title: Intermittent androgen castration: a biological reality during intermittent treatment in metastatic prostate cancer?
abstract: BACKGROUND
  To assess the effects of intermittent maximal androgen blockade (IMAB) on testosterone (T) levels during on- and off-treatment periods.
  
  
  METHODS
  A total of 51 patients with metastatic prostate cancer underwent a 6-months period of continuous maximal androgen blockade (MAB) consisting of leuprorelin (3.75 mg at monthly intervals) plus flutamide (250 mg t.i.d.) followed by IMAB. During each cycle, the cut-off prostate-specific antigen (PSA) levels to stop and resume treatment were 4 and 10 ng/ml, respectively. IMAB continued until progression under treatment occurred. Monthly PSA and T measurements were performed in central laboratories.
  
  
  RESULTS
  From the 51 patients included (mean age 67.6 years), 27, 16, 12, 8 and 5 underwent a second, third, fourth, fifth and sixth cycle, respectively (mean follow up: 17 months). Before treatment, 4 patients had a T lower than normal laboratory value but these recovered all to a normal T value at the end of the first cycle. During the 6 cycles, only 8 patients did not recover a normal T at least once during the off-treatment periods (OTP). The mean T values at the end of each OTP did not change during these 6 cycles (Anova test, p=0.621) with a mean stable recovery delay of 32-43 days (Anova test, p=0.722).
  
  
  CONCLUSIONS
  IMAB protocol with an initial 6-month treatment period can result in an intermittent castration with the recovery of normal T levels in most patients during six consecutive cycles of treatment.
authors.affiliation: Urology Department, Clinique Mutualiste, Saint Etienne, France. nmottet@mutualite-loire.com
authors.forename: N
authors.initials: N
authors.lastname: Mottet
authors.forename: C
authors.initials: C
authors.lastname: Lucas
authors.forename: E
authors.initials: E
authors.lastname: Sene
authors.forename: C
authors.initials: C
authors.lastname: Avances
authors.forename: L
authors.initials: L
authors.lastname: Maubach
authors.forename: J M
authors.initials: JM
authors.lastname: Wolff
mesh_terms: D000368:Aged; D000726:Androgen Antagonists / Q000008:administration & dosage / Q000627:therapeutic use*; D018931:Antineoplastic Agents, Hormonal / Q000008:administration & dosage / Q000627:therapeutic use; D014408:Biomarkers, Tumor / Q000097:blood; D004334:Drug Administration Schedule; D005485:Flutamide / Q000008:administration & dosage / Q000627:therapeutic use*; D005500:Follow-Up Studies; D006801:Humans; D016729:Leuprolide / Q000008:administration & dosage / Q000627:therapeutic use*; D008297:Male; D009362:Neoplasm Metastasis; D011446:Prospective Studies; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood / Q000188:drug therapy* / Q000556:secondary; D013739:Testosterone / Q000097:blood*; D016896:Treatment Outcome
chemical_list: D000726:Androgen Antagonists; D018931:Antineoplastic Agents, Hormonal; D014408:Biomarkers, Tumor; D013739:Testosterone; D005485:Flutamide; D017430:Prostate-Specific Antigen; D016729:Leuprolide