Single fraction radiosurgery, fractionated radiosurgery, and conventional radiotherapy for spinal oligometastasis (SAFFRON): A systematic review and meta-analysis

Raj Singh, Eric J. Lehrer, Basem Dahshan, Joshua D. Palmer, Arjun Sahgal, Peter C. Gerszten, Nicholas G. Zaorsky, Daniel M. Trifiletti

Research output: Contribution to journalReview article


Background and purpose: To perform a systematic review/meta-analysis of outcomes for patients with spinal metastases treated with stereotactic radiosurgery (SRS) (either single-fraction (SF-SRS) or multiple-fraction (MF-SRS)) or conventional radiotherapy (RT). Materials and methods: Thirty-seven studies were identified. Primary outcomes were 1-year local control (LC) and acute/late grade 3–5 toxicities (including vertebral compression fractures (VCF)). Weighted random effects meta-analyses using the DerSimonian and Laird methods and meta-regressions were conducted to characterize and compare effect sizes. Mixed effects regression models were used in dose analyses. Results: A total of 3237 patients with 4911 lesions were included; 43.8%, 19.7%, and 36.5% of lesions received SF-SRS, MF-SRS, or RT, respectively. SF-SRS resulted in improved 1-year LC (92.9% (95% CI: 86.4–97.4%); p = 0.007) compared to RT (81.0% (95% CI: 69.2–90.5%)) with no difference between MF-SRS (82.1%; p = 0.86) and RT. On subgroup analysis of de novo metastases, superior 1-year LC following SF-SRS (95.5% (95% CI: 87.4–99.6%)) was maintained compared to RT (83.6% (95% CI: 70.4–93.5%); p = 0.007). A 4.7% increase in LC was noted for each 10 Gy10 increase in biologically effective dose (BED10, assuming an alpha/beta = 10) with SRS (p < 0.001). No difference in toxicities were found between SF-SRS (0.4%), MF-SRS (0.2%), or RT (0%). Higher VCF rates were noted following SF-SRS (19.5%) vs. MF-SRS (9.6%; p = 0.039)) with no correlation between dose and VCF rates. Conclusion: SF-SRS resulted in superior LC with a roughly 5% LC benefit for every 10 Gy10 increase in BED10 with higher VCF rates compared to MF-SRS. If LC is the goal of treatment, then SRS may be a preferred treatment modality. However, these results are hypothesis-generating, and prospective randomized clinical trials are indicated to definitively address the question of whether SRS results in improved LC compared to RT.

Original languageEnglish (US)
Pages (from-to)76-89
Number of pages14
JournalRadiotherapy and Oncology
StatePublished - May 2020


All Science Journal Classification (ASJC) codes

  • Hematology
  • Oncology
  • Radiology Nuclear Medicine and imaging

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