Commentary: Liver cancer and the epidemiological and cancer transition theories

in this issue investigates themost common form of liver cancer in Japan, hepatocellularcarcinoma (HCC). Using log-linear Poisson regression models andaddressing the problem of non-identifiability, the authors attemptto tease out the influence of age, period, and cohort effects on HCCmortality. An important conclusion of the article is that HCC deathrates are highest in cohorts born around 1930. Another conclusionat the opposite end of the spectrum also deserves to be stressed.That is, the lowest levels of HCC belong to the most recent cohorts.Hepatitis is spread by infection, and steep declines of HCC areexpected in 5–10 years in Japan largely because of the widespreadvaccination for hepatitis B virus and more recently institutedprograms screening donated blood (to be used in transfusions) forhepatitis C virus. Exploiting what is known about the successfullyimplemented public health efforts that have benefited more recentcohorts to try to make firmer predictions of future death rateswould make an additional useful contribution.In providing a context for the Shibuya and Yano piece, it isuseful to consider an extension of the epidemiological transitiontheory proposed by Gersten and Wilmoth.