Attempted protection of spermatogenesis from irradiation in patients with seminoma by D-Tryptophan-6 luteinizing hormone releasing hormone.

Possible protective effects of D-Tryptophan-6 luteinizing hormone releasing hormone (D-Trp-6-LH-RH) against irradiation-induced testicular damage were investigated for the first time in patients with seminoma. After unilateral orchiectomy 12 men were allocated to receive the long-acting gonadotropin releasing hormone (GnRH) agonist D-Trp-6-LH-RH prior to and for the duration of radiotherapy. Eight patients with the same disease served as a control group. In contrast to several trials to protect spermatogenesis from chemotherapy by GnRH agonists, we first suppressed the pituitary-testicular axis before starting the treatment. As a new schedule this adjuvant GnRH agonist treatment was combined with cyproterone acetate for the first 20 days to diminish the amount and the duration of the initial stimulation of gonadotropins and testosterone. Irradiation started after suppression of the pituitary-gonadal axis. In all patients luteinizing hormone and testosterone were completely suppressed throughout the treatment compared to the controls, whereas the initial suppression of follicle-stimulating hormone was not completely maintained until radiotherapy was completed. At the follow-up at 18 months after completion of therapy, all patients reached their initial concentration of gonadotropins, testosterone, and motile spermatozoa independently of D-Trp-6-LH-RH treatment. With the dose and schedule investigated, the GnRH agonist showed no protective effects against testicular damage caused by radiotherapy.