INCIDENCE AND CHARACTERISTICS OF ANTIANDROGEN WITHDRAWAL SYNDROME IN PROSTATE-CANCER AFTER TREATMENT WITH CHLORMADINONE ACETATES

Objectives: In patients with progressive prostate cancer who have been treated with surgical or medical castration plus an antiandrogen, ant iandrogen withdrawal can result in a significant decline in serum pros tate-specific antigen (PSA). Although the incidence of antiandrogen wi thdrawal syndrome after combination treatment with the nonsteroidal an tiandrogen flutamide has been thoroughly documented, the phenomenon cl early occurs in many other combination therapies and is presently bein g widely investigated. This paper would like to contribute to this eff ort by describing the endocrine withdrawal phenomenon in patients trea ted with combinations of castration plus chlormadinone acetate, ethyny lestradiol or estramustine phosphate. Materials and Methods: Clinical records of 68 prostate cancer patients who had been treated with surgi cal castration plus the administration of chlormadinone acetate, ethyn ylestradiol or estramustine phosphate, and who had shown clinical prog ression associated with a steady increase in serum PSA, were investiga ted. Forty-one cases were evaluable for changes in PSA after discontin uation of the hormonal agents. Results: Of 28 patients who had been tr eated with chlormadinone acetate, 12 (42.9%) revealed 50% or more decl ine in PSA level following withdrawal of the agent. Among these, 5 cas es (17.9%) showed subjective and/or objective improvements. There was no significant difference in histological grade of the tumor at diagno sis, mode of progression, time interval from the start of endocrine th erapy to discontinuation of the hormonal agents, or PSA levels at with drawal of the agents between patients who did develop antiandrogen wit hdrawal syndrome and those who did not. Conclusion: When a steady incr ease in serum PSA is noted in a prostate cancer patient who has been t reated with castration plus a steroidal antiandrogen, discontinuation of the antiandrogen may benefit the patient.