Time trends in the incidence of testicular cancer in childhood and young adulthood.

BACKGROUND There has been a steep increase in the incidence of adult testicular cancer in many populations, but in spite of numerous studies, the etiology of testicular cancer remains elusive. The time trends of childhood testicular tumors are less clear and have been studied in a few populations. To further evaluate whether or not adult and childhood cancers share trend determinants and whether future adult testicular cancer incidences can be predicted through childhood testicular cancer incidences, their rates were compared. METHOD Data on testicular cancer incidence in childhood and in young adulthood were extracted from the IARC Cancer Incidence in the Five Continents Database limited to two 10-year time periods (1967-1976 and from 1987-1996) to allow for truncation-free analyses within the same birth cohort. RESULTS Childhood testicular cancer incidence varied 3- to 4-fold, whereas adult testicular cancer incidence varied 10- to 11-fold between the studied populations. No positive correlation between childhood and adulthood incidence of testicular cancer was found. CONCLUSION These data indicate that the incidence of testicular cancer in adulthood is influenced by factors, either prenatal or postnatal exposures different than those determining the trends among children.