Spine SBRT is considered a standard of care for the treatment of spinal metastases. Compared to conventional radiation therapy, spine SBRT delivers high doses of radiation to the affected areas to the spinal metastases.

This study is interested in seeing whether an additional 'boost' of radiation, delivered to the affected area in the spine, will result in better long-term control of the tumor; help reduce pain; and reduce long-term side effects of radiation therapy.

Inclusion Criteria:

• Histopathologically confirmed solid tumor malignancy, or strong suspicion based on clinical and radiographic examination of malignancy
• Spinal metastases with paraspinal disease extension documented with MRI and recommended for treatment with SBRT
• Post-operative SBRT is permitted (after stabilization and/or decompression surgery) as long as no prior radiotherapy had been delivered to the spinal level planned for trial treatment and paraspinal disease is present
• ECOG performance status 0-2
• Able to tolerate protocol SBRT
• Age 18 years or older
• Patient is able and willing to complete the Patient Diary (pain and analgesic use)
• Consent must be appropriately obtained in accordance with local requirements. Each patient must sign a consent form prior to enrollment in the trial to document their willingness to participate
• Patients must be accessible for treatment and follow-up
• Treatment to begin within 14 days (ideally 7 days) of radiotherapy simulation

Exclusion Criteria:

• Extremely radiosensitive histology (seminoma, small cell lung cancer, hematologic primaries)
• Prior radiotherapy in the spine target of interest
• Spinal instability as assessed by the Spinal Instability Neoplastic Score with a score of > 12
• Symptomatic cord compression or cauda equine syndrome resulting from bony compression or epidural compression of the spinal cord and cauda equina, respectively. Symptomatic refers to neurologic deficit in the form of motor, bowel or bladder dysfunction
• Pacemaker, such that MRI cannot be performed or treatment cannot be delivered safely
• Cytotoxic chemotherapy within 1 week prior to radiotherapy delivery