COST-UTILITY ANALYSIS OF THE CYBERKNIFE SYSTEM FOR METASTATIC SPINAL TUMORS

Abstract

Using decision analysis, a cost-utility study evaluated the cost-effectiveness of CyberKnife (Accuray, Inc., Sunnyvale, CA) stereotactic radiosurgery (SRS) in comparison to external beam radiation therapy in the treatment of metastatic spinal malignancies. The published literature provided evidence on the effectiveness of the comparator interventions in the absence of primary outcomes data. Costs of care were derived from Centers for Medicare and Medicaid Services fee schedules. A Markov model was constructed from the payer perspective to simulate the outcomes of patients undergoing nonchemotherapeutic interventions for metastatic spinal tumors. Because cancer therapies bear significant health and economic consequences, the impact of treatment-related toxicities was integrated into the model. Given the terminal nature of these conditions and the limited life expectancy of the patient population, the time horizon for the analysis was limited to 12 months. Patients treated with CyberKnife SRS gained an additional net health benefit of 0.08 quality-adjusted life year; the calculated cost of CyberKnife SRS was $1933 less than external beam radiation therapy for comparable effectiveness. The incremental cost per benefit for this strategy ($41 500 per quality-adjusted life year) met payers' willingness-to-pay criteria. Cost-utility analysis demonstrated that CyberKnife SRS was a superior, cost-effective primary intervention for patients with metastatic spinal tumors compared with conventional external beam radiation therapy.