title: Consequences of an Early PSA Response to Enzalutamide Treatment for Japanese Patients with Metastatic Castration-resistant Prostate Cancer.
abstract: Recent studies have shown that an early prostate-specific antigen (PSA) response to androgen receptor (AR)-targeting agents in metastatic castration-resistant prostate cancer (mCRPC) is associated with a better prognosis. We analyzed early PSA response to enzalutamide and oncological outcomes to study their prognostic significance in the Japanese population.
  
  
  
  Fifty-one patients with mCRPC (26 of pre-docetaxel and 25 of post-docetaxel status) were treated with enzalutamide. The PSA progression-free survival (PFS), radiographic PFS (rPFS) and overall survival (OS) were assessed. The association of rPFS and OS in patients with an early PSA response at 4 weeks after commencement of enzalutamide was studied.
  
  
  
  Early PSA responses were significantly associated with a longer rPFS (median of 47.9 vs. 20.1 weeks, p<0.001, in patients exhibiting a 50% PSA response; median of 40.9 vs. 20.1 weeks, p=0.016, in patients exhibiting a 30% PSA response). OS was also significantly associated with an early PSA response (p=0.002 for patients exhibiting a 50% PSA response, p=0.003 for patients exhibiting a 30% PSA response). Multivariate analysis showed that the predictors of a 50% PSA response were an interval to mCRPC and a docetaxel treatment history, while the predictor of a 30% PSA response was a docetaxel treatment history. Furthermore, a 50% PSA response was independently prognostic of rPFS.
  
  
  
  An early PSA response to enzalutamide was significantly associated with a longer rPFS and OS. This information will aid in the management of patients treated with enzalutamide.
authors: Department of Urology, Gunma University Graduate School of Medicine, Gunma, Japan.
authors: Haruo
authors: H
authors: Kato
authors: Department of Urology, Gunma University Graduate School of Medicine, Gunma, Japan.
authors: Yosuke
authors: Y
authors: Furuya
authors: Department of Urology, Gunma University Graduate School of Medicine, Gunma, Japan.
authors: Yoshiyuki
authors: Y
authors: Miyazawa
authors: Department of Urology, Gunma University Graduate School of Medicine, Gunma, Japan.
authors: Takeshi
authors: T
authors: Miyao
authors: Department of Urology, Gunma University Graduate School of Medicine, Gunma, Japan.
authors: Takahiro
authors: T
authors: Syuto
authors: Department of Urology, Gunma University Graduate School of Medicine, Gunma, Japan.
authors: Masashi
authors: M
authors: Nomura
authors: Department of Urology, Gunma University Graduate School of Medicine, Gunma, Japan.
authors: Yoshitaka
authors: Y
authors: Sekine
authors: Department of Urology, Gunma University Graduate School of Medicine, Gunma, Japan.
authors: Hidekazu
authors: H
authors: Koike
authors: Department of Urology, Gunma University Graduate School of Medicine, Gunma, Japan.
authors: Hiroshi
authors: H
authors: Matsui
authors: Department of Urology, Gunma University Graduate School of Medicine, Gunma, Japan.
authors: Yasuhiro
authors: Y
authors: Shibata
authors: Department of Urology, Gunma University Graduate School of Medicine, Gunma, Japan.
authors: Kazuto
authors: K
authors: Ito
authors: Department of Urology, Gunma University Graduate School of Medicine, Gunma, Japan kazu@gunma-u.ac.jp.
authors: Kazuhiro
authors: K
authors: Suzuki
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D001549:Benzamides; D018572:Disease-Free Survival; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009570:Nitriles; D010669:Phenylthiohydantoin / Q000031:analogs & derivatives* / Q000627:therapeutic use; D017430:Prostate-Specific Antigen / Q000097:blood*; D064129:Prostatic Neoplasms, Castration-Resistant / Q000188:drug therapy* / Q000473:pathology
chemical_list: D000970:Antineoplastic Agents; D001549:Benzamides; D009570:Nitriles; D010669:Phenylthiohydantoin; C540278:enzalutamide; D017430:Prostate-Specific Antigen
keywords: Castration-resistant prostate cancer; early PSA response; enzalutamide; overall survival; radiographic progression-free survival