Pain Palliation in Patients with Bone Metastases Using Magnetic Resonance-Guided Focused Ultrasound with Conformal Bone System: A Preliminary Report

Abstract

PurposeWe evaluated the safety and effectiveness of the Magnetic Resonance-guided Focused Ultrasound (MRgFUS) with the ExAblate Conformal Bone System for the palliation of painful bone metastases.Materials and MethodsOur Institutional Review Board approved this study, and all patients gave informed consent prior to enrollment. A total of six painful metastatic bone lesions in five patients were treated using MRgFUS with the ExAblate Conformal Bone System for pain palliation. The follow-up sessions were at 3 days, 2 weeks, 1, 2, and 3 months, and 1 year after treatment. Efficacy was evaluated by the changes in visual analog scale (VAS) scores. At 3-months and 1-year follow-ups, unenhanced computed tomography and contrast-enhanced MR imaging examinations were performed. All adverse events were assessed to evaluate treatment safety.ResultsAll patients showed significant pain relief within 2 weeks. Two patients experienced complete pain reduction that lasted for 1 year. Two other patients showed pain relief measured as VAS scores of 2 and 4 on their last follow-up. Although the remaining patient had experienced significant pain relief in two lesions, the VAS score re-increased on his last follow-up. The size of the enhancing soft tissue mass in metastatic lesions decreased, and new bone formation was seen on follow-up images. Although adverse events were not serious, non-specific leg pain and second degree skin burn were noted.ConclusionMRgFUS was demonstrated to be effective palliative treatment within 2 weeks in selected patients with painful bone metastases.

Magnetic Resonance–Guided High-Intensity-Focused Ultrasound for Palliation of Painful Skeletal Metastases: A Pilot Study

“…While our study is not novel, our results are consistent with previous studies demonstrating the safety and efficacy of MRgFUS as a treatment for metastatic bone pain. [17][18][19][21][22][23][24] Together, our results and the findings of Huisman et al emphasize the need for further research aimed at optimizing and standardizing volumetric ablation in the palliation of bony metastases.…”

Image-guided ultrasound phased arrays are a disruptive technology for non-invasive therapy

“…However, patient positioning on both systems is not straightforward, particularly as many patients have difficulty lying on their painful bone tumors. For this reason, InSightec has developed a dedicated phased array system for bone metastases, which consists of 1000 elements operating at a frequency of 550 kHz, that can be strapped on the patient on top of the tumor [235]. The system has a focal steering range of approximately 30 degrees, and focuses the beam past the tumor, exploiting the high ultrasound absorption in bone and the large beam diameter in the near-field region to increase the ablated bone surface area.…”

Evaluation of Quality of Life Using EORTC QLQ‐BM22 in Patients with Bone Metastases after Treatment with Magnetic Resonance Guided Focused Ultrasound

“…Although several previous studies report the use of MRgFUS for pain palliation treatment performed on bone metastasis patients, the evaluation methods and the results are inconsistent. MRgFUS therapy improved the patients’ QOL by preventing skeletal complications and providing relief from bone pain. However, previous studies did not include a comprehensive assessment and a systematic, disciplined approach to assess and improve the effectiveness of MRgFUS therapy.…”

“…Nevertheless, the evaluation was reversed during the last 4 months in this study. Researchers have found that high‐intensity focused ultrasound ablation can induce pain relief in patients with osteolytic metastatic bone lesion. The VAS score of patients with osteolytic and osteoblastic lesions from Fig.…”