Use of Tumor Necrosis Factor-alpha-coated Gold Nanoparticles to Enhance Radiofrequency Ablation in a Translational Model of Renal Tumors

OBJECTIVES Radiofrequency ablation (RFA) has been most effective when the tumors are small, exophytic, and away from vital structures. We enlarged the size of the ablation kill zone by infusing a 30-nm tumor necrosis factor-alpha and polyethylene glycol-coated gold nanoparticle (CYT-6091, CytImmune Sciences, Inc.) before ablation in a rabbit kidney tumor model. MATERIALS AND METHODS A total of 37 New Zealand White rabbits had VX-2 tumors implanted into their bilateral kidneys; they were then split into 3 treatment groups of 10 rabbits each and a sham group of 7 rabbits as follows: (1) CYT-6091 only, (2) RFA only, (3) CYT-6091 followed 4 hours later by RFA. Gross and microscopic measurements of the ablation size as well as histologic analysis using hematoxylin and eosin staining were performed to determine the effect of CYT-6091 on the ablation. RESULTS The RFA + CYT-6091 group had a larger zone of complete cell death than the RFA-only group when measured on microscopic examination (0.30 +/- 0.07 vs 0.23 +/- 0.03 mL, P = .03). The zone of partially ablated tissue was smaller in the RFA + CYT-6091 group than in the RFA-only group (0.08 +/- 0.02 vs 0.13 +/- 0.05 mL, P = .01). CONCLUSIONS We have demonstrated the efficacy of CYT-6091 in enhancing RFA in a translational kidney tumor model. The potential usage of CYT-6091 to improve RFA of renal cell carcinoma merits further study. UROLOGY 76: 494-599, 2010. (C) 2010 Elsevier Inc.