Introduction

Testicular cancers are relatively uncommon and occur primarily in white males under the age of 50. They are very rare in Africans and Asians.

Histology, classification and diagnosis

While testicular germ cell cancers predominate, a range of histological types are described by Mostofl (1977) and Schottenfeld and Warshauer (1982). About 50% of tumors are seminomas, 40% embryonal carcinomas and 6% teratomas.

Descriptive epidemiology

Incidence

The upper range of rates, between 3 and 9, is generally seen in western European countries. Although the highest rates occur in Switzerland (8.3 in Basel; 9.9 in urban Vaud) and in Denmark (7.8), a high rate is also seen in the Maoris (7.9) of New Zealand. Blacks in the USA, with rates around unity, have a much lower incidence than whites, with rates in the range of 3 to 5. The reported incidence of testicular cancer is even lower for African blacks than for American blacks (Fig. 46.1). Despite the accessibility of this site, several reports from Africa (Parkin, 1986) do not describe any such tumors, in contrast to penile cancer. Most rates in Asia are below unity. In several European countries, notably Denmark, the cancer is increasing in incidence.

Mortality rates for the highest socio-economic classes have been shown to be twice those in the lowest (Logan, 1982).

Etiological inferences

While geographical variations and higher rates in the upper social classes suggest that environmental factors may play some role, the great rarity of this cancer in both North American blacks and Africans suggest that an ethnic factor may be involved.