MR-Guided Ablation of Prostate Cancer Recurrences: Laser and Cryoablation. David A. Woodrum, Lance A. Mynderse, Akira Kawashima, Krysztof R. Gorny, Thomas D. Atwell, Ernest F. McPhail, Bradley Bolster, Kimberly K. Amrami, Haraldur Bjarnason, Matthew R. Callstrom Mayo Clinic, Rochester, MN

Background American Cancer Society estimate: ~190,000 new cases of prostate cancer were diagnosed in Traditional therapies include surgery, radiotherapy, or hormone therapy. Prostate cancer recurrence after definitive therapy can be as high as 30%. Local recurrences are associated with significant risk of disease progression.

Surgery

Local Ablative therapies offer the potential for treatment especially for patients who have been through surgery and radiation therapy with recurrence of cancer and limited treatment options. Background

Why MRI: Lesion Conspicuity Better Lesion Conspicuity Multiplanar imaging Better Lesion Visualization Translates into More Precise Ablation and Better Treatment Outcomes

Two MRI Compatible Systems Used Ablates = Laser Heat Visualase Laser Ablation System 980nm Laser Fiber Heats the tissue cooking the tumor Ablates = Freezing Galil Cryoablation System Uses Argon gas through a small needle Creates an iceball around the tumor

MRI Guided Laser Ablation Visualase Laser Ablation System

Image of the laser diffusing fiber (LDF) within the cooling catheter system (CCS) with the low power localizing laser turned on

Dynamic Contrast Enhancement Laser Ablation Procedure 1.Localize Tumor 2.Place applicators 3.Apply Laser Heat 4.Evaluate Ablation Precontrast MRI Localizing Tumor Live MRI Temperature Imaging Calculated Ablation Zone Post-Ablation Contrast Imaging

MRI Guided Cryoablation Galil Cryoablation System

Joule Thompson Effect +70°C -183°C Orifice Heat Exchanger Helium Argon

Cryoablation Procedure 1.Localize Tumor 2.Place probes 3.Freeze x2 4.Evaluate Ablation Contrast Enhanced MRI Probe Placement From a Suprapubic Approach Iceball Size after 11 minutes of Freezing Post-Ablation Contrast Enhanced MRI

Conclusions MR guided laser ablation and cryoablation of prostate bed recurrences are possible and demonstrate no adverse events in the initial patients. MR guided interventions offer the potential for more precise guidance, monitoring, and ablation in patients with prostate cancer recurrences.