Evaluation of treatment results of stereotactic body radiotherapy for spinal metastases: A single center experience

Abstract

Aim: To assess oncological outcomes and adverse events of patients receiving single or multi-fraction stereotactic body radiotherapy (SBRT) for spine metastases. 
 Material and Method: Patients with any pathologically proven solid tumor histology who had SBRT to the spine for recurrent or metastatic disease between the years 2010 and 2021 at our department were identified from institutional database. Patient, tumor and treatment characteristics, and follow-up medical records were retrospectively reviewed. Local control (LC) and overall survival (OS) rates were calculated, and adverse events were evaluated.
 Results: A total of 47 patients were treated to 50 spine metastases. Median age was 53 years for all patients. Histologies included breast cancer (45%), non-small cell lung cancer (NSCLC; 21%), prostate cancer (15%) and other types (19%). Median follow-up was 16 months for all patients. Of 47 patients, six (13%) developed local failure and 15 (32%) died without local failure. One and two-year actuarial LC rates were 90.1% and 83.6%, respectively. One and two-year OS rates were 75.1% and 62.7%, respectively. Twenty-two (47%) patients had pain before SBRT. Fifteen (68%) of them had complete or partial pain response at 3 months after SBRT. Vertebral compression fracture, which was grade 1 in severity according to the Common Terminology Criteria for Adverse Events (CTCAE [v.4.03]), was observed in only one (2%) patient and it occurred 46 months after SBRT. No cases of treatment-related radiation myelopathy or any≥grade 3 RT induced acute or late toxicities occurred. 
 Conclusion: This study supports that SBRT to the spine results in high LC without any significant toxicity. The results of ongoing phase 3 trials will highlight whether this high LC benefit reflects to survival in oligometastatic disease.