HDR Brachytherapy vs. LDR Brachytherapy Monotherapy in Localized Prostate Cancer

High-dose rate brachytherapy (HDRB) used as monotherapy is emerging as an alternative to Low-Dose Rate brachytherapy (LDRB) with excellent PSA-progression free survival as high as 90-100% for favorable prostate cancer at a median follow-up of 3-5 years. HDRB has many advantages over LDRB such as prospective dosimetry not impacted by setup errors, organ motion and prostate swelling during treatment delivery. In addition, HDRB causes less acute and late urinary toxicity compared with LDRB. Acute urinary retention can lead to prolonged catheterization, pericatheter urine leakage, urinary tract infection and Trans-Urethral Resection of the Prostate resulting in diminished quality of life (QOL) and increased psychological distress. The goal of the investigators' phase II randomized study is to evaluate the differences in QOL in the urinary domain between patients with favourable intermediate risk or extensive low-risk prostate cancer treated with LDRB and HDRB at 3 months using the Expanded Prostate Cancer Index Composite (EPIC) QOL scores. The 3 months cut-off endpoint has been chosen since HDRB-induced urinary toxicity subsides at 12 weeks compared to 12 months with LDRB. Secondary objectives include: bowel and sexual domain EPIC scores and International Prostate Symptom Score. The absolute PSA nadir and a prostate biopsy at 36 months will be reported to assess local control.