Long-Term Results of a Propensity Score Analysis Comparing 5 × 5 Gy and 10 × 3 Gy of Radiotherapy Alone for Malignant Spinal Cord Compression.

Background/Objectives: For many patients with malignant spinal cord compression (MSCC) not suitable for surgery, irradiation alone is the preferred treatment. A dose-fractionation regimen of 10 × 3 Gy is common for this situation. Since most patients suffer from motor deficits and pain, the number of radiotherapy sessions should be as low as possible. A secondary analysis of a phase 2 trial compared 5 × 5 Gy to a historical control group treated with 10 × 3 Gy. After 1:2 matching, 5  ×  5 Gy appeared similarly effective regarding local progression-free survival (LPFS) at 6 months, motor function, walking ability, and overall survival. Methods: This retrospective study investigated whether these findings are consistent in a larger cohort and after longer follow-up. Additional data were gathered for the phase 2 cohort, follow-up in the control group was not limited to 6 months, and the number of patients in the control group increased from 213 to 728. Results: After propensity-score matching, no significant differences were found regarding LPFS after 12 (p = 0.198), 18 (p = 0.139), and 24 (p = 0.117) months, effect on motor function (p = 0.393), walking ability (p = 0.079), 24-month local control (p = 0.655), and 24-month OS (p = 0.403). Conclusions: Given the limitations of this study, 5 × 5 Gy appears preferable to 10 × 3 Gy in selected patients receiving irradiation without upfront surgery. Clinicians should balance initial convenience for the patients and future limitations when re-irradiation in the same part of the spine is required.