MR guided Focused Ultrasound Surgery for the Palliation of Pain Caused by Bone Metastases

MR guided Focused Ultrasound Surgery (MRgFUS) is a non-invasive thermal ablation technique, shown to be clinically effective in the treatment of uterine fibroids and is currently being evaluated as a method of thermal ablation of benign and malignant breast tumors and liver tumors. This technique uses high-energy ultrasound beams that can be directed to penetrate through the skin and various soft tissues, focused at the target and destroy tumors by increasing the temperature at the targeted tissue volume. The boundaries of the treatment area are sharply demarcated (focused) without causing damage to the surrounding organs. The use of sound waves to ablate tumors was first demonstrated in the 1940s, only recent developments have enabled this technology to become more controlled and hence more feasible. The major breakthrough towards its clinical use came with coupling of the thermal ablative process to advanced imaging. The development of magnetic resonance as the foundation to guide and evaluate the end results of FUS treatment, the image guidance of the ultrasound beam, as well as the development of a reliable method for tissue temperature measurement and real-time feedback of the extent of tissue destruction, have pushed this novel technology forwards in the oncological practice (ExAblate2000, Insightec Haifa Israel).

Pain related to bone metastases is intense and is one of the major reasons for the poor quality of life for these patients. Palliation of this kind of pain was the aim of this new technology. The non-invasive use of focused ultrasound energy was meant to achieve localized analgesia by thermal ablation of tissue at the bone – soft tissue interface of bone metastases.

 This technology of real time fully controlled, non-invasive, thermal ablation was used for the palliation of pain caused by bone metastases, in patients for whom other treatments were either not effective or not feasible. More than 30 patients were treated (including the 13 patients reported in the Annals of Oncology (1).                                                                Treatment safety was evaluated by assessing the incidence and severity of device- related complications up to 6-months post-treatment. Effectiveness of pain palliation was evaluated by Visual Analog Scale, pain questionnaires and changes in the patients medication. Very significant reduction in pain score and use of analgesics is reported.  We conclude that MRgFUS may provide a safe and effective non-invasive alternative for the palliation of pain, caused by bone metastases.  

Bibliographic reference:

1.     R. Catane, A. Beck, Y. Inbar, T. Rabin, N. Shabshin, S. Hengst,  R. M. Pfeffer, A. Hanannel, O. Dogadkin, B. Liberman, & D. Kopelman.: "MR guided Focused Ultrasound Surgery (MRgFUS) for the Palliation of Pain in Patients with Bone Metastases- Preliminary Clinical Experience", Annals of Oncology (Accepted for publication)

Doron Kopelman

Sheba Medical Center, Department of Oncology, Tel-Hashomer, Israel; Tel-Aviv University, Tel-Aviv, Israel