Current guidelines suggest postoperative spine Stereotactic Body Radiation Therapy (SBRT) should be delivered within 2-4 weeks after surgery. This approach is rife with logistical complications that create delays and barriers for patients accessing care. An alternative approach delivers postoperative spine SBRT soon after surgery, starting within a single hospital stay. This study will investigate the effects of short-term postoperative spine SBRT on wound complications in a safety lead-in, then will transition to a phase 2 trial investigating local tumor control.

PRIMARY OBJECTIVE:

I. To evaluate the local control rate (LC) of treated metastatic sites in patients who undergo surgery for spinal metastasis followed by short interval postoperative spine Stereotactic Body Radiation Therapy (SBRT).

SECONDARY OBJECTIVE:

I. Evaluate the postoperative wound complication rate in participants who undergo surgery for spinal metastasis followed by short-interval postoperative spine SBRT.

II. Determine the radiation toxicity of short-interval postoperative spine SBRT in participants.

III. Determine the progression-free survival (PFS) in participants who undergo surgery for spinal metastasis followed by short-interval postoperative spine SBRT.

IV. Determine the overall survival (OS) in participants who undergo surgery for spinal metastasis followed by short-interval postoperative spine SBRT.

V. Evaluate the quality of life (QoL) of participants who undergo surgery for spinal metastasis followed by short-interval postoperative spine SBRT.

OUTLINE: Participants will received a short interval postoperative SBRT 3-14 days after standard of care surgery for spinal metastases. The SBRT treatment will be delivered up to five sessions in an inpatient or outpatient setting. Participants are follow-up for at month 1, 6, and 12 after SBRT, until removal from study or death, whichever comes first.

Inclusion Criteria:

1. Participants must have a histologically or cytologically confirmed diagnosis of metastatic malignancy or must have preliminary histology or cytology consistent with a diagnosis of metastatic malignancy.

2. Participants must be considered candidates for postoperative SBRT by the treating radiation oncologist.

3. Participants must have undergone, within the past 13 days, or are planned to undergo minimally invasive or open surgery for the management of a spine metastasis.

4. Disease at any spine level is allowed.

5. Prior therapy

   1. There is no limit on the number of prior spine surgeries or prior courses of radiotherapy directed at the spine if prior therapies occurred at different spinal levels outside the anticipated treatment field.
   2. There is no limit on the number of courses or types of radiotherapy for radiation delivered outside the planned treatment field.

6. Cleared by the primary surgical team for postoperative SBRT, including but not limited to hemodynamic, respiratory, and neurologic stability postoperatively, without immediate postoperative complications noted.

7. Age ≥18 years.

8. Eastern Cooperative Oncology Group (ECOG) performance status ≤ 2 (Karnofsky ≥ 70%, see Appendix 1) 1 month prior to presentation for surgery.

9. Estimated survival >3 months or survival considered adequate to undergo spine surgery as assessed by the primary surgical team.

10. Ability to understand and the willingness to sign a written informed consent document.

11. Ability to understand and willingness to comply with treatment schedule, follow-up visits, laboratory testing, and other requirements of the study, including disease assessment by MRI.

12. Individuals with a prior or concurrent malignancy whose natural history or treatment does not have the potential to interfere with the safety or efficacy assessment of the investigational regimen are eligible for this trial.

13. The effects of radiation on the developing human fetus are generally considered detrimental. Because the radiation therapy used in this trial is known to be teratogenic, individuals of reproductive potential must agree to use adequate contraception (e.g., hormonal or barrier methods, abstinence) for the duration of study participation and for at least 120 days after the last administration of radiation therapy. Should a study participant or their partner become pregnant or suspect pregnancy while participating in this study, they should inform their treating physician immediately.

Exclusion Criteria:

An individual who meets any of the following criteria will be excluded from participation in this study:

1. Prior radiation of any type within the anticipated treatment field (prior radiation outside the anticipated field is acceptable as above).
2. Primary malignancy of the spine (examples: chordoma or sarcoma).
3. Persistent high-grade metastatic spinal cord compression following surgery (Bilsky Grade 3 or higher).
4. Involvement of 3 or more contiguous spinal levels.
5. Involvement of more than 2 non-contiguous spinal levels.
6. American Spinal Injury Association Impairment Scale (ASIA) Grade 3 status.
7. Surgery was a biopsy only.
8. Unable to undergo MRI for any reason.
9. Estimated survival <3 months.
10. Active infection requiring systemic therapy.
11. Active wound complication requiring medical intervention.
12. History of radiation-induced myelopathy from prior spine radiation.
13. History of a collagen vascular disorder (examples: lupus, scleroderma).
14. History of psychiatric or substance abuse disorders that would interfere with cooperation with the requirements of the trial.
15. . A woman of childbearing potential (WOCBP) who has a positive urine pregnancy test within 72 hours prior to allocation. If the urine test is positive or cannot be confirmed as negative, a serum pregnancy test will be required.