EVALUATION OF THE DEATH CERTIFICATE FOLLOW-UP METHOD FOR THE ANALYSISOF SURVIVAL RATE - DATA FROM AICHI PREFECTURE, JAPAN

To evaluate the use, for studies ore survival, of death certificates f rom population-based cancer registries in Japan, we compared 5-year su rvival rates by two different: methods: passive, derived from death ce rtificates, and active, using family register systems. Registered canc er cases from Aichi Prefectural Cancer Registry were used as a model. The study subjects comprised 9244 cancer patients (3830 males and 5414 females) newly diagnosed at the Aichi Cancer Center Hospital and reco rded in the Aichi Prefectural Cancer Registry between 1983 and 1991. T he passive follow-up method, using death certificates, identified 87-8 9% of deaths among the study subjects. The proportion of deaths which were not identified by the passive follow-up method did not vary great ly with age or gender, but was higher among patients in the earlier ra ther than the later stages of cancer. Overall, the absolute and relati ve effects sf unregistered deaths on apparent survival rate vary; with the absolute survival rate. The absolute and relative differences bet ween the survival rates calculated by the two methods are explained mo re clearly when data are analyzed by cancer site. The results of the p resent study provide useful information far interpreting the survival rate following diagnosis of cancer estimated by the passive follow-up method, i.e. using death certificates from a population-based cancer r egistry.