Intraoperative Brachytherapy for Spinal Tumors: A Systematic Review of Indications, Techniques, and Outcomes

Background: Spinal tumors can lead to severe pain, neurological issues and spinal instability. Surgery and radiotherapy are often performed, but protecting the spinal cord during tumor management is still difficult. During surgery, intraoperative brachytherapy delivers radiation directly to the tumor or surgical bed. This review outlines the evidence available regarding its use, outcomes and complications in patients with spinal tumors. Methods: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines, we conducted a systematic literature review in PubMed, ClinicalTrials.gov, the Cochrane Library, Scopus, and Google Scholar for studies published between 2000 and 2025. We included studies evaluating intraoperative brachytherapy for primary or metastatic spinal tumors. The outcomes included overall survival, pain control (Visual Analog Scale), local tumor recurrence, and neurological and functional outcomes. Data were synthesized narratively because substantial clinical and methodological heterogeneity was observed among the included studies. The risk of bias was assessed using the ROBINS-I tool. Results: Seven studies involving 301 patients were included. The studies evaluated different approaches, including permanent iodine-125 seed implantation, plaque-based irradiation, phosphorus-32 brachytherapy, 50-kV intraoperative radiotherapy, and kyphoplasty combined with intraoperative radio-therapy. Individual studies reported local control of 75% at 24 months and 72.9% at 3 years; another study reported 97.1%, 95.9%, and 94.2% at 6, 12, and 24 months, respectively. These are study-specific estimates and were not pooled. In one cohort, local control was reported per treated vertebra, whereas survival was reported per patient. All seven studies had a serious overall risk of bias, and the evidence was limited by small samples, non-randomized designs, and differences in interventions and outcome definitions. Conclusions: IOBT may be a local treatment option for selected patients, but the available evidence does not establish its independent benefit or superiority to contemporary postoperative stereotactic body radiotherapy (SBRT).