Radiofrequency ablation of small renal cell carcinomas using multitined expandable electrodes: preliminary experience.
OBJECTIVE
Radiofrequency ablation is a minimally invasive, nephron-sparing option for renal cell carcinoma (RCC) in poor surgical candidates. We report our contemporary experience with RCC radiofrequency ablation using multitined expandable electrodes along with an aggressive treatment strategy to displace adjacent viscera away from probe tines. Involution of the treatment zone was assessed over time.


METHODS
Over a 36-month period, a quality-assurance database identified 22 patients with 26 sporadic RCC who underwent 43 ablations during 27 radiofrequency ablation sessions. The mean age of the cohort was 71 years (range, 47-89 y). Mean RCC diameter was 2.2 cm (range, 1-4 cm). Twenty-six of radiofrequency ablation sessions were performed using multitined expandable electrodes. All ablations used CT guidance with moderate sedation. Adjunctive techniques used during ablation were recorded, as were instances in which ablation mandated penetration of tines beyond the kidney margin. Post-treatment ablation zones were measured from CT/MR images to evaluate serial involution and treatment response.


RESULTS
Technical success in targeting and ablation was 100%. Follow-up periods ranged from 1 to 31 months (mean, 11.2). During this period, one patient presented with marginal local recurrence and underwent repeat radiofrequency ablation. Adjunctive techniques in four patients included water injection for displacement of the tail of the pancreas (n = 1) or descending colon (n = 3). Deliberate penetration of tines beyond the margins of the kidney was performed in 41% of cases; no hemorrhage occurred in these cases. No major complications occurred. Minor complications occurred in 17% of patients, including asymptomatic pneumothorax, perirenal hematomas, subcutaneous hematoma, and subcutaneous abscess. After 6 months, mean involution of the ablation zone was 15% from baseline volume per year.


CONCLUSIONS
Multitined expandable radiofrequency electrodes produce a high rate of local control for small RCCs with a low complication rate, even when tine penetration of the kidney is required for an adequate tumor treatment margin. Adjacent organs can be protected with adjunctive percutaneous maneuvers.
Section of Interventional Radiology, Department of Radiology, University of Pennsylvania School of Medicine, Philadelphia, USA. timothy.clark@med.nyu.edu
Timothy W I
TW
Clark
Bruce
B
Malkowicz
S William
SW
Stavropoulos
Richard
R
Sanchez
Michael C
MC
Soulen
Maxim
M
Itkin
Aalpen
A
Patel
Jeffrey I
JI
Mondschein
A J
AJ
Wein
D000368:Aged; D000369:Aged, 80 and over; D002292:Carcinoma, Renal Cell / Q000601:surgery*; D017115:Catheter Ablation / Q000295:instrumentation*; D004566:Electrodes; D004867:Equipment Design; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications; D012189:Retrospective Studies; D016896:Treatment Outcome