Primary liver carcinoma and liver cirrhosis in atomic bomb survivors, Hiroshima and Nagasaki, 1961-75, with special reference to hepatitis B surface antigen.

During 1961-75, 128 cases of primary liver carcinoma (PLC) in the Radiation Effects Research Foundation life-span study extended sample and 301 cases of liver cirrhosis in the pathology study sample were observed. The presence of hepatitis B surface antigen (HBsAg) was assessed in all of the cases with the use of orcein and aldehyde fuchsin stains and was confirmed by the immunofluorescence technique. The incidence of PLC was two times higher in Nagasaki than in Hiroshima, which was statistically significant, but little difference was noted in the prevalence of cirrhosis in the two cities. Findings that might possibly explain the higher PLC incidence in Nagasaki were 1) the 2.3 times higher presence in Nagasaki than in Hiroshima of HBsAg in the livers of subjects without liver disease and 2) the two times higher prevalence in Nagasaki than in Hiroshima of cirrhosis with PLC. We believe that the higher incidence of PLC in Nagasaki is attributable to hepatitis B virus infection, although other factors (e.g., immunologic competence affected by radiation) cannot be excluded. In both cities, a suggestive relationship of radiation dose to cirrhosis prevalence, but not to PCL prevalence, was noted. To clarify possible radiation effects on cirrhosis prevalence, further follow-up of the populations of these two cities is necessary.