Safety and Efficacy of Radiofrequency Ablation of Brain: A Potentially Minimally Invasive Treatment for Brain Tumours

Abstract

Introduction: Cerebral metastases are associated with a very poor prognosis. The best survival results are seen after surgical resection. However this involves a relatively invasive procedure and many patients are not suitable for surgical resection. We have evaluated the safety and efficacy of radiofrequency ablation of the brain in a sheep model.

Methods: We produced ablations of 1 - 3 cm diameter in the brain of sheep using the RITA starburst XL probe and RITA 1500 generator. We varied the time of RF application between 1 minute and 5 minutes and observed the animals for between 24 hours and 3 weeks for short-term and long-term effects and measured the intracranial pressure (ICP) in 2 animals following RFA.

Results: A total of 8 ablations were produced in 8 sheep. There was no change in the ICP measurements and there were no neurological complications in the 5 sheep with superficial ablation of up to 2 cm. Three sheep failed to regain consciousness due to large ablations near the brain stem and cerebellum. The sizes of the ablations were confirmed on necropsy and there was no other evidence of damage to the surrounding brain. Satisfactory ablation of brain was achieved at 70 °C and an ablation time as short as 3 minutes produced a 1.5 - 2.0 cm diameter of ablation.

Conclusion: Cerebral RFA is a relatively safe and effective technique capable of producing a predictable ablation with no damage to surrounding brain. The potential of this technique requires further evaluation but likely advantages include the ability to treat multiple tumours and perform repeated treatment with a minimally invasive approach.

Key words

Radiofrequency ablation - sheep model - cerebral metastasis - minimally invasive - safety

References

• 1 Wen P Y, Black P M, Loeffler J S. Treatment of metastatic cancer. In: Cancer: Principles and Practice of Oncology. DeVita VT, Hellman S, Rosenberg SA (editors), 6th edn. Philadelphia: Lippencott Williams and Wilkins 2001: pp 2655-2670
• 2 Menovsky T, Beek J F, Roux F X, Bown S G. Interstitial laser thermotherapy: Developments in the treatment of small deep-seated brain tumors.  Surg Neurol. 1996;  46 568-572
• 3 Ryan T P, Trembly B S, Roberts D W, Strohbehn J W, Coughlin C T, Hoopes P J. Brain hyperthermia: Interstitial microwave antenna arrays techniques - the Dartmouth experience.  Int J Radiation Onc BioI Physics. 1994;  29 1065-1078
• 4 Winter A, Laing J, Paglione R, Sterzer F. Microwave hyperthermia for brain tumors.  Neurosurgery. 1985;  17 387-399
• 5 Alkhani A, Lozano A M. Pallidotomy for Parkinson disease: a review of contemporary literature.  J Neurosurg. 2001;  94 43-49
• 6 King J, Zhao J, Glenn D, Clark W, Clingan P, Morris D L. Percutaneous imaging guided radio frequency in situ ablation (RF A) of 44 pulmonary metastases in 20 patients with colorectal cancer.  ANZ J Surg. 2002;  72 (suppl) A52
• 7 Gananadha S, Morris D L. Radiotrequency ablation of liver malignancies.  Gastrointestinal Oncology. 2002;  4 49-58
• 8 Solbiati L, Livraghi T, Goldberg S N, Meloni F, Dellanoce M, Halpern E F, Gazelle G S. Percutaneous radiofrequency ablation of hepatic metastases from colorectal cancer: long term results in 117 patients.  Radiology. 2001;  221 159-166
• 9 Gananadha S, Monis D L. Saline infusion markedly reduces impedance and improves efficacy of pulmonary radiofrequency ablation.  ANZ J Surg. 2002;  72 (suppl) A14
• 10 Merkle E M, Shonk J R, Zheng L, Duerk J L, Lewin J S. MR imaging-guided radiofrequency thermal ablation in the porcine brain at 0.2 T.  European Radiology. 2001;  11 884-892