title: Comparison of expandable electrodes in percutaneous radiofrequency ablation of renal cell carcinoma.
abstract: OBJECTIVE
  To compare two different expandable electrodes in radiofrequency ablation of renal cell carcinoma.
  
  
  METHODS
  Percutaneous ablation was performed at two centers using either an expandable 7F umbrella-shaped LeVeen probe (diameter 2-4 cm) and a 200-W generator (group A), or an expandable Starburst XL electrode with a 150-W generator (group B). From each center, eight patients with one tumor each were matched retrospectively with regard to tumor volume, which was 9.71+/-6.43 cm3 for group A and 8.74+/-4.35 cm3 for group B (mean tumor diameter: 2.47+/-0.9 cm versus 2.50+/-0.4 cm, respectively). An unpaired t-test showed no significant difference in tumor volume between the two groups (p=0.820).
  
  
  RESULTS
  Sixteen patients with 16 tumors were treated. The primary technical success of radiofrequency ablation was 94% (15 of 16 patients). After retreatment of residual tumor in one patient from group B, secondary technical success was 100%. No major complications were observed. The resulting mean volume of the almost spherical necroses was 21.1+/-9.1 cm3 versus 14.6+/-6.7 cm3 for groups A and B (diameter of necrosis: 3.5+/-0.7 cm versus 3.1+/-0.6 cm, respectively). A Mann-Whitney U-test showed no significant difference in necrosis volume between the two groups (CI [-0.215; 0.471]; p=0.2892). The calculated shape value of S (ratio of length to height of the coagulation necrosis) was 0.9+/-0.1 and 1.0+/-0.1 for groups A and B, respectively. No local recurrence was observed during a mean follow-up of 14.8+/-11.6 months, while extrarenal tumor progression occurred in three patients.
  
  
  CONCLUSIONS
  No significant differences in coagulation volume and shape were found after RF ablation of renal cell carcinoma using two different expandable electrodes. To avoid local recurrence, however, accurate placement of probes and appropriate expansion of the electrode is necessary.
authors.affiliation: Department of Pediatrics, Medical University Vienna, General Hospital, Währinger Guertel 18-20, A-1090 Vienna, Austria.
authors.forename: Talin
authors.initials: T
authors.lastname: Gulesserian
authors.forename: Andreas H
authors.initials: AH
authors.lastname: Mahnken
authors.forename: Ruediger
authors.initials: R
authors.lastname: Schernthaner
authors.forename: Mazda
authors.initials: M
authors.lastname: Memarsadeghi
authors.forename: Michael
authors.initials: M
authors.lastname: Weber
authors.forename: A
authors.initials: A
authors.lastname: Tacke
authors.forename: Joachim
authors.initials: J
authors.lastname: Kettenbach
mesh_terms: D000368:Aged; D002292:Carcinoma, Renal Cell / Q000473:pathology / Q000601:surgery*; D017115:Catheter Ablation / Q000295:instrumentation*; D004566:Electrodes / Q000145:classification; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D018365:Neoplasm, Residual / Q000601:surgery*; D012189:Retrospective Studies