Treatment outcomes of stereotactic radiosurgery for primary and metastatic sarcoma of the spine

Abstract

Abstract Purpose This study evaluated the treatment outcomes of spine stereotactic radiosurgery (SRS) in sarcoma patients. Materials and methods A total of 44 sarcoma patients and 75 spinal lesions (6 primary tumors, 69 metastatic tumors) treated with SRS were retrospectively reviewed between 2006 and 2017. The median radiation dose was 33 Gy (range, 18–45 Gy) in 3 fractions (range, 1–5) prescribed to the 75% isodose line. Results The median follow-up duration was 18.2 months. The 1-year local control was 76.4%, and patients treated with multiple vertebral bodies and large planning target volume (PTV) size were identified as unfavorable prognostic factors on multivariate analyses. Progression-free survival at 1 year was 31.9%, with the interval between initial diagnosis and SRS and extent of disease at the time of treatment being significant prognostic factors. The 1-year overall survival was 80.5%, and PTV > 16 cc and visceral metastases were independently associated with inferior overall survival. Conclusion SRS for spinal sarcoma is effective in achieving local control, particularly when treating a single vertebral level or a small treatment volume, resulting in an excellent control rate. The extent of disease at the time of SRS is significantly correlated with survival outcomes and should be considered when treating spine sarcoma.