Efficacy and Toxicity of Bicalutamide and Dutasteride vs. Standard Care for Prostate Cytoreduction for Brachytherapy

The purpose of this study is to determine if a combination of neoadjuvant dutasteride and bicalutamide has the same efficacy and less toxicity than standard treatment with an LHRH agonist and bicalutamide for prostate cytoreduction prior to permanent implant brachytherapy.

Permanent implant prostate brachytherapy is recognized as the treatment method for prostate cancer that results in the least amount of sexual side effects including erectile dysfunction (ED). However prostate brachytherapy is often limited to patients with a prostate volume less than 50cc because of dosimetric and technical considerations. To counter this fact patients with a prostate larger than 50cc are offered neoadjuvant hormonal therapy to reduce their prostate volume to a value less than 50cc. The pharmacological method most often employed involves treatment with an LHRH agonist, which also involves multiple adverse effects for patients including ED in the majority of patients. This approach may also involve other disadvantages including a possibility of increased cardiovascular mortality a possible increase in urinary toxicity and a reduction in health-related quality of life in patients treated with neoadjuvant hormonal therapy. Despite theses facts, neoadjuvant hormonal therapy remains essentially the sole method used to reduce prostate volume prior to prostate brachytherapy. One study has evaluated the efficacy of a neoadjuvant regimen without an LHRH agonist, comprised of Dutasteride and Bicalutamide to reduce prostate volume. This treatment could theoretically have fewer effects on sexual function and quality of life and could also possibly reduce urinary toxicity of brachytherapy. Nonetheless, these factors have never been evaluated. The cytoreductive efficacy of Bicalutamide and Dutasteride have never been directly compared to standard treatments. The current study is necessary to determine the effects of a neoadjuvant regimen of Bicalutamide and Dutasteride on prostate volume, sexual function, urinary toxicity and quality of life as compared to standard treatment. If it can be determined that there is an advantage with Bicalutamide and Dutasteride this regimen could become a standard of care for prostate cytoreduction prior to brachytherapy.