Stereotactic Body Radiotherapy in the Treatment of Spinal Metastases

Patients with metastatic disease including polymetastatic, oligometastatic, and oligorecurrent spinal lesions have extended life expectancy secondary to improvements in systemic agents, and thus require durable local control of spine metastases. Stereotactic body radiotherapy (SBRT), which uses highly conformal treatment planning techniques coupled with image-guided technology, has enabled the safe delivery of tumor-ablative doses of radiotherapy. The NOMS decision framework has been developed as a tool to aid in the determination of the optimal treatment of spinal metastases, incorporating radiosurgery, separation surgery, stabilization techniques, and conventional radiation. Tumor radiosensitivity is critical in determining appropriateness of radiosurgery. In general, higher radiation doses provide significant, more durable tumor control, whether single-fraction or hypofractionated regimens are used. Spine SBRT can provide a high likelihood of durable tumor control with very low rates of serious toxicity, and careful attention should be given to dose constraints of organs at risk. Here, we review the indications for spine SBRT via the NOMS decision framework and provide practical information to the radiation oncologist regarding spine radiosurgery.