title: Potential of a no-touch pincer ablation procedure that uses a multipolar radiofrequency ablation system to prevent intrasubsegmental recurrence of small and single hepatocellular carcinomas.
abstract: OBJECTIVE
  The aim of this study was to clarify the usefulness of a no-touch pincer ablation procedure that uses bipolar electrodes to prevent intrasubsegmental tumor recurrence after radiofrequency ablation (RFA) for patients with hepatocellular carcinoma (HCC).
  
  
  METHODS
  We studied 303 consecutive patients with HCC (single nodule and tumor diameter ≤30 mm) who received RFA between January 2005 and April 2015; 268 patients received touch ablation using a monopolar or bipolar RFA device, and 35 received no-touch ablation using a bipolar RFA device. The pretreatment arterial and portal phase dynamic computed tomography or magnetic resonance images were classified into four enhancement patterns. Type 1 and Type 2 are homogeneous enhancement patterns without or with increased arterial blood flow, respectively. Type 3 is a heterogeneous enhancement pattern with a septum-like structure, and Type 4 is an irregularly shaped ring structure enhancement pattern.
  
  
  RESULTS
  With regard to intrasubsegmental tumor recurrence, among the 268 patients who underwent the touch ablation procedure, tumors recurred in 52 (19.4%) patients, and among the 35 patients who underwent the no-touch ablation procedure, tumors recurred in one (2.9%) patient. Cumulative intrasubsegmental tumor recurrence rates tended to be higher with touch ablation (P = 0.083). Multivariate Cox proportional hazards analysis revealed that ablation procedure (touch ablation, hazard ratio [HR] 10.32, P = 0.032), type of enhancement pattern (Type 3, HR 3.05, P = 0.006; and Type 4, HR 8.87, P < 0.001) and serum des-γ-carboxyprothrombin level (≥100 AU/L; HR 2.73, P = 0.035) were significant predictors for intrasubsegmental recurrence.
  
  
  CONCLUSIONS
  The no-touch pincer ablation procedure has the potential to prevent intrasubsegmental recurrence after RFA for patients with HCC.
authors.affiliation: Department of Hepatology, Toranomon Hospital, Tokyo, Japan.|Okinaka Memorial Institute for Medical Research, Toranomon Hospital, Tokyo, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Kawamura
authors.affiliation: Department of Hepatology, Toranomon Hospital, Tokyo, Japan.|Okinaka Memorial Institute for Medical Research, Toranomon Hospital, Tokyo, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Ikeda
authors.affiliation: Department of Hepatology, Toranomon Hospital, Tokyo, Japan.|Okinaka Memorial Institute for Medical Research, Toranomon Hospital, Tokyo, Japan.
authors.forename: Shunichiro
authors.initials: S
authors.lastname: Fujiyama
authors.affiliation: Department of Hepatology, Toranomon Hospital, Tokyo, Japan.|Okinaka Memorial Institute for Medical Research, Toranomon Hospital, Tokyo, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Hosaka
authors.affiliation: Department of Hepatology, Toranomon Hospital, Tokyo, Japan.|Okinaka Memorial Institute for Medical Research, Toranomon Hospital, Tokyo, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kobayashi
authors.affiliation: Department of Hepatology, Toranomon Hospital, Tokyo, Japan.|Okinaka Memorial Institute for Medical Research, Toranomon Hospital, Tokyo, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Saitoh
authors.affiliation: Department of Hepatology, Toranomon Hospital, Tokyo, Japan.|Okinaka Memorial Institute for Medical Research, Toranomon Hospital, Tokyo, Japan.
authors.forename: Hitomi
authors.initials: H
authors.lastname: Sezaki
authors.affiliation: Department of Hepatology, Toranomon Hospital, Tokyo, Japan.|Okinaka Memorial Institute for Medical Research, Toranomon Hospital, Tokyo, Japan.
authors.forename: Norio
authors.initials: N
authors.lastname: Akuta
authors.affiliation: Department of Hepatology, Toranomon Hospital, Tokyo, Japan.|Okinaka Memorial Institute for Medical Research, Toranomon Hospital, Tokyo, Japan.
authors.forename: Fumitaka
authors.initials: F
authors.lastname: Suzuki
authors.affiliation: Department of Hepatology, Toranomon Hospital, Tokyo, Japan.|Okinaka Memorial Institute for Medical Research, Toranomon Hospital, Tokyo, Japan.
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Suzuki
authors.affiliation: Department of Hepatology, Toranomon Hospital, Tokyo, Japan.|Okinaka Memorial Institute for Medical Research, Toranomon Hospital, Tokyo, Japan.
authors.forename: Yasuji
authors.initials: Y
authors.lastname: Arase
authors.affiliation: Department of Hepatology, Toranomon Hospital, Tokyo, Japan.|Okinaka Memorial Institute for Medical Research, Toranomon Hospital, Tokyo, Japan.
authors.forename: Hiromitsu
authors.initials: H
authors.lastname: Kumada
keywords: bipolar; hepatocellular carcinoma; multipolar; no-touch ablation; radiofrequency ablation