Hybrid Therapy (Surgery and Radiosurgery) for the Treatment of Renal Cell Carcinoma Spinal Metastases.

BACKGROUND: The management of spinal metastatic renal cell carcinoma (mRCC) is controversial regarding extent of resection and radiation dosing. OBJECTIVE: To determine outcomes in patients treated with hybrid therapy (separation surgery plus adjuvant stereotactic body radiation therapy [SBRT]) for mRCC. METHODS: A retrospective study of a prospectively collected cohort of patients undergoing hybrid therapy for mRCC between 2003 and 2017 was performed. SBRT was delivered as high-dose single-fraction, high-dose hypofractionated, or low-dose hypofractionated. Extent of disease, clinical and operative outcomes, and complications data were collected, and associations with overall survival (OS) and progression-free survival were determined. RESULTS: Ninety patients with mRCC with high-grade epidural spinal cord compression (ESCC grades 2 and 3) were treated. Metastases were widespread, oligometastatic, and solitary in 56%, 33%, and 11% of patients, respectively. SBRT delivered was high-dose single-fraction, high-dose hypofractionated, and low-dose hypofractionated in 24%, 56%, and 20% of patients, respectively. The 1-yr cumulative incidence of major complications was 3.4% (95% confidence interval [CI]: 0.0%-7.2%). The median follow-up was 14.2 mo for the entire cohort and 38.3 mo for survivors. The 1-yr cumulative incidence of progression was 4.6% (95% CI: 0.2%-9.0%), which translates to a local control rate of 95.4% (95% CI: 91.0%-99.8%) 1 yr after surgery. The median OS for the cohort was 14.8 mo. CONCLUSION: These data support the use of hybrid therapy as a safe and effective strategy for the treatment of renal cell spine metastases.