Combined Ablation and Radiation Therapy of Spinal Metastases: A Novel Multimodality Treatment Approach

Background: Radiation therapy (RT) is the current gold standard for palliation of painfulvertebral metastases. However, other percutaneous modalities such as radiofrequency ablation(RFA), cryoablation, and vertebral augmentation have also been shown to be effective in alleviatingsymptoms. Combined RT and ablation may be more effective than either therapy alone in palliatingpainful metastatic disease to the spine.Objective: To evaluate the safety and efficacy of combined ablation, either RFA or cryoablation,and RT in the treatment of spinal metastases.Study Design: Retrospective study.Setting: This is a retrospective study at a single institution.Methods: Medical records of all patients who underwent ablation of spine lesions at a singleinstitution between March 2012 and June 2014 were reviewed; patients treated with both RTand either RFA or cryoablation concurrently were identified. Pain scores before and after RFA weremeasured with the numerical rating scale (NRS) (0 – 10 point scale) and compared. Proceduralcomplications, changes in general activity level, and pain medication usage after ablation were alsorecorded. When available, follow-up imaging was evaluated for evidence of residual or recurrentdisease.Results: Twenty-one patients with 36 spine metastases were treated with RT and percutaneousablation concurrently; either RFA (21/22) or cryoablation (1/22). One patient received 2 separateRFA treatments. Overall, mean worst pain score (8.0, SD = 2.3) significantly decreased at bothone week (4.3, SD = 3.1; P < .02) and 4 weeks (2.9, SD = 3.3; P < .0003). Temporary postprocedural radicular pain occurred after one RFA treatment (4.5%; 1/22). Seven patients hadradiation resistant tumors (renal cell, melanoma, or sarcoma). Post-procedural imaging (median6 months; range 2 – 27 months) showed stable treated disease in 12/13 treatments at 3 monthsand 10/10 at 6 months.Limitations: The therapeutic effect of vertebral augmentation versus percutaneous ablationcannot be separated in this retrospective study. Radiation treatment protocols were variable andincluded both stereotactic body and conventional RT which may have different safety and efficacyprofiles.Conclusion: Percutaneous ablation and concurrent RT is safe and effective in palliating painfulspinal metastases and can be effective in those who have radiation resistant tumor histology.Key words: Interventional spine oncology, pain, percuataneous ablation, radiofrequencyablation, cryoablation, radiation therapy, spine metastases, vertebroplasty