title: Phase II trial of external beam radiation with etanidazole (SR 2508) for the treatment of locally advanced prostate cancer.
abstract: OBJECTIVE
  To evaluate the efficacy and toxicity of the addition of etanidazole (ETA) to external beam radiation.
  
  
  METHODS
  Fifty eight previously untreated patients with locally advanced adenocarcinoma of the prostate were entered on a Phase II trial of etanidazole (ETA) combined with standard external beam radiation therapy. ETA was given concurrently with irradiation. Four patients received less than 25% of the intended dose of ETA and were ineligible for further analysis. The stage of the remaining patients were T2c-11, T3-39, T4-1, bulky local recurrence after prostatectomy-1, and T3, N1-2.
  
  
  RESULTS
  Forty-five of 54 patients (83.3%) achieved a clinical complete response (CCR) in the prostate and seminal vesicles as judged by digital rectal exam (DRE). Responses were rapid with a median time to CCR of 3.4 months, range 0-22.8 months. Local control was maintained in 82% of the patients who achieved a CCR. Fifteen of 32 eligible patients with a normal DRE underwent prostate biopsies from 12-20 months after treatment, seven had negative biopsies (46.6%). Distant metastases occurred in 18 patients (33.3%). Pretreatment prostatic specific antigen (PSA), Gleason score, and stage were not associated with treatment outcome in a univariate analysis.
  
  
  CONCLUSIONS
  While ETA plus radiation was associated with a rapid CCR, the overall treatment outcome of these patients appeared to be similar to published reports of patients receiving RT alone. The rapid response rate may imply biologic activity of the ETA. In future trials, it may be reasonable to focus on patients at lower risk for the subsequent development of distant disease.
authors.affiliation: Joint Center for Radiation Therapy, Harvard Medical School, Boston, MA 02115.
authors.forename: C
authors.initials: C
authors.lastname: Beard
authors.forename: L
authors.initials: L
authors.lastname: Buswell
authors.forename: M A
authors.initials: MA
authors.lastname: Rose
authors.forename: L
authors.initials: L
authors.lastname: Noll
authors.forename: D
authors.initials: D
authors.lastname: Johnson
authors.forename: C N
authors.initials: CN
authors.lastname: Coleman
mesh_terms: D000230:Adenocarcinoma / Q000532:radiotherapy*; D017341:Etanidazole / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000532:radiotherapy*
chemical_list: D017341:Etanidazole; D017430:Prostate-Specific Antigen