Phase II trial of radio frequency ablation of renal cancer: evaluation of the kill zone.
OBJECTIVE
We report on the pathological evaluation of renal tumors after intraoperative radio frequency ablation performed immediately before surgical nephrectomy.


METHODS
Ten patients with renal tumors were enrolled in a prospective, Institutional Review Board approved phase II trial of radio frequency ablation. Following surgical exposure of the kidney a single 12-minute radio frequency ablation of the tumor was performed using the Radionics Cool-tip RF Radio Frequency Ablation System (Radionics, Burlington, Massachusetts). The tumor was then excised via radical or partial nephrectomy. Gross and histological evaluations of the tumor were performed, including evaluation with nicotinamide adenine dinucleotide vital staining.


RESULTS
All 10 tumors were confirmed histologically to be renal cell carcinoma. Mean tumor size was 3.2 cm. (range 1.4 to 8.0). Of the 10 tumors 8 were completely ablated with a mean treatment margin of 6.75 mm. (range 2 to 13). Of the 2 tumors that were incompletely treated 1 never attained a temperature sufficient for tissue destruction and the other measured 8 cm., far exceeding the expected ablation volume of treatment protocol.


CONCLUSIONS
This study represents the initial report of the histological outcome of saline cooled radio frequency ablation of renal tumors. Our data indicate that it can completely destroy renal cancers while transmitting minimal collateral damage to surrounding renal parenchyma. Further investigation is required to determine long-term oncological outcome.
Matlaga
Brian R
BR
Department of Urology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA.
Zagoria
Ronald J
RJ
Woodruff
Ralph D
RD
Torti
Frank M
FM
Hall
M Craig
MC
D000328:Adult; D000368:Aged; D002292:Carcinoma, Renal Cell / Q000473:pathology / Q000601:surgery*; D017115:Catheter Ablation; D006801:Humans; D007680:Kidney Neoplasms / Q000473:pathology / Q000601:surgery*; D008875:Middle Aged; D009392:Nephrectomy; D011446:Prospective Studies