KEY POINTS
- This single-centre retrospective cohort included 497 patients with 532 spinal metastases treated between 2013 and 2024 with separation surgery followed by SBRT in five or fewer fractions. Prior overlapping radiotherapy had been delivered in 20% of cases; the most common schedules were 27 Gy in 3 fractions and 30 Gy in 3 fractions.
- The cumulative incidence of local failure was 7.7% at 1 year, 10% at 2 years, and 13% at 3 years. Median overall survival was 14 months.
- Higher CTV Dmin BED10 was the only variable independently associated with local failure: HR 0.96 per Gy (95% CI 0.93–0.99; p=0.005). Two-year local failure was 6.5% above versus 13% below the median CTV Dmin BED10 of 32.75 Gy.
- After excluding previously irradiated lesions, postoperative ESCC ≤1C was associated with approximately twice the odds of achieving the median CTV Dmin BED10 compared with ESCC 2 (OR 2.06; p=0.002). Further decompression to ESCC ≤1B provided no additional dose-deliverability benefit.
- At 2 years, cumulative incidences were 2% for vertebral compression fracture, 1% for radiation myelitis, and 3.8% for hardware failure requiring surgery. Neurological improvement occurred in 56 of 69 patients with preoperative myelopathy.
CLINICAL TAKEAWAY
For patients selected for separation surgery followed by spine SBRT, postoperative ESCC ≤1C may represent a pragmatic surgical target because it facilitates delivery of an adequate minimum CTV dose without evidence of additional dosimetric benefit from more extensive decompression. However, CTV minimum dose—not ESCC grade itself—was associated with local control, and the retrospective single-centre design, heterogeneous fractionation, and potential unmeasured confounding prevent definitive practice-changing conclusions.
SOURCE
International Journal of Radiation Oncology, Biology, Physics