A Phase 2 Clinical Trial of SABR Followed by Immediate Vertebroplasty for Spine Metastases

Abstract

Purpose: To determine the pain response and prevention of vertebral compression fractures (VCFs) after single-fraction stereotactic ablative radiation therapy (SABR) in conjunction with immediate vertebroplasty for spine metastases. Methods and Materials: Patients with localized spine metastases free from VCF associated with loss of vertebral height with a pain score ≥4 using the visual analog scale were enrolled. Spine SABR was performed with 20 Gy delivered to the gross disease and 14 Gy to the contiguous bone marrow in a single fraction. Immediate, prophylactic vertebroplasty was performed within 1 month after spine SABR. The primary endpoint was pain response at 3 months compared to the historical control with external beam radiation therapy from Radiation Therapy Oncology Group study 9714. Secondary endpoints included pain response at 1 month, duration of pain response, vertebroplasty rate, VCF rate, local control, and overall survival. Results: Thirty-five patients were enrolled, of whom 29 were deemed eligible and underwent single-fraction spine SABR. Twenty-three of these patients subsequently underwent prophylactic vertebroplasty. The 3-month pain response was significantly improved compared to Radiation Therapy Oncology Group study 9714: 95% versus 51% (P