Stereotactic radiosurgery (SRS) for primary intradural spinal tumors: A systematic review and meta-analysis.

While primary intradural spinal tumors (PIST) are commonly treated by surgery, the use of stereotactic radiosurgery (SRS) is typically considered when patients are either poor surgical candidates or have recurrent or unresectable tumors. However, the optimal use of SRS in the treatment of PISTs and its efficacy remains relatively unclear. Our aim with this study was to investigate the therapeutic response among PISTs treated with SRS. We performed a systematic literature search in five databases: Medline, Embase (Ovid), Scopus, Web of Science Advance and Cochrane Central from inception to July 8th 2024. We included studies that reported on outcomes among PISTs treated with SRS and meta-analyzed the proportions of recurrence and local control (LC) among them. The quality of included studies was assessed using the MINORS tool for non-randomized studies. We identified 14 studies and classified them by follow-up duration. 4 studies had mean or median follow-up times of less than 3 years (short-term follow-up) and 10 studies had greater than 3 years follow-up (long-term follow-up). The mean and median follow up times ranged from 33 to 54.3 months, and 18 to 60 months, respectively. The overall pooled proportion of short-term LC was 0.98 [95% CI: 0.90-1.00], while long-term LC was 0.94 [95% CI: 0.89; 0.97]. The overall pooled proportion of recurrence was 0.01 [95% CI: 0.00; 0.05] for short-term follow-up and 0.05 [95% CI: 0.03; 0.09] for long-term. Subgroup analyses included long-term LC for hemangioblastomas, meningiomas, schwannomas, and neurofibromas, as well as short-term recurrence for meningiomas and schwannomas. Among subgroups, meningiomas showed the best long-term LC and short-term recurrence, with pooled proportions of 0.99 [95% CI: 0.37; 1.00] and 0.02 [95% CI: 0.00; 0.14], respectively. Our results suggest that treating PISTs with SRS achieves favorable outcomes in terms of LC and recurrence. Meningiomas appear to have the best treatment response in terms of LC, which may be a result of their tumor characteristics. However, our findings should be interpreted with caution, as heterogeneity in how studies defined LC may introduce bias into the pooled estimates.