title: Radiofrequency ablation of hepatocellular carcinoma: Mono or multipolar?
abstract: OBJECTIVE
  Thermo-ablation by radiofrequency is recognized as a curative treatment for early-stage hepatocellular carcinoma. However, local recurrence may occur because of incomplete peripheral tumor destruction. Multipolar radiofrequency has been developed to increase the size of the maximal ablation zone. We aimed to compare the efficacy of monopolar and multipolar radiofrequency for the treatment of hepatocellular carcinoma and determine factors predicting failure.
  
  
  METHODS
  A total of 171 consecutive patients with 214 hepatocellular carcinomas were retrospectively included. One hundred fifty-eight tumors were treated with an expandable monopolar electrode and 56 with a multipolar technique using several linear bipolar electrodes. Imaging studies at 6 weeks after treatment, then every 3 months, assessed local effectiveness. Radiofrequency failure was defined as persistent residual tumor after two sessions (primary radiofrequency failure) or local tumor recurrence during follow-up. This study received institutional review board approval (number 2014/77).
  
  
  RESULTS
  Imaging showed complete tumor ablation in 207 of 214 lesions after the first session of radiofrequency. After a second session, only two cases of residual viable tumor were observed. During follow-up, there were 46 local tumor recurrences. Thus, radiofrequency failure occurred in 48/214 (22.4%) cases. By multivariate analysis, technique (P < 0.001) and tumor size (P = 0.023) were independent predictors of radiofrequency failure. Failure rate was lower with the multipolar technique for tumors < 25 mm (P = 0.023) and for tumors between 25 and 45 mm (P = 0.082). There was no difference for tumors ≥ 45 mm (P = 0.552).
  
  
  CONCLUSIONS
  Compared to monopolar radiofrequency, multipolar radiofrequency improves tumor ablation with a subsequent lower rate of local tumor recurrence.
authors.affiliation: Department of Radiology, University Hospital, Angers, France.
authors.forename: Victoire
authors.initials: V
authors.lastname: Cartier
authors.affiliation: Department of Hepato-Gastroenterology, University Hospital, Angers, France.|HIFIH, UPRES 3859, SFR 4208, LUNAM University, Angers, France.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Boursier
authors.affiliation: Department of Radiology, University Hospital, Angers, France.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Lebigot
authors.affiliation: Department of Hepato-Gastroenterology, University Hospital, Angers, France.|HIFIH, UPRES 3859, SFR 4208, LUNAM University, Angers, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Oberti
authors.affiliation: Department of Hepato-Gastroenterology, University Hospital, Angers, France.|HIFIH, UPRES 3859, SFR 4208, LUNAM University, Angers, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Fouchard-Hubert
authors.affiliation: Department of Radiology, University Hospital, Angers, France.|HIFIH, UPRES 3859, SFR 4208, LUNAM University, Angers, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Aubé
mesh_terms: D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000473:pathology / Q000601:surgery*; D017115:Catheter Ablation / Q000379:methods*; D004566:Electrodes; D005260:Female; D005500:Follow-Up Studies; D005544:Forecasting; D006801:Humans; D008113:Liver Neoplasms / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology / Q000517:prevention & control; D017211:Treatment Failure
keywords: hepatocellular carcinoma; local tumor recurrence; multipolar radiofrequency