[Radiation reactions in the gonads: importance in patient counseling]

The intention of this article is to summarize the effects of radiation therapy on the female and male gonadal function.

In woman a decreasing tolerance to radiation is observed with increasing age, due to the decreasing number of follicles. The mean tolerance dose for sterilization is between 5 and 10 Gy. If both ovaries receive only scattered doses-radiation effects on the ovaries are dependent on the age of the women at the time of treatment. However, if both ovaries are included in the treatment volume of a tumor radiation therapy, sterilisation is unavoidable. In man even scattered doses are able to decrease the sperm cell counts in the range of 2 to 3 Gy in conventional fractionation regimes. Complete restoration of spermatogenesis is possible during the first 2 years after treatment, but is unlikely after 3 years. In contrast to the situation in female, impairment of male endocrine gonadal functions are observed only after testicular doses higher than 20 to 30 Gy. In female children the tolerance dose of the ovaries is higher than in the adult woman, while the gonadal endocrine function in boys is more sensitive than in adult men. In contrast, spermatogenesis is not initiated in young boys, and hence less radiation effects are induced.

In all treatment situations-in adults as well as in children-an additive effect of the combination of chemotherapy with radiation on gonadal function has been shown. However, the severity of damage by radio-chemotherapy is highly dependent on the drugs used.