Focused Ultrasound and External Beam Radiation Therapy for Painful Bone Metastases: A Phase II Clinical Trial

Background: Recent consensus statements and clinical trials have assessed the value of MRI-guided focused ultrasound surgery for pain palliation of bone metastases; however, a comparison with external beam radiation therapy (EBRT) has not been performed.Purpose: To compare safety and effectiveness data of MRI-guided focused ultrasound and EBRT in the treatment of bone metastases.Materials and Methods: Participants with painful bone metastases, excluding skull and vertebral bodies, were enrolled in a prospec-tive open-label nonrandomized phase II study between January 2017 and May 2019 and underwent either MRI-guided focused ultrasound or EBRT. The primary end point was the overall response rate at 1-month following treatment, assessed via the numeric rating scale (NRS) for pain (0-10 scale, with zero meaning "no pain" and 10 meaning "the worst pain imaginable"). Secondary end points were improvements at 12-month follow-up in NRS and quality of life (QoL) measures, including the Brief Pain Inventory (BPI), QoL-Questionnaire Cancer-15 Palliative Care (QLQ-C15-PAL), and QoL-Questionnaire Bone Metastases-22 (QLQ-BM22) and analysis of adverse events. Statistical analyses, including linear regression, chi 2 test, and Student t test followed the per -protocol principle.Results: Among 198 participants, 100 underwent MRI-guided focused ultrasound (mean age, 63 years +/- 13 [SD]; 51 women), and 98 underwent EBRT (mean age, 65 years +/- 14; 52 women). The overall response rates at 1-month follow-up were 91% (91 of 100) and 67% (66 of 98), respectively, in the focused ultrasound and EBRT arms (P < .001), and complete response rates were 43% (43 of 100) and 16% (16 of 98) (P < .001). The mean baseline NRS score was 7.0 +/- 2.1 for focused ultrasound and 6.6 +/- 2.4 for EBRT (P = .16); at 1-month follow-up, they were reduced to 3.2 +/- 0.3 and 5.1 +/- 0.3 (P < .001), respectively. QLQ-C15-PAL for physical function (P = .002), appetite (P < .001), nausea and vomiting (P < .001), dyspnea (P < .001), and QoL (P < .001) scores were lower in the focused ultrasound group. The overall adverse event rates were 15% (15 of 100) after focused ultrasound and 24% (24 of 98) after EBRT.Conclusion: MRI-guided focused ultrasound surgery and external beam radiation therapy showed similar improvements in pain palliation and quality of life, with low adverse event rates.(c) RSNA, 2023 Supplemental material is available for this article.