Trends in incidence of testicular cancer and prostate cancer in Denmark.

This article presents a detailed analysis of the incidence trends of testicular cancer and prostate cancer, using information from the Danish Cancer Registry in the period 1943-1996. The rate of increase of testicular cancer was about 2.6% per year. The analyses indicated that incidence was more strongly dependent on the man's birth cohort than on the calendar period. The analysis confirmed the significantly reduced incidence of testicular cancer in the 1943 cohort and suggested a levelling off in the increase in testicular cancer incidence from cohorts born after around 1963. This may imply that the great part of the recent increase in incidence has been due to a rapid increase in incidence in successive birth cohorts born in the relatively short period from 1945 to 1960. The rate of increase of prostate cancer was about 1.6% per year. The analyses indicated a stronger dependency on period than on birth cohort. The cohort parameters had very low values in the three earliest cohorts (1858-1868) and the period parameters showed a low incidence in the most recent period. The epidemiological pattern of prostate cancer incidence seems dominated by changes in diagnosis and registration and does not permit inferences about changes in causal factors.