Comparison between Overall,Cause-specific,and Relative Survival Rates Based on Data from a Population-based Cancer Registry

Three kinds of survival rates are generally used depending on the purpose of the investigation: overall,cause-specific, and relative. The differences among these 3 survival rates are derived from their respectiveformulas; however, reports based on actual cancer registry data are few because of incomplete information andshort follow-up duration recorded on cancer registration. The aim of this study was to numerically and visuallycompare these 3 survival rates on the basis of data from the Nagasaki Prefecture Cancer Registry. Subjectswere patients diagnosed with cancer and registered in the registry between 1999 and 2003. We calculated theproportion of cause of death and 5-year survival rates. For lung, liver, or advanced stage cancers, the proportionsof cancer-related death were high and the differences in survival rates were small. For prostate or early stagecancers, the proportions of death from other causes were high and the differences in survival rates were large.We concluded that the differences among the 3 survival rates increased when the proportion of death from othercauses increased