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Safety of irreversible electroporation treatment for metastatic disease in humans. Silk Mikhail ; Wimmer, Thomas; Getrajdman, George; Durack, Jeremy; Sofocleous, Constantinos T.; Solomon, Stephen B. Interventional Radiology & Image Guided Therapies
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Safety of irreversible electroporation treatment for metastatic disease in humans Silk Mikhail; Wimmer, Thomas; Getrajdman, George; Durack, Jeremy; Sofocleous, Constantinos T.; Solomon, Stephen B. Interventional Radiology & Image Guided Therapies Memorial Sloan Kettering Cancer Center. New York, NY Email:sofoclec@mskcc.org
Agenda • Background on Ablation Devices • Physics (RFA, MWA, IRE) • Pre-Clinical Data • Clinical Applications
Thermal ablation uses Electromagnetic Spectrum MWA 300GHZ 300 MHz R F A 3HZ Thermal ablation uses the EM frequencies of 3 Hz and 300 GHz.
Irreversible Electroporation • Electroporation • Electric pulses create tiny holes in the cell • Temporary as long as the energy is low • 360 V/cm • Chemotherapy and Genetic therapy delivery • “Irreversible” • Higher energy • 680 V/cm1 • Create permanent holes in the cell • Cell loses essential molecules and internal signals tell the cell to die
Electroporation • Reversible electroporation is used to allow genes and drugs to enter cells (300-600 V/cm) • Direct current pulse leads to elevation of transmembrane potentials creating permanent cell membrane pores: ~1,500 V/cm • Strong electric fields applied across a cell can cause: • Irreversible permeabilization • of the cell membrane: “IRE”
Advantages of IRE • IRE is non-thermal • Little to no scar tissue formation • Structural Protein Sparing • Nerves and bile ducts in the area of ablation have the potential to heal after treatment • No heat sink effect • Compared to thermal techniques where blood flow dissipates heat. Electric pulses are not effected by blow flow.
Multiple IRE electrodes to treat larger lesions minimum: 2 parallel electrodes spaced 1.5-2 cm
Case close to bile duct and major vein • Post-Tx • 3 mo. f/u MRI Pre-Tx Tx
Perivascular/periductal Liver Metastases28 patients/ 65 tumors: 1 arrhythmia; 1 PV thrombosis (3%) 6 months: 92% Complete Ablation Kingham P et al: IRE for Perivascular Hepatic Malignant Tumors. J Am Coll Surg 2012; 215(3): 379-87
Animal Lung IRE LUNG close to bronchus Post IRE: GGO Applicators 1 week 3 weeks
Tumor near airway • Post-Tx • 3 mo. PET scan • Pre-Tx • Tx
IRE as an Ablation Tool: Potential Advantages • Non-Thermal: -Application in Locations non eligible for Thermal Ablation -Limit recurrences near vessels by avoiding the “heat sink” effect • Cellular Kill Mechanism Avoids Damage to: - Extracellular Matrix. This may result in fewer complications: Near Bile Ducts, Intestines, Ureters, Bronchi, Vital structures.
IRE Rectal Wall Transmural Necrosis; No Perforation at 14 days
Applications: IRE Where Thermal ablation is NOT feasible • Pancreas: Locally advanced adenocarcinoma 100% success at 90 days.Martin RC e al J Am Coll Surg 2012; 215(3): 361-9 • Perivascular Liver Tumors. Kingham P et al: IRE for Perivascular Hepatic Malignant Tumors. J Am Coll Surg 2012; 215(3): 379-87 • Prostate: A potential Therapeutic Paradigm Shift. Ward JF Curr Opin Urol 2012; (2): 104-108 • Intracranial: Canine brain Surgery. Garcia PA Conf Proc IEEE Eng Med Biol Soc 2009: 6513-6. and Technol Cancer Res Treat 2011; 10(1): 73-83 • Blood Brain barrier Disruption: Rat Hjoui M et al. MRI study on reversible and irreversible electroporation induced blood brain barrier disruption. Plos One. 2012;7(8) • Small Intenstine: Rat: Complete ablation but recovery of Epithelium in 3 weeks. Phillips MA. Br J Cancer 2012; 31; 106(3): 490-5
Enhancing Irreversible Electroporation A zone of Reversible electroporation Surrounds the Area of IRE A lethal agent can be targeted to the reversible zone: Electrochemotherapy Gene Electrotransfer Electrochemotherapy : A new technological approach in treatment of Liver Metastases. Edhemovic et al Technol Cancer Res Treat 2011 Oct; 10(5):475-85 Treatment Planning of Electroporation-Based medical Interventions: electrochemotherapy, gene electrotransfer and IRE Phys Med Biol 2012; 7;57(17)5425-40 Reversible Irreversible Model assumes 360 V/cm threshold for reversible and 680 V/cm threshold for irreversible
Conclusion • Unlike Thermal Ablation, IRE, can be performed in close proximity to bile ducts, major vessels, bladder, rectum, and nerves, with an acceptable safety profile. • Longer term follow up is performed to determine efficacy. • Further research will determine the potential of this new ablation technology