Background: Hepatitis B virus infection is one of the most important risk factors for hepatocellular carcinoma.Hepatitis B vaccination has been obligatory in the Expanded Program on Immunization (EPI) in Khon Kaensince 1990.
Objective: To compare the incidence of hepatocellular carcinoma in children in Khon Kaen provincebefore and after the introduction of national hepatitis B vaccination program.
Methods: Cases of liver tumors inchildren under 18, diagnosed during 1985-2007, were retrieved from the population-based cancer registry ofKhon Kaen. Patients were divided into 2 groups, vaccinated and non-vaccinated with hepatitis B vaccine regardingthe year of birth before or after 1990. Patients with diagnosis of liver cancer from any basis of diagnosis inpopulation-based registration, except hepatoblastoma, were included. Patients without verified histology wereassumed as having hepatocellular carcinoma if the age at diagnosis was over 10. Age-standardized incidencerates (ASRs) were analyzed and expressed as numbers per 1,000,000 population.
Results: Fifteen patients aged13 to 18 years were included to this study. The mean and median ages at diagnosis were 15.7 and 15 yearsrespectively. Four children had a verified histology (age 14 to 18 years, median and mean = 16). The remaining11 patients were diagnosed based on history & physical examination, radiology and death certificate, at theaged of 13 to 18 years. The ASRs for liver cancer in children over 10 years of age of non-vaccinated and vaccinatedchildren were 0.88 and 0.07 per million respectively (p = 0.039). When calculated by including children at orolder the 5 years of age, the ASRs for non-vaccinated and vaccinated cases were 0.97 and 0.24 per millionrespectively (p = 0.007).
Conclusions: The incidence of hepatocellular carcinoma is significantly lower in Thaichildren who receive hepatitis B vaccine at birth.