Turning points in time trends of cancer mortality in Japan: Premature mortality is more sensitive in the progress of cancer prevention

The aims of this study were to demonstrate the trend of overall mortality rate and premature mortality rate for select types of cancer in Japan and to assess the utility as a target indicator. The age-adjusted mortality rate for the total population (overall mortality rate) and that for persons under 65 years of age (under 65 mortality rate) for stomach cancer, liver cancer and lung cancer from 1950 to 1997 in Japan were calculated. Moreover, the turning point year of the mortality trend was estimated using a regression model of the rate of annual increase in each mortality rate. As the results show, a decline in the under 65 mortality rate preceding a decline in the overall mortality rate was observed in stomach cancer and male liver cancer. Also, the under 65 mortality rate due to lung cancer seemed to begin to decline in recent years for males, while the overall mortality rate has been increasing. This study suggests that the premature mortality rate is a more sensitive indicator of the effectiveness of cancer prevention. Hence, because of not only the larger burden of premature deaths, but also the sensitivity, premature mortality is considered to be suitable as a target indicator for cancer prevention strategies.