TRENDS IN INCIDENCE OF TESTICULAR CANCER IN NORWAY 1955-1992

The aim of this study was to explore the incidence of testicular cance r (TC) in Norway, and thereby to increase the understanding of aetiolo gical factors. From 1955 to 1992, a total number of 3927 TC cases were recorded in Norway, of which 51% were seminomas, 45% non-seminomas an d 4% other and unspecified types. The age-standardised incidence rate increased from 2.7 to 8.5 per 100 000. The age-specific incidence rate increased in all age groups, but was most marked in the younger popul ation. The significance of birth cohort as a risk factor for developme nt of TC was confirmed. The incidence by birth cohorts from 1916 to 19 70 showed an increase by later birth cohorts during the whole period, with the exception of a marked fall for the cohort born during the Sec ond World War. The largest increase occurred after the war. We conclud e that environmental factors acting very early in life are of signific ance in the development of TC.