Phase II High Dose Brachytherapy and Low Dose Rate Brachytherapy as Monotherapy in Localized Prostate Cancer

Inclusion Criteria: * Histologically confirmed adenocarcinoma of the prostate diagnosed within the last 9 months. Patients on active surveillance with evidence of disease progression are eligible to the protocol as long as they meet the eligibility criteria and have a recent prostate biopsy (within 9 months). * Patients with localized prostate cancer are eligible according to the following guidelines: • TNM classification: * Clinical stage T1-T2 and Gleason 6 and PSA \<20 ng/mL * Clinical stage T1-T2 and Gleason 7 (3+4) and PSA \< 15 ng/mL and ≤ 50% of positive nontargeted cores in patients who undergo systematic biopsy * Eastern Cooperative Oncology Group status 0-1. * Bone scan and pelvic CT scan/MRI within the last 6 months at the discretion of the treating physician. * Patient must be ≥ 18 years of age. * Judged to be medically fit for brachytherapy. * Prostate volume by Trans-rectal Ultrasound (TRUS) or Magnetic Resonance Imaging (MRI) ≤ 60 cc within the last 6 months. * American Urological Association (AUA) score ≤ 20 (alpha blockers allowed) within the last 4 weeks. * Patient is able (i.e. sufficiently fluent) and willing to complete the quality of life questionnaires in either English or French. * Patient consent must be appropriately obtained in accordance with applicable local and regulatory requirements. Each patient must sign a consent form prior to enrolment in the trial to document their willingness to participate. * Patients must be accessible for treat…