Stereotactic body radiotherapy for spinal metastases: a review

To evaluate the efficacy and safety of stereotactic body radiotherapy (SBRT) in treating spinal metastases. Two reviewers performed independent literature searches of the PubMed database, searching literatures of the efficacy and safety of SBRT in metastatic spinal diseases. A total of 67 studies were included in the review. Regarding SBRT for de novo spinal metastases, the 1- and 2-year local control (LC) rates were 51-100% and 56-96%, respectively. The local failure rate was 10.5-47.5%, with most studies reporting a local failure rate of < 30%. The 1- and 2-year overall survival (OS) rates were 25.7-80% and 25-60.7%, respectively. The pain relief rate was 41.6-100%. In the postoperative scenario, the LC rate was 70-100%, and the local failure rate was 11.7-33%. Regarding the reirradiated setting, the 1-year LC rate was 71-83%, the local failure rate was 6.0-25.5%, and the 1-year OS rate was 28-68%. The pain relief rate was approximately 35.7-77%. Between studies on single- and multi-fraction SBRT, the 1- and 2-year LC rates with single-fraction SBRT were 71-95% and 70-96%, respectively; the 1- and 2-year OS rates with single-fraction SBRT were 43.5-46% and 43.5-49%, respectively. For the management of spinal metastases, it appears that regardless of the clinical scenario in which SBRT is applied, a high rate of LC is achieved, particularly with single-fraction SBRT, regardless of histology. Additionally, spinal SBRT can establish durable pain palliation with acceptable toxicities.