Comparison of HDR vs. LDR Brachytherapy as Monotherapy for Intermediate Risk Prostate Cancer

This study will offer men with intermediate risk prostate cancer who are suitable for, and interested in, prostate brachytherapy, the opportunity to be randomized between low dose rate (LDR) brachytherapy using permanent implantation of radioactive seeds (the current standard of care in BC) and high dose rate (HDR) or temporary brachytherapy which is also available as a standard of care in BC but only when used as a boost in addition with external beam radiotherapy. In addition, men will be offered the opportunity for testing the aggressiveness of their cancer using Cell Cycle Progression Gene Profile.

Inclusion Criteria: * Clinical stage T1c-T2b, PSA \< 20, Gleason \< 8 * ECOG 0-1 * Low tier intermediate-risk prostate cancer is defined by; o a single NCCN intermediate risk factor (either Gleason 7(3+4) and PSA \< 10 ng/ml OR Gleason 6 and PSA 10-20 ng/ml) * Extensive favorable-risk disease is defined as: * clinical stage T1c-T2a * PSA \< 10 * Gleason 6 * ≥ 50% of biopsy cores containing cancer * PSA density \> 0.2 ng/cc * Selected intermediate risk patients not defined above * \- T1c/T2a * \- PSA \< 10 * -Gleason 4+3 * -\< 33% of cores involved * -Max tumour length in any core 10 mm * No androgen deprivation therapy (ADT) * Prostate volume by TRUS ≤ 60 cc. * Not eligible for, or accepting of, active surveillance according to NCCN guidelines. * Signed study specific informed consent. Exclusion Criteria: * Prior radical surgery for carcinoma of the prostate, * Prior pelvic radiation * Prior chemotherapy for prostate cancer, * Prior TURP or cryosurgery of the prostate * Claustrophobic or unable to undergo MRI