepatocellular cancer has never been established, public health officials in Taiwan and China instituted a nationwide hepatitis B vaccination program to decrease the incidence and carrier rate of hepatitis B, and, hopefully, simultaneously decrease the incidence of hepatocellular cancer.
Seventeen years after the initiation of the program, the prevalence of hepatitis B and the incidence of hepatocellular carcinoma in children age 6 to 14 years have decreased considerably.
Hepatitis B is transmitted from one person to another by blood transfusion, contaminated needle, sexual contact, and childbirth. More than 40% of infants born to HBsAg carrier mothers become HBsAg carriers themselves, indicating the frequent occurrence of mother-to-newborn transmission.