Phase II Laser Focal Therapy of Prostate Cancer

Laser-induced interstitial thermal therapy (LITT) is a novel form of controlled, targeted thermal ablation that may offer measurable advantages over other ablative therapies for focal prostate therapy. Because LITT is magnetic resonance (MR) compatible, it enables an imaging advantage over other surgical or ablation techniques that utilize transrectal ultrasound to target and monitor treatment. MR imaging provides excellent soft-tissue contrast and three-dimensional (3D) anatomical imaging in any arbitrary plane, which can help to improve treatment planning and targeting. Additionally, MR-based temperature monitoring allows real-time feedback during MRI-guided thermal therapy as both deposition of light energy and MR signal acquisition can be performed simultaneously without degradation in the MR signal. Also, being in the MR diagnostic environment allows use of post- treatment imaging to verify tissue damage. Because MR images clearly depict the prostate anatomy and the surrounding critical structures, MR imaging has been incorporated into planning for external- beam radiotherapy, brachytherapy, and other treatments of the prostate. In addition to these basic features, Multiparametric prostate MRI (mpMRI) may be used to identify regions of disease in the prostate and better target therapy. In this study, the investigators propose to evaluate the efficacy of a novel, FDA-approved thermal therapy and feedback system (Visualase® Thermal Therapy System) for the treatment of biopsy confirmed and MR-imageable prostate lesions. This system has been used in humans for the treatment of brain, bone (spine), thyroid, and liver cancers. Early feasibility studies for prostate cancer used a transperineal approach; however it is now being evaluated for the primary treatment of prostate cancer using a transrectal approach. This system allows delivery of laser energy while the patient is simultaneously being imaged by an MRI unit. The system's real-time MR thermal imaging (MRTI) provides information on the thermal dose delivered to the target, resulting in a more precise and controlled delivery which has previously not been possible with other ablative therapies. The investigators hypothesize the system can be integrated into a practical and feasible outpatient treatment paradigm for focal treatment of localized prostate cancer and allow patients to avoid the complications associated with radical whole-gland therapy.