title: Antiandrogen withdrawal syndrome with cyproterone acetate.
abstract: OBJECTIVE
  To determine whether the antiandrogen withdrawal syndrome occurs with the steroidal antiandrogen cyproterone acetate.
  
  
  METHODS
  Cyproterone acetate was withheld in 12 patients with progressing androgen-independent metastatic prostate cancer. Eight patients had been receiving cyproterone acetate concomitant with androgen ablation, and in 4 patients it was prescribed after failure of androgen suppression. Time to response and to disease progression were defined by serum prostate-specific antigen (PSA) levels and imaging studies.
  
  
  RESULTS
  PSA levels decreased in 5 of the 1 2 patients; in 4 of them (33%), the decrease exceeded 50%. The decline lasted a median of 24 weeks (range 9 to 37.8). All 5 patients had received initial concomitant exposure to androgen ablation and cyproterone acetate.
  
  
  CONCLUSIONS
  We recommend that the steroidal antiandrogen cyproterone acetate be added to the list of agents capable of inducing antiandrogen withdrawal syndrome.
authors.affiliation: Genitourinary Medical Oncology Unit, Rabin Medical Center, Petah Tikva, Israel.
authors.forename: A
authors.initials: A
authors.lastname: Sella
authors.forename: D
authors.initials: D
authors.lastname: Flex
authors.forename: A
authors.initials: A
authors.lastname: Sulkes
authors.forename: J
authors.initials: J
authors.lastname: Baniel
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000726:Androgen Antagonists / Q000009:adverse effects*; D017373:Cyproterone Acetate / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000097:blood / Q000188:drug therapy*; D013375:Substance Withdrawal Syndrome
chemical_list: D000726:Androgen Antagonists; D017373:Cyproterone Acetate; D017430:Prostate-Specific Antigen