Trends in testicular germ cell cancer incidence in Australia

Abstract

Objective: Although increasing incidence of testicular
germ cell cancer has been reported in many developed
nations, national estimates for Australia, with histological
differentiation, are not currently available.-----
Methods: Using data from all state and territory population-
based cancer registries in Australia, this paper reports
on incidence trends for seminomas and non-seminomas in
Australia between 1982 and 2004 using Joinpoint and Age–
Period–Cohort models.-----
Results: Of the 10,528 testicular germ cell cancers diagnosed
during this period, 6086 (58%) were seminomas.
Incidence rates have increased (2.6% per year) in Australia
since 1982, with the effect stronger among seminomas
(3.4% per year) rather than non-seminomas (1.4% per
year). There was a strong age effect evident for both subtypes,
peaking in the 25–29 year age group for nonseminomas
and the 30–34 year age group for seminomas.
Non-seminoma rates reflected a significant birth cohort
effect, following a U-shaped pattern with the lowest risk
among the 1,945 birth cohort.-----
Conclusions: The differential trends observed for Australia
for seminomas and non-seminomas are consistent
with those reported for the United States, but slightly
different to those reported for Europe. The trends may
be at least partly due to changes over time in the
prevalence of etiologic or protective factors around the
time of birth.