title: Intermittent androgen-deprivation therapy in prostate cancer: a critical review focused on phase 3 trials.
abstract: BACKGROUND
  Intermittent androgen deprivation (IAD) in prostate cancer (PCa) patients has been proposed to delay development of castration resistance and to reduce the side effects and costs of androgen deprivation therapy (ADT).
  
  
  OBJECTIVE
  This review analyzes (1) the oncologic and quality of life (QoL) results from randomized phase 3 trials comparing IAD and continuous ADT and (2) the prognostic parameters for IAD.
  
  
  METHODS
  We searched the Medline and Cochrane Library databases (primary fields: prostate neoplasm and intermittent androgen deprivation; secondary fields: randomized trials, survival, quality of life, predictors) without language restriction.
  
  
  RESULTS
  We found seven extensively described phase 3 trials randomizing 4675 patients to IAD versus continuous ADT. Other randomized trials investigating IAD have been performed, but available data are limited and have been published only in preliminary fashion. In all seven trials, patients spent most of their time on, rather than off, ADT. The induction periods ranged from 3 mo to 8 mo; in all but one trial, the PSA level designated for ADT discontinuation was <4 ng/ml. Mean follow-up ranged from 40-108 mo. Collectively, these trials support the concept that, mainly in metastatic cases, IAD can produce oncologic results similar to continuous ADT. In terms of overall survival, the hazard ratios for IAD and continuous ADT were very similar (range: 0.98-1.08). The QoL benefit of IAD appears to be modest at best. With IAD, QoL is likely influenced by the duration of the off-treatment periods and by the rate of testosterone recovery.
  
  
  CONCLUSIONS
  The evidence indicates that IAD is not inferior to continuous ADT. Data are insufficient to determine whether IAD is able to prevent the long-term complications of ADT. More comparative analysis focused on QoL is warranted.
authors.affiliation: Department of Urology, University Sapienza, Rome, Italy. Electronic address: sciarra.md@libero.it.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Sciarra
authors.forename: Per Anders
authors.initials: PA
authors.lastname: Abrahamsson
authors.forename: Maurizio
authors.initials: M
authors.lastname: Brausi
authors.forename: Matthew
authors.initials: M
authors.lastname: Galsky
authors.forename: Nicolas
authors.initials: N
authors.lastname: Mottet
authors.forename: Oliver
authors.initials: O
authors.lastname: Sartor
authors.forename: Teuvo L J
authors.initials: TL
authors.lastname: Tammela
authors.forename: Fernando
authors.initials: F
authors.lastname: Calais da Silva
mesh_terms: D000726:Androgen Antagonists / Q000008:administration & dosage* / Q000009:adverse effects; D018931:Antineoplastic Agents, Hormonal / Q000008:administration & dosage* / Q000009:adverse effects; D017326:Clinical Trials, Phase III as Topic; D004334:Drug Administration Schedule; D019317:Evidence-Based Medicine; D006801:Humans; D008297:Male; D009376:Neoplasms, Hormone-Dependent / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology; D011471:Prostatic Neoplasms / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology; D064129:Prostatic Neoplasms, Castration-Resistant / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology; D011788:Quality of Life; D016032:Randomized Controlled Trials as Topic; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D000726:Androgen Antagonists; D018931:Antineoplastic Agents, Hormonal
keywords: Androgen deprivation; Intermittent therapy; Prostate neoplasm