We investigated the safety and palliative effect of magnetic resonance-guided focused ultrasound surgery (MRgFUS) for pain associated with bone metastases.
Patients and Methods : Eight patients (mean age, 62.3 years), who met the eligibility criteria for this clinical study approved by our Institutional Ethics Committee based on the cooperative protocol, were treated with MRgFUS. The main inclusion criterion was localized painful metastatic lesions of the bone in patients for whom other pain palliation treatments had proved ineffective. The targeted sites included the sacrum (n=2), ilium (n=2), scapula (n=2), and femur (n=2), and the mean follow-up period was 6 months. All the procedures were performed as a single-session treatment using the ExAblate 2000TM (InSightec Ltd.) treatment system, which is integrated into the patient table of the MRI scanner. The study endpoints were a change in the intensity of the worst pain due to bone metastases as a result of the treatment, as measured on a numerical rating scale (NRS) ; interference of pain with daily activities, as determined by the Brief Pain Inventory (BPI-interference) ; a change in the imaging appearance; and safety.
Results : Pain relief was obtained in all patients early after treatment, with a reduction in the median NRS score from 7.0 (range : 4-8) at the baseline to 1.0 (range : 0-3) at the end of follow-up, as well as in the BPI-interference scores. The mean time required for a single-session treatment was 86.8 min (range : 40-126 min), with a mean number of sonications of 17.0 (range : 10-27) and a mean energy applied of 771.5J (range : 306.5-1240.7J). No significant growth of tumors was observed, nor were there any treatment-related adverse events.
Conclusions : These results suggest that MRgFUS has a non-invasive palliative effect on localized pain in patients with bone metastasis.
