Testicular cancer (TC) is the commonest malignancy in men aged 20 to 34 years. We reviewed the statistical sources of the IARC, and summarized the published studies on the increasing incidence rates of TC in the world.
We observed a variation of incidence rates according to the geographical situation. The majority of industrialized countries, North-America, Europe, and Oceania showed higher incidence rates than Asian or African countries. Nevertheless, surprising differences in TC incidence rates were observed between neighboring countries and also between different regions in the same country. Substantial differences in TC incidence were also observed between ethnic groups.
A clear trend towards an increase in TC incidence over the last decades was revealed. The increase in TC incidence was associated with a strong birth cohort effect in the USA, and also in European countries.
Previous studies have not been able to explain the variation of worldwide incidence rates and its increase. Although male reproductive abnormalities assumed to be related to exposure to high levels of endogenous oestrogens during pregnancy, further studies are required before any conclusions can be drawn.