title: Trends in testicular cancer incidence in the Nordic countries, focusing on the recent decrease in Denmark.
abstract: Testicular cancer is the most frequent malignancy among young men, and there have been steady increases in its incidence in most western countries for many decades. Recently, a decrease was seen in some countries, including Denmark. Here, we report recent trends in testicular cancer incidence in the Nordic countries. We address the hypothesis that the causal factors for testicular cancer in Denmark are related to birth cohort and that non-seminoma and seminoma tumours have a common aetiology. An overall increase in testicular cancer incidence was found in the Nordic countries, corresponding to increases with each consecutive birth cohort in each country. In Denmark, a decline in incidence was observed during the past 5 years, and men born around 1943 and around 1968 showed lower incidences than men born just before or just after these dates. These birth-cohort effects were seen both for seminoma and non-seminoma tumours. This descriptive study confirms the hypothesis that birth cohort has a major influence on the incidence pattern of testicular tumours and suggests that seminoma and non-seminoma have common aetiological factors.
authors.affiliation: Institute of Cancer Epidemiology, The Danish Cancer Society, Copenhagen, Denmark. ruz@niph.dk
authors.forename: Rune
authors.initials: R
authors.lastname: Jacobsen
authors.forename: Henrik
authors.initials: H
authors.lastname: Møller
authors.forename: Steinar Ø
authors.initials: SØ
authors.lastname: Thoresen
authors.forename: Eero
authors.initials: E
authors.lastname: Pukkala
authors.forename: Susanne Krüger
authors.initials: SK
authors.lastname: Kjaer
authors.forename: Christoffer
authors.initials: C
authors.lastname: Johansen
mesh_terms: D015331:Cohort Studies; D003718:Denmark / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D008297:Male; D012042:Registries / Q000706:statistics & numerical data; D012189:Retrospective Studies; D012537:Scandinavian and Nordic Countries / Q000453:epidemiology; D018239:Seminoma / Q000453:epidemiology*; D013736:Testicular Neoplasms / Q000453:epidemiology*