The Feasibility of Spinal Stereotactic Radiosurgery for Spinal Metastasis with Epidural Cord Compression

The purpose of this study was to investigate the effectiveness and safety of spinal stereotactic radiosurgery (SRS) in treating spinal metastasis with epidural spinal cord compression (ESCC).

During 2013-2016, 149 regions of spinal metastasis in 105 patients treated with singlefraction (12-24 Gy) spinal SRS were reviewed. Cord compression of Bilsky grade 2 (with visible cerebrospinal fluid [CSF]) or 3 (no visible CSF) was defined as ESCC. Local progression (LP) and vertebral compression fracture (VCF) rates after SRS were evaluated using multivariate competing-risk regression analysis.

The 1-year cumulative incidences of LP for Bilsky grades 0 (n=80), 1 (n=39), 2 (n=21), and 3 (n=9) were 3.0%, 8.4%, 0%, and 24.9%, respectively. Bilsky grade 2 ESCC did not significantly increase the LP rate (no LP for grade 2). The 1-year cumulative incidences of VCF for Bilsky grades 0, 1, 2, and 3 were 6.6%, 5.2%, 17.1%, and 12.1%, respectively. ESCC may increase VCF risk (subhazard ratio [SHR] for grade 2, 5.368; p=0.035; SHR for grade 3, 2.215; p=0.460). Complete or partial pain response rates after SRS were 79%, 78%, 53%, and 63% for Bilsky grades 0, 1, 2, and 3, respectively (p=0.008). No neurotoxicity of grade ≥ 3 was observed.

Spinal SRS for spinal metastasis with Bilsky grade 2 ESCC did not increase the LP rate, was not associated with severe neurotoxicity, and showed moderate VCF and pain response rates. Bilsky grade 3 had a high LP rate.