Surgical decompression of metastatic epidural compression (MEC) improved ambulatory function. Spine radiosurgery can accurately target the epidural tumor and deliver high radiation doses for tumor control. Therefore, a clinical trial was performed to quantitatively determine the degree of epidural decompression by radiosurgery of metastatic epidural compression.

Sixty-two patients with a total of 85 lesions of metastatic epidural compression were treated. Epidural compression was diagnosed by magnetic resonance imaging (MRI) scans. Main criteria of inclusion were neurological status with muscle power 4 of 5 or better. Radiosurgery was performed to the involved spine segment, including the epidural mass with median dose of 16 Gy (range 12-20 Gy) in a single session. All patients had prospective clinical follow-up, ranging from 1-48 months (median 11.5 months), and 36 patients had pretreatment and post-treatment imaging, ranging from 2-33 months (median 9.3 months). Primary endpoints were epidural tumor control and thecal sac decompression.

The mean epidural tumor volume reduction was 65 +/- 14% at 2 months after radiosurgery. The epidural tumor area at the level of the most severe spinal cord compression was 0.82 +/- 0.08 cm(2) before radiosurgery and 0.41 +/- 0.06 cm(2) after radiosurgery (P < .001). Thecal sac patency improved from 55 +/- 4% to 76 +/- 3% (P < .001). Overall, neurological function improved in 81%.

This study demonstrated a radiosurgical decompression of epidural tumor. Although neurosurgical decompression and radiotherapy is the standard treatment in patients with good performance, radiosurgical decompression can be a viable noninvasive treatment option for malignant epidural compression.