Utilization of Stereotactic Radiosurgery for Renal Cell Carcinoma Brain Metastases

Background: Because renal cell carcinoma (RCC) has been traditionally considered a "radioresistant" histology, it may be advantageous to treat brain metastases (BMs) with ablative dosing by means of stereotactic radiosurgery (SRS). This is the first known analysis evaluating utilization of SRS for RCC BMs in the United States.

Methods: The National Cancer Data Base was queried (2005-2014) for metastatic RCC and delivery of intracranial radiotherapy. Patients were stratified into groups receiving either SRS or non-SRS treatment. Multivariable logistic regression ascertained factors associated with SRS administration. Secondary exploratory Kaplan-Meier overall survival (OS) analysis without and with propensity matching, along with Cox proportional hazards modeling evaluated predictors of OS.

Results: Of 2312 patients, 813 (35%) received SRS, whereas 1499 (65%) received non-SRS radiotherapy. Use of SRS increased from 27% in 2005 to 44% in 2014. Patients receiving SRS tended to reside farther from the treating facility, received therapy at academic centers, and underwent chemotherapy and/or nephrectomy (P < .05). SRS was less often given to persons with lower income and who were uninsured/had Medicaid (P < .05). Higher OS was observed in the SRS cohort both before and following propensity matching; on subset analysis, differences persisted when stratifying for nephrectomy and lack thereof (P < .001 for all). Treatment at an academic center independently predicted for higher OS.

Conclusions: SRS for RCC BMs is rising; this is driven by multiple socioeconomic disparities, which needs to be better addressed to ensure high-quality care for all patients. Treatment with SRS was associated with higher survival; further prospective studies are warranted to confirm these findings.