DES lead-in to use of luteinizing hormone releasing hormone analogs in treatment of metastatic carcinoma of prostate.

Luteinizing hormone releasing hormone (LHRH) analogs have been shown to be an effective alternative endocrine treatment of metastatic prostatic carcinoma. After a transient stimulation of testosterone (T) and dihydrotestosterone (DHT) during the first week of therapy, continued administration of LHRH analogs has reliably suppressed serum androgens to castrate levels. About 10 per cent of previously untreated patients begun on LHRH therapy will experience transient worsening of disease symptoms corresponding to the initial rise in androgen levels. In an attempt to eliminate the early rise of T and DHT, 9 patients with metastatic prostatic carcinoma were pretreated with diethylstilbestrol (DES), 3 mg/day, for one week prior to the initiation of LHRH therapy. Following this, both DES and LHRH were given concomitantly for a week, after which DES was discontinued. LHRH was then continued as long as patients experienced clinical benefit. T and DHT levels were performed pre-study and on days 4, 8-11, 13, 15, and 29 of study. Results indicate that pretreatment with DES did not completely prevent the rise in T and DHT seen during the first week of LHRH therapy, although T and DHT levels rose to only slightly above baseline during the first four days. T and DHT levels then markedly decreased, and castrate levels were achieved by day 29 of treatment.