Single- or Two-Fraction Spine Stereotactic Radiosurgery for the Treatment of Vertebral Metastases

Inclusion Criteria

• Karnofsky performance status (KPS) >= 70
• Recursive partitioning analysis (RPA) class 1 (KPS > 70 AND controlled systemic disease) or RPA class 2 (KPS > 70, uncontrolled systemic disease OR KPS =< 70, age >= 54, no visceral metastases)
• Vertebral metastases from C3 to L5 based on bone scan, computed tomography (CT), positron emission tomography (PET), or magnetic resonance imaging (MRI). Patients with lesions at C1-C2 and S1-Coccyx either previously or concurrently treated are permitted, but only C3-L5 lesions may receive protocol treatment
• Vertebral metastases to be treated on study must be (1) solitary, (2) at two contiguous levels, or (3) a maximum of three separate sites, with a maximum of two contiguous levels
• Radioresistant metastases are permitted (including sarcomas, melanomas, and renal cell carcinomas)
• Patients with epidural disease are permitted so long as there is no cord compression
• Paraspinal extension is permitted, so long as the paraspinal component is =< 5 cm
• Multiple small metastatic lesions (< 20% vertebral body involvement) of no clinical correlate are permitted, and not included in the irradiated segments as per Radiation Therapy Oncology Group (RTOG) 0631
• History and physical within 60 days of registration. May be completed virtually
• Negative pregnancy test within 60 days of registration for women of childbearing potential
• Diagnostic spine MRI of interest within 60 days of registration
• Neurological exam within 60 days of registration to rule out rapid neurological decline. Mild to moderate neurological deficits are acceptable, as long as distance between lesion and spinal cord is >= 3 mm
• Patients may have prior external beam radiation therapy (EBRT) at the index site
• Informed consent of the participant

Exclusion Criteria

• SRS of hematologic malignancies including lymphoma and multiple myeloma (patients with concurrent hematologic malignancies and multiple myeloma would otherwise be eligible)
• Primary neoplasms of the spine
• Prior corpectomy, kyphoplasty/vertebroplasty, or instrumentation at the site of planned sSRS
• Spinal cord compression due to metastasis within the area(s) to be treated
• Paraspinal mass of index lesion(s) > 5 cm
• Patients with rapid neurologic decline
• Bony retropulsion of index lesion(s) resulting in neurologic deficit
• Patients with mechanical instability of the spine
• Patients with active connective tissue disease
• Patients who previously underwent sSRS to the vertebrae of interest
• Patients with diffuse or multilevel metastatic spinal disease with > 20% involvement of vertebral bodies, defined as involvement of > 5 vertebral levels
• Inability to participate in study activities due to physical or mental limitations
• Inability or unwillingness to return for all required follow-up visits and imaging
• Inability to deliver sSRS, either 18 Gy in one fraction, or 24 Gy in two fractions