WITHDRAWAL PHENOMENON WITH THE ANTIANDROGEN CASODEX

Total androgen blockade with castration and antiandrogens has become t he primary therapy in metastatic prostate carcinoma. Several reports h ave been published on the flutamide withdrawal syndrome with a favorab le response in patients with progression of disease after lengthy remi ssion while taking combined hormone therapy. The experience with withd rawal of the experimental nonsteroidal antiandrogen casodex dagger in 3 patients is reported. All patients received casodex monotherapy init ially, then luteinizing hormone-releasing hormone analogues were added on progression of disease (bone scan and prostate specific antigen [P SA]) and eventually casodex was withdrawn on further progression of di sease (PSA and bone scan). Two patients had declines in PSA levels of 42% and 75% sustained for 3 to 6 months, and 1 patient had a stable co ndition for 2 months. These responses were similar to those of withdra wal of flutamide, which were limited to patients who had received comb ination therapy at the onset of treatment. Thus, the observations in t his report would suggest that the initial and sustained exposure to an antiandrogen is the more important factor in the withdrawal phenomeno n rather than the low androgen environment alone that occurs with init ial luteinizing hormone-releasing hormone analogue monotherapy, orchie ctomy or combination luteinizing hormone-releasing hormone analogue an d antiandrogen.