Brachytherapy is a commonly used treatment for prostate cancer. While the outcomes of brachytherapy are very good, approximately 5% of patients with low or favorable intermediate-risk prostate cancer will recur within the prostate. Those with higher risk disease would have an even higher risk of local recurrence. The standard treatment for this is hormonal therapy, which is associated with significant toxicities and is not curative. Leveraging Sunnybrook’s considerable experience in brachytherapy as the largest centre globally, we aim to study the toxicities, quality of life and efficacy of focal salvage HDR prostate brachytherapy in patients who fail within the prostate after previous brachytherapy.