1512. Clinical outcomes and local control rates for stereotactic radiosurgery following surgery for metastatic spinal tumors

Authors: Robert Koffie, MD; Laura Van Beaver, BS; Caroline Ayinon, BA; Vijay Yanamadala, MD; Ganesh Shankar, MD, PhD; Kevin Oh, MD; John Shin, MD (Burlington, MA)

Introduction:

Stereotactic radiosurgery (SRS) is increasingly being used in the multimodal management of patients with metastatic disease to the spine, but clinical outcomes and local recurrence rates after post-operative SRS remains unknown.  We present data on post-operative SRS for spinal metastasis. 


Methods:

We identified 63 patients who underwent various types of decompressive spine surgery for metastases followed by SRS at our institution between 2012 and 2017. Demographic information, tumor histology, survival rates, recurrence rates, clinical outcomes and complications were recorded and analyzed.

Results:

The mean age of patients in our cohort was 64 years (range 44-85 years), with 32% female and 68% male. The radiation dose was 18-Gy in 1 fraction using 6 MV photons with a 24-Gy boost to the gross tumor volume. The follow up period range was 3-84 months, with 3-weeks average time between surgery and SRS. Radiographic evaluation following SRS was every 3 months after treatment with CT or MRI. The 1- and 2-year survival rates were 57% and 38% respectively. Overall rate of local recurrence was 12.7% within the follow-up period. Multivariate analysis revealed tumor location (thoracic) and histology (lung carcinoma, colon adenocarcinoma, or melanoma) as significant prognostic factors for local control and overall survival. The surgical and medical complication rates were 14.3% and 19.0% respectively.  The most common complication after SRS was an acute pain flare. The rate of hardware failure was 6.3%, with 3 patients developing procedure-related neurological deficits, but there were no cases of radiation myelopathy. There were no differences in local control if a patient had anterior column reconstruction or not.

Conclusion:

SRS is an effective treatment modality following all types of surgery for metastases, not just separation surgery. SRS should be considered in the post-operative management for spinal metastases given the low side effect profile and low complications.