Abstract
Mortality for childhood cancer has declined in Osaka, as well as all over Japan, since the 1970s, but whether this decline can be explained by trends of incidence or survival of childhood cancer has not been examined. A total of 5960 malignant tumors diagnosed between 1973 and 2001 in children <15 years of age were registered at the Osaka Cancer Registry in Japan. The time trends for childhood cancer were analyzed over 29 years for incidence and 20 years for survival. Leukemia was the most common among childhood cancer for both sexes and accounted for one-third of all cases. The age-standardized annual incidence rate of all tumors was highest in 1988-1992: 155.1 per million for males and 135.9 for females. Five-year survival for all tumors improved from 50.1% in 1978-1982 to 73.0% in 1993-1997 for males and from 52.3% to 76.3% for females. Thus, the constant decline in mortality in childhood cancer was primarily due to improved survival between the 1970s and 1980s and reduced incidence after the 1990s.