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

ObjectiveThe 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). MethodsWe studied 303 consecutive patients with HCC (single nodule and tumor diameter 30mm) 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. ResultsWith 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--carboxyprothrombin level (100AU/L; HR 2.73, P=0.035) were significant predictors for intrasubsegmental recurrence. ConclusionThe no-touch pincer ablation procedure has the potential to prevent intrasubsegmental recurrence after RFA for patients with HCC.