Single-fraction versus multifraction stereotactic radiosurgery for spinal metastases: systematic review and meta-analysis.

Objective: Stereotactic radiosurgery (SRS) plays an important role in the treatment of spinal metastases by delivering precise, high-dose radiation to the target region while sparing critical structures. Although various dosing and fractionation schemes have been reported, the optimal regimen remains a topic of debate. The aim of this study was to compare single- versus multifraction SRS (≤ 5 fractions) in the treatment of spinal metastases regarding oncological outcome, pain improvement, and complications, with special concern about vertebral compression fracture (VCF).

Methods: A systematic review was conducted using the PubMed, Scopus, and Embase databases in October 2024 in accordance with PRISMA guidelines. The random-effects model was used for statistical analysis and quality appraisal was assessed using the Risk of Bias in Non-Randomized Studies-of Interventions (ROBINS-I) tool.

Results: A total of 26 studies comprising 4125 patients and 5408 lesions were included in this study. Single-fraction treatment demonstrated superior local control (HR 0.58, p = 0.023), particularly at doses exceeding 20 Gy (HR 0.28, p < 0.0001). However, overall survival did not differ significantly between the two groups (HR 0.78, p = 0.761). Pain relief was comparable between the groups (OR 0.94, p = 0.63). Although the VCF rate was higher in the single-fraction group (OR 1.32, p = 0.32), the difference was not statistically significant, even at doses greater than 20 Gy. Additionally, no significant differences were observed in overall complication rates (OR 1.98, p = 0.12).

Conclusions: This study highlights the superiority of high-dose single-fraction regimen in controlling spinal metastatic tumors compared with multifraction lower doses, with comparable overall survival, complication rates, and VCF incidence. However, prospective randomized studies are necessary to better determine the optimal regimen for different patient populations.