Background
Phase II single-arm trial. 65 patients with epidural spinal cord compression (ESCC) from spinal metastases, treated with single-fraction SBRT (16–18 Gy) after surgery or as definitive treatment. Primary aim: demonstrate that high-dose SBRT (radiosurgery) to the spinal cord compression site can achieve neurologic preservation without radiation myelopathy. Ryu S et al, Lancet Oncol 2010.
Interventions and follow up
Arm A: Single-fraction spinal radiosurgery: 16 Gy (with epidural disease) or 18 Gy (no epidural disease) to the affected vertebral segment; spinal cord point maximum ≤10 Gy
Primary endpoint: Neurologic preservation (motor function maintenance), local control
mFollow up: 9.0 month
Primary endpoint: Neurologic preservation (motor function maintenance), local control
mFollow up: 9.0 month
Results
Neurologic preservation at 1 year: 84% (ambulatory patients maintained ambulation)
Local control at 1 year: 88%
Radiation myelopathy: 0% — no cases despite cord constraint
Pain response: 74% partial or complete response
Local control at 1 year: 88%
Radiation myelopathy: 0% — no cases despite cord constraint
Pain response: 74% partial or complete response
Adverse events
Main adverse events: Pain flare 24–48 hours: 23% — treated with corticosteroids. Esophagitis grade ≥2: 6%. No radiation myelopathy at median 9 months. Vertebral compression fracture: 5%. No treatment-related deaths.
Conclusions
Single-fraction spinal radiosurgery achieves excellent neurologic preservation and local control for ESCC with acceptable toxicity and no radiation myelopathy when spinal cord constraints (max ≤10 Gy) are respected. This established SBRT as a viable alternative to surgery for select ESCC patients.
Key Limitations
Key Limitations: Single-arm phase II; no comparison to surgery or conventional RT. Short median follow-up (9 months) — radiation myelopathy risk increases with longer follow-up. ESCC grade was not uniformly severe — more severe cord compression may have higher neurologic failure risk. RE-irradiation cord tolerance is different from de novo treatment.
Clinical Context
Spinal SBRT for ESCC is now a recognized alternative to surgery in patients not suitable for decompressive surgery or with radioresistant histologies. Spinal cord Dmax ≤14 Gy (single fraction) is the standard constraint. RTOG 0631 and multiple series confirm 16–18 Gy single-fraction safety with cord dose constraints. Multidisciplinary spine tumor board decisions are standard.
References