Low incidence of late failure and toxicity after spine stereotactic radiosurgery: Secondary analysis of phase I/II trials with long-term follow-up.

•5-year local control by site was 91%, with late failures occurring in 3% of sites.•Overall and Grade ≥3 late toxicities were observed in only 5% and 2% of all sites.•Neurologic events occur much earlier than fractures, with last noted at 2.1 years.•No toxicities occurred after 4.1 years through end of follow-up (median 6.7 years)•These data support the high therapeutic ratio of SSRS with long-term follow-up.