9500 Background: Pain due to bone metastases is a common cause of cancer-related morbidity. Magnetic resonance guided focused ultrasound surgery (MRgFUS) is a non-invasive approach to thermal tissue ablation. This multi-center phase III trial assessed efficacy of MRgFUS compared with sham treatment to alleviate pain due to bone metastases. Methods: Subjects with a painful bone metastasis amenable to MRgFUS treatment for whom radiation therapy was ineffective or contraindicated were randomized 3:1 to MRgFUS or sham treatment in a single blind design. Un-blinding of sham subjects who did not experience significant pain relief within 2 weeks was permitted with crossover allowed to salvage MRgFUS treatment. Pain response and impact on quality of life (QOL) were assessed using the numerical rating scale (NRS) and Brief Pain Inventory-Quality of Life (BPI-QOL). Safety was also assessed. Results: 142 randomized subjects were included in an intent-to-treat analysis. 67% (95%CI: 57.5-76.0%) of 107 subjects in the MRgFUS arm experienced clinically significant pain relief, equating with an anchor descriptor of “much improved” or better at 3 months compared to 20% of 35 sham arm subjects (p<0.0001). Median baseline and 3 month NRS scores were 7.0 and 2.0 for the MRgFUS arm vs. 7.0 and 6.0 for the sham arm. A clinically significant improvement at 3 months in BPI-QOL score for MRgFUS but not sham treatment was noted [average change: 2.4 vs. 0.2 respectively, (p<0.0001)]. MRgFUS treatment was well tolerated. Conclusions: MRgFUS, as demonstrated by this phase III trial, results in excellent rates of pain relief and improvement in QOL for patients with oncologic related bone pain who are not candidates for radiation therapy. Given these excellent results coupled with a favorable side effect profile, MRgFUS should be considered a primary choice for this patient population. Clinical trial information: NCT00656305.
Magnetic Resonance–Guided Focused Ultrasound for Patients With Painful Bone Metastases: Phase III Trial Results
