Increased Dose in Spine Stereotactic Radiosurgery for Metastatic Disease: Are We Underestimating the Risks?

Background and Objectives: The recently published Spine Stereotactic Radiosurgery (SSRS) ESTRO guidelines advise against treating spinal metastatic disease with a single dose equal to or smaller than 18 Gy, prioritizing local control over the potential for complications. This study aims to assess the necessity and validity of these higher dose recommendations by evaluating the outcomes and experiences with lower radiation doses. Materials and Methods: A retrospective evaluation of SSRS patients treated at a single institute was conducted. The outcomes and complications of this cohort were compared to the current literature and the data supporting the new ESTRO guidelines. Results: A total of 149 treatment sessions involving 242 spinal levels were evaluated. The overall local control rate was 91.2%. The mean radiation dose for the local control group compared to the local failure group was similar (17.5 vs. 17.6 Gy, not significant). The overall complication rate was 6%. These results are consistent with previous publications evaluating SSRS for metastatic spinal disease. Conclusions: SSRS dose escalation may increase local control efficacy but comes with a higher risk of complications. The evidence supporting the strong recommendations in the recent ESTRO guidelines is not robust enough to justify a universal application. Given the palliative nature of treatment for metastatic patients, dose determination should be individualized based on patient conditions and preferences, with a detailed discussion about the risk-benefit ratio of increased doses and the level of evidence supporting these recommendations.