Title: BACKGROUND: Pain management is the primary goal of treatment of patients with bone metastases' Curre
1MRI Guided Focused Ultrasound, A Novel Treatment
for Palliation of bone Metastases in Radiation
Therapy Failure Patients
Raphael Pfeffer1, Tatiana Rabin1, David
Gianfelice2, Alexander Beck3, Yael Inbar1, Boaz
Liberman1, Nogah Shabshin1, Susanna Hengst3,
Chander Gupta2, Arik Hanannel4, Osnat Dogadkin4,
Raphael Catane1 1Sheba Medical Center,
Tel-Hashomer, Israel, 2Toronto General Hospital,
Toronto, ON, Canada, 3Department of Radiology,
Charite Hospital, Berlin, Germany, 4InSightec
LTD, Haifa, Israel.
- BACKGROUND Pain management is the primary
goal of treatment of patients with bone
metastases. Currently existing palliative
treatments such as localized irradiation,
chemotherapy, oral bisphosphonates, strontium 89,
radiofrequency ablation or surgery have either
efficacy problems or significant unwanted side
effects. Magnetic Resonance guided Focused
Ultrasound (MRgFUS) uses focused acoustic energy
to create, non-invasively, a heat-coagulated
lesion deep within the body while treatment
monitoring is done as a closed loop using MR real
time thermal imaging. Thus physician can
correctly localize tumors, deliver acoustic
energy ("sonicate"), monitor energy deposition in
real time and accurately control the deposited
thermal dose. - PURPOSE Evaluate the safety and efficacy of
MRgFUS for the palliation of pain due to bone
metastatic lesions in patients for whom other
available treatments were considered either not
effective or not feasible. - MATERIAL AND METHODS 32 lesions in 31
patients (aged 40-85) were treated by MRgFUS in 3
medical centers Sheba Medical Center
(Tel-Hashomer, Israel), Toronto General Hospital
(Toronto, Ontario, Canada), and Charite Hospital
(Berlin, Germany), using ExAblate2000 system
(InSightec Ltd. Haifa, Israel). A total of 36
treatments were performed, 4 lesions were treated
twice. Patients were followed for a period of at
least 3 months. Effectiveness of pain palliation
was evaluated using Visual Analog Scale (VAS)
pain questionnaires and changes in dosage of
patients medications. - RESULTS An efficacy analysis was conducted
on 25 patients, who received adequate treatment
and reached 3 month follow up. 72 of patients
(18/25) had a significant reduction in pain (gt 2
points on VAS scale, p-valuelt0.003) at the
3-month follow up. Of these 50 (9/18) reported a
VAS score of zero. 24 had no response and 1
patient (4) experienced worsened pain levels.
Average VAS score dropped from 5.9 prior to
treatment to 1.8 three months post treatment. 52
of patients reported substantial pain relief as
early as 3 days post treatment. 67 of patients
with recorded medication data decreased their use
of opioid analgesics. - No severe device related adverse events were
recorded in any of the patients.
Fig 2 Patients position during treatment. Left
schematic display, Right MR Axial T2w planning
image with ultrasound beam overlay (blue)
Fig 1 System overview
Fig 3 Visual Analog Scale (VAS) for pain
evaluation
Fig 4 Average pain score (VAS) graph, showing
significant symptoms improvement
Conclusion MRgFUS produces a controlled,
well-localized ablation of the impaired bone and
soft tissue in close proximity to bone. This can
be achieved without significant damage to the
bone or other tissue in the vicinity. MRgFUS
provides durable palliative benefits while
avoiding side effects of traditional therapy.