Childhood cancer in Sweden, 1958-1974. I. Incidence and mortality.

All cases of tumours and tumour-like conditions in children 0-14 years reported to the Swedish cancer registry during the period 1958-74 have been studied. The material consists of 3797 individuals on file in this registry. The most common cancer diagnoses in children 0-14 years are leukemia and tumours of the central nervous system (together constituting approximately 58% of all cases). Almost half of the cancers affect children below five years of age. The lowest incidence occurs in the ages 7-8 years, and the highest occurs during the first year of life. The types of tumours below one year of age show a different distribution than in any other age groups. A significant increase in the incidence of childhood cancer occurred, while the mortality rates showed a slight decrease during the period studied. A remarkable increase in the incidence figures was noted concerning tumours of the nervous system, especially in boys. The decrease in the mortality rates was most obvious regarding Wilms' tumour, and leukemia in children 0-4 years of age.