Bilateral orchiectomy for carcinoma of prostate. Response of serum testosterone and clinical response to subsequent estrogen therapy.

Forty-five patients with symptomatic Stage D carcinoma of the prostate were treated with bilateral orchiectomy. Serum testosterone levels were obtained before orchiectomy, seven days after and a six-month intervals. With relapse after orchiectomy remission patients were treated with diethylstilbesterol (DES) 1 mg. daily. After bilateral complete orchiectomy 40 patients had serum testosterone levels in the anorchic range (21.5 to 39.7 ng./dl) while 5 had testosterone levels between 117 and 187 ng./dl. The mean remission response after orchiectomy was 9.1 months (three to twenty-four months) in the anorchic group and 9.4 months in the imcomplete anorchic group. Mean relapse response to estrogen therapy in the anorchic group was four months (one to six months). While in the incomplete anorchic group mean relapse response to estrogen therapy was 20.8 months (one to sixty). Serum testosterone levels in the imcomplete group decreased with estrogen therapy while those in the anorchic group were stable with estrogen therapy. Our findings suggest that bilateral complete orchiectomy does not always provide serum testosterone levels in the anorchic range. Subsequently these patients show an improved mean response to oral estrogen therapy.