Feasibility and Toxicity of Degarelix for Prostate Downsizing Prior to Permanent Seed Prostate Brachytherapy

This study will investigate the efficacy of Degarelix, a Luteinizing Hormone Releasing Hormone (LHRH) antagonist, to reduce prostate volume prior to permanent seed prostate brachytherapy. There are 2 eligible populations of men, all of whom will have selected brachytherapy as their treatment of choice for their prostate cancer. Either they have an enlarged prostate that requires size reduction to render brachytherapy technically feasible, or they require androgen ablation in conjunction with brachytherapy for optimal tumor control. The hypothesis is that Degarelix will provide > 30% volume reduction by 3 months in > 30% of men.

All men will have a baseline transrectal ultrasound for brachytherapy planning that has demonstrated an enlarged prostate with or without pubic arch obstruction. After signing the informed consent document they will have a loading dose of 240 mg Degarelix and then monthly maintenance dose injections of 80 mg until such time as sufficient prostate reduction has occured (2-3 months) or they complete the 6 months of required androgen ablation for their disease status.

• Drug: Degarelix
  240 mg loading dose followed by monthly 80 mg maintenance dose for 2-3 months
• Drug: Degarelix
  240 mg loading dose of Degarelix followed by 80 mg maintenance doses every month for a total duration of 6 months.

• Experimental: Favorable prostate cancer with pubic arch interference
  Men in this arm have chosen brachytherapy for management of localized prostate cancer and do not require androgen ablation for oncologic reasons but have an enlarged prostate causing pubic arch interference and thus require prostate size reduction prior to brachytherapy. They will have 2-3 months of Degarelix with measurement of prostate volume at 8 and 12 weeks.
  Intervention: Drug: Degarelix
• Experimental: Intermediate risk prostate cancer, 6 months Degarelix
  Men in this arm have higher risk prostate cancer (upper tier intermediate risk by NCCN guidelines) and require 6 months of androgen ablation in conjunction with brachytherapy. Prostate size must be > 40 cc at baseline so that prostate size reduction measurements are appropriate. Prostate measurements by transrectal ultrasound with be taken at 12 weeks and 20 weeks.
  Intervention: Drug: Degarelix

Inclusion Criteria:

• Histologic diagnosis of prostate cancer
• Favorable risk disease (cT1 or T2a, Gleason score (GS) 6, and PSA < 10 ng/mL)
• Low-tier intermediate risk disease (cT2c,GS=6,and PSA 10-15 ng/mL, OR GS=7 and PSA < 10 ng/mL)
• Intermediate risk disease AND androgen deprivation therapy recommended by the treating physician for oncologic reasons such as (≥ 50% positive biopsy cores,cT2c,PSA 15-20 ng/mL,GS=7)
• Patient requires baseline planning trans-rectal ultrasound for the purposes of prostate brachytherapy, showing prostate volume > 40 mL and pubic arch interference (not required for those requiring androgen ablation for oncologic reasons)

Exclusion Criteria:

• castrate serum testosterone level
• previous or concurrent pelvic radiotherapy
• unable to give written informed consent
• contraindications to permanent seed prostate brachytherapy or to androgen deprivation therapy
• prior treatment for prostate cancer
• prior trans-urethral resection of the prostate
• previous therapy with a 5-α reductase inhibitor, anti-androgen agent, or LHRH agonist
• previous therapy with degarelix