Comparison of Radiofrequency Ablation,Cryoablation,and Nephrectomy in Treating Implanted VX-2 Carcinoma in Rabbit Kidneys

Abstract

Purpose

: To compare the efficacy of radiofrequency (RF) ablation, cryoablation, and radical nephrectomy in the treatment of implanted VX-2 carcinoma in rabbit kidneys.

Materials and Methods

: Sixty-eight New Zealand White rabbits were implanted with 1-mm³ segments of VX-2 carcinoma in the left kidney. Seven days after implantation, the tumors were treated with one of the following: (1) RF ablation using a 12-gauge electrode (RITA Medical Systems, Mountain View, CA) at 90°C for 8 minutes with a 5-mm tumor margin target temperature of 60°C (N = 20); (2) cryoablation using a 15minute double-freeze technique with 2.4-mm cryoprobes and the Cryocare system (Endocare Inc., Irvine, CA) with a 5-mm tumor margin target temperature of -20°C (N = 20); (3) open radical nephrectomy (N = 20); or (4) no treatment (controls; N = 8). Rabbits were allowed to survive for a total of 22 days and sacrificed; and the kidneys, lungs, liver, spleen, urinary bladder, and ureter were removed and examined grossly and histologically for tumor.

Results

: Findings in animals sacrificed at 15 days post-treatment showed significant differences between all treatment groups and untreated controls (P < 0.002) Using a 3 2 chi-square comparison, no differences in disease-free survival were observed between the RF ablation group, the cryoablation group, and the open nephrectomy group (P = 0.72)

Conclusion

: Radiofrequency ablation, cryoablation, and radical nephrectomy were all efficacious in the treatment of implanted VX-2 renal tumors compared with untreated controls (P = 0.002). No statistically significant difference was found between any of the three treatments.