Yttrium-90 Radioembolization of Renal Cell Carcinoma Metastatic to the Liver

Purpose: To investigate the safety and efficacy of yttrium-90 (Y-90) hepatic radioembolization treatment of patients with liver-dominant metastatic renal cell carcinoma (RCC) refractory to immunotherapy and targeted therapies. Materials and Methods: Between March 2006 and December 2010, six patients with metastatic RCC underwent eight radioembolization treatments with Y-90-labeled resin microspheres for unresectable liver-dominant metastases. All six patients had previous hepatic tumor progression despite targeted therapies or immunotherapies. All had bilobar disease and required whole-liver treatment. Clinical and biochemical toxicities were recorded, and tumor response was assessed every 2-3 months after treatment by cross-sectional imaging. Results: The median dose delivered was 1.89 Gbq (range 0.41-2.03 Gbq). Grade 1 and 2 toxicities were noted in all patients, primarily fatigue. Follow-up imaging was available for five patients. In follow-up periods from 2-64 months (mean 25 months), three patients showed complete responses, and 1 patient showed a partial response by standard imaging criteria, and these patients are alive at 64 months, 55 months, 17 months, and 7 months after treatment. Two patients with rapid progression of disease died within 2 months of treatment, although hepatic malignancy or failure was not the cause of death in either patient. Conclusions: Y-90 radioembolization is a promising option for liver-dominant metastatic RCC with potential for providing long-term survival in patients refractory to or intolerant of targeted therapies.