Cohort Analysis of Incidence/Mortality of Liver Cancer in Japan through Logistic Curve Fitting


Incidence/mortality of liver cancer follow logistic curves because there is a limit reflecting the prevalence ofhepatitis virus carriers in the cohort. The author fitted logistic curves to incidence/mortality data covering thenine five-year cohorts born in 1911-1955 of both sexes. Goodness-of-fit of logistic curves was sufficiently preciseto be used for future predictions. Younger cohorts born in 1936 or later were predicted to show constant declinein incidence/mortality in the future. The male cohort born in 1931-35 showed an elevated incidence/mortalityof liver cancer early in their lives supporting the previous claim that this particular cohort had suffered massiveHCV infection due to nation-wide drug abuse in the 1950s. Declining case-fatality observed in younger cohortssuggested improved treatment of liver cancer. This study demonstrated that incidence/mortality of liver cancerfollow logistic curves and fitted logistic formulae can be used for future prediction. Given the predicted declineof incidence/mortality in younger cohorts, liver cancer is likely to be lost to history in the not-so-distant future.