Repeat Stereotactic Body Radiation Therapy for Spinal Metastases: Long-Term Outcomes and Toxicity

Area of Science:

• Radiation Oncology
• Spinal Oncology
• Metastasis Management

Background:

• Stereotactic body radiation therapy (SBRT) demonstrates efficacy in controlling spinal tumors.
• Optimal management strategies following local failure (LF) after initial SBRT for spinal metastases remain undefined.
• This study investigates outcomes of repeat SBRT for recurrent spinal metastases at the same vertebral level.

Purpose of the Study:

• To evaluate the safety and efficacy of repeat SBRT in patients experiencing local failure after initial SBRT for spinal metastases.
• To identify prognostic factors associated with local control and overall survival after repeat SBRT.
• To assess pain response and the incidence of vertebral compression fractures following repeat SBRT.

Main Methods:

• Analysis of a prospectively maintained single-institution database of patients treated with SBRT.
• Inclusion criteria: patients with spinal metastases undergoing repeat SBRT for same vertebral-level LF after initial SBRT.
• Median repeat SBRT dose: 16 Gy (range: 12-30 Gy) in 1-3 fractions.

Main Results:

• 55 patients with 67 metastases met criteria; 67% had prior conventional external beam radiation therapy (cEBRT).
• 2-year local control rate was 77%; prior cEBRT was associated with superior local control (P=.014).
• Pain improvement/stability observed in 75% at 12 months; 2-year cumulative incidence of vertebral compression fracture was 25%. No radiation neuropathy/myelopathy observed.

Conclusions:

• Repeat SBRT is a safe and effective salvage option for recurrent spinal metastases post-SBRT LF.
• This approach is beneficial even in heavily pretreated patients, including those with prior cEBRT.
• Repeat SBRT contributes to durable local control and pain management in spinal metastases.