Localized Irradiation of Testes with Carcinomain Situ: Effects on Leydig Cell Function and Eradication of Malignant Germ Cells in 20 Patients*

Twenty men (median age, 31 yr) previously treated for unilateral testicular cancer received localized irradiation in a dose of 20 Gray in 10 fractions for carcinoma in situ of the remaining testis. Follow-up testicular biopsies performed 3 (n = 19) and 24 (n = 14) months after the treatment showed in all cases a Sertoli cell-only pattern. Hormonal evaluation was performed before as well as 3, 12, 24, and 36 months after radiation treatment. Endocrine parameters were followed for a median of 30 months (3-36 months). Baseline serum testosterone values decreased during the follow-up period from 13.3 +/- 6.0 to 10.8 +/- 6.4 nmol/L (mean +/- SD), although the decrease was not statistically significant (P = 0.06). Serum LH values increased during the first 3 months of follow-up from 10.4 +/- 5.4 to 15.6 +/- 7.3 IU/L (P less than 0.0001) and then remained unchanged. Significant decreases in GnRH- and hCG-stimulated testosterone levels also indicated an impairment of Leydig cell function. FSH levels increased (P less than 0.0001) during the first 3 months of follow-up from 21.8 +/- 11.1 to 33.2 +/- 13.2 IU/L. We conclude that localized irradiation of 20 Gray eradicated carcinoma in situ germ cells. Development of a second testicular cancer has until now been prevented. Leydig cell function was partially impaired by the radiation dose given.