Risk Adapted Spinal Cord/Cauda Constraint Relaxation for High-risk Patients With Metastatic Epidural Spinal Cord Compression Undergoing Spine Stereotactic Radiosurgery

Inclusion Criteria:

1. Greater than or equal to 18 years old
2. Radiographically documented spinal metastasis on spine MRI within 4 weeks of registration
3. Proximity of spinal metastasis to spinal cord or cauda equina which precludes achieving a GTV Dmin of at least 14 Gy per the PI
4. All participants must be able to receive single fraction SSRS at the site of interest with 0.01 cc of the spinal cord receiving 14-16 Gy and/or 0.01 cc of the cauda equina receiving 18-20 Gy. The goal of treatment is to select the minimal dose to the organ at risk which will achieve a GTV Dmin of 14 Gy at the treating physician's discretion.
5. Maximum of 3 contiguous vertebral levels involved with metastasis in the spine to be irradiated in a single session
6. All participants must be able to receive a single fraction spine radiosurgery at the designated site of interest to at least a dose of 18 Gy
7. All participants must have a vertebral level site of interest from C1 to S2
8. Signed informed consent
9. Diagnosis of cancer excluding ultra-radiosensitive histologies (see 4.2)
10. Motor strength ≥ 4 out of 5 in extremity or extremities affected by the level of cord compression
11. ECOG ≤ 2

Exclusion Criteria:

1. Participants with ultra-radiosensitive histologies (lymphoma, multiple myeloma/plasmacytoma)
2. Prior history of radiation at the spinal site of interest
3. Inability to lie supine comfortably for ≥ 60 minutes
4. Progressive neurological deficits due to compression
5. Inability of obtain an MRI
6. Inability or refusal to undergo an MR simulation
7. No eligible for single fraction SSRS for any reason
8. Participants who are pregnant