Between 1965 and 1977, there were 55 cases of testicular tumor at the Okayama University Hospital. The incidence of the disease was 0.30% of male outpatients, 1.77% of male inpatients and 5.94% of male patients with urogenital tumor. There were only 21 cases between 1955 and 1964, and it was considered that the incidence of the disease tended to gradually increase in recent years.
This opinion is supported by the report of the Japan Welfare Ministry, in which the number of the death cases with testicular tumor was 35 in 1947, 86 in 1957, 144 in 1967 and 202 in 1977. This statistical observation of death cases also indicated that elder age group (over 50 years old) showed a decreased incidence, but young adults showed a significantly increased incidence.
On the other hand, the incidence in children in Japan, which was higher than that in USA, remained stationaly in the observed periods. It showed a higher incidence of the testicular tumor under 2 years of age but a higher mortality over 2 years old, although embryonal carcinoma was a majority tumor in children under 3 years old.
