Hormonal effects of cessation of estrogen treatment for prostatic carcinoma

Serum concentrations of testosterone, luteinizing hormone and follicle-stimulating hormone were measured before, and at 1, 12 and 24 months after cessation of long-term estrogen treatment (mean 8.7 years, range 4.3 to 13.1 years) in 14 patients with prostatic carcinoma but without metastases. In addition, the same hormones were measured before and up to 24 months after orchiectomy in 14 age-matched, previously untreated patients also without metastases. In long-term estrogen-treated patients serum concentrations of testosterone found at 1, 12 and 24 months after cessation of estrogen did not differ significantly either from the value before estrogen withdrawal or from the corresponding values found in age-matched patients after orchiectomy. The concentrations of luteinizing and follicle-stimulating hormones increased significantly in the estrogen-treated patients after cessation of estrogen and in the age-matched patients after orchiectomy. However, luteinizing and follicle-stimulating hormones were significantly lower in the patients after estrogen treatment than in the age-matched patients after orchiectomy. During the study period only 1 patient from the estrogen-treated group had clinical progression and he died of prostatic carcinoma. We conclude that long-term estrogen treatment causes impairment of Leydig cell function in patients with prostatic carcinoma and, as a result, the serum testosterone concentrations do not increase when that treatment is discontinued.