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


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 degrees C for 8 minutes with a 5-mm tumor margin target temperature of 60 degrees C (N = 20); (2) cryoablation using a 15 minute 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 degrees 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 x 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)


CONCLUSIONS
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.
Nakada
Stephen Y
SY
Department of Surgery, The University of Wisconsin Medical School, Madison, Wisconsin, USA. nakada@surgery.wisc.edu
Jerde
Travis J
TJ
Warner
Thomas F
TF
Lee
Fred T
FT
D000818:Animals; D002277:Carcinoma / Q000473:pathology / Q000601:surgery*; D017115:Catheter Ablation; D003452:Cryosurgery; D007680:Kidney Neoplasms / Q000473:pathology / Q000601:surgery*; D009392:Nephrectomy; D011817:Rabbits; D011897:Random Allocation