Assessing Induction of Double Strand Breaks With Androgen Receptor Partial Agonist in Patients on Androgen Suppression

This is a prospective, single-center, two-phase study to assess the efficacy of single pulsed-dose flutamide in creating DSBs (double strand breaks) in prostate cancer within patients receiving central androgen suppression and brachytherapy. The initial phase is a 6-patient single-arm run-in phase to test feasibility and rule out futility of the intervention. All patients within the run-in phase will receive 50mg flutamide prior to brachytherapy and prostatic biopsy. If futility is ruled out (>1 patients with DSBs on biopsy), then accrual will continue in the randomized, double-blind phase. Subjects will be randomized in a 2:1 ratio (12:6 patients), for an all-trial total of 18 patients receiving flutamide vs 6 patients receiving placebo.

Inclusion criteria

• Histologically confirmed prostate cancer
• At least one biopsy core with Gleason 7 or higher disease
• The patient has decided to undergo brachytherapy plus androgen suppression as treatment modality for his prostate cancer (with or without supplemental external beam radiation)
• Suitable volume of disease for biopsy:
• clinically palpable disease corresponding to (ipsilateral to) any involved core on biopsy
• Signed study-specific consent form prior to registration

Exclusion criteria

• Known hypersensitivity or allergic response to flutamide
• Severe hepatic impairment
• Major medical or psychiatric illness which, in the investigator's opinion, would prevent completion of treatment and would interfere with follow up.