Trial Information

Phase II Study of Bicalutamide and Dutasteride for Prostate Cytoreduction Prior to Permanent Implant I-125 Prostate 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.