title: Radiofrequency ablation for small hepatocellular carcinoma: prospective comparison of internally cooled electrode and expandable electrode.
abstract: OBJECTIVE
  To prospectively compare the effectiveness of radiofrequency (RF) ablation performed by using an internally cooled electrode and an expandable electrode for the treatment of small (< or = 3.0 cm) hepatocellular carcinomas (HCCs).
  
  
  METHODS
  The human subjects research review board at the study institution approved the protocol, and each patient provided informed consent. Seventy-four patients (58 men and 16 women; age range, 41-83 years) with 83 HCC nodules 3 cm or smaller were randomly divided into an internally cooled electrode group (38 patients with 41 nodules) and an expandable electrode group (36 patients with 42 nodules). RF ablation was performed by one individual. Primary technique effectiveness and rates of major complications were evaluated between the two groups with the Fisher exact test. Rates of local tumor progression, overall survival, local progression-free survival, and event-free survival were evaluated by using the Kaplan-Meier method.
  
  
  RESULTS
  The primary technique effectiveness was 95% in the internally cooled electrode group and 93% in the expandable electrode group (P = .51); rates of major complications were 0% and 2.1% per session (P = .50) and 0% and 2.8% per patient (P = .49), respectively. Rates at 1, 2, and 3 years in the internally cooled electrode group versus the expandable electrode group were as follows: local tumor progression, 12% versus 17%, 20% versus 22%, and 20% versus 22% (P = .72, log-rank test); overall survival, 100% versus 94%, 94% versus 92%, and 94% versus 77% (P = .29, log-rank test); local progression-free survival, 87% versus 78%, 73% versus 66%, and 73% versus 46% (P = .27, log-rank test); and event-free survival, 47% versus 44%, 34% versus 22%, and 34% versus 22% (P = .40, log-rank test).
  
  
  CONCLUSIONS
  On the basis of the study findings, RF ablation with an internally cooled electrode needle and an expandable electrode needle has equivalent effectiveness for the treatment of small HCCs.
authors.affiliation: Department of Radiology, Kyoto University Graduate School of Medicine, 54-Kawaharacho, Shogoin, Sakyoku, Kyoto 606-8507, Japan. ksj@kuhp.kyoto-u.ac.jp
authors.forename: Toshiya
authors.initials: T
authors.lastname: Shibata
authors.forename: Toyomichi
authors.initials: T
authors.lastname: Shibata
authors.forename: Yoji
authors.initials: Y
authors.lastname: Maetani
authors.forename: Hiroyoshi
authors.initials: H
authors.lastname: Isoda
authors.forename: Masahiro
authors.initials: M
authors.lastname: Hiraoka
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging / Q000601:surgery*; D017115:Catheter Ablation / Q000295:instrumentation*; D016009:Chi-Square Distribution; D018450:Disease Progression; D004566:Electrodes; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D011446:Prospective Studies; D015641:Radiography, Interventional; D016019:Survival Analysis; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome