Percutaneous Radiofrequency Ablation with Internally Cooled versus Internally Cooled Wet Electrodes for Small Subphrenic Hepatocellular Carcinomas

Purpose: To compare retrospectively technical effectiveness and complications after radiofrequency (RF) ablation with internally; cooled wet (ICW) electrodes versus conventional internally cooled (IC) electrodes in patients with Small (<= 3 cm) subphrenic hepatocellular carcinomas (HCCs). Materials and Methods: From March 2008 to January 2012, 165 patients, each with a single small subphrenic HCC, were treated with RF ablation using IC (n = 81) or ICW (n = 84) electrodes. Results: After initial RV ablation, technical success was achieved in 88% of patients treated with IC electrodes and 91% of patients treated with ICW electrodes (P = .623). At 1 month, technical effectiveness was achieved in 93% and 99% (P = .061). Mean ablation volume was significantly greater in patients treated with ICW electrodes compared with patients treated with IC electrodes, using 2-cm (14.5 cm(3) vs 6.2 cm(3); P = .001) and 3-cm (32.7 cm(3) vs 15.2 cm(3); P < .001) exposed tips. The 6-month and 1-, 2-, and 4-year local tumor progression rates were significantly lower after RF ablation with;ICW electrodes (5%, 13%, 15%, and 26%) compared with IC electrodes (11%, 24%, 32%, and 35%; P = .044). Major complications occurred in 6% of patient treated with IC electrodes and 2% of patients treated with ICW electrodes. Conclusions: In the treatment of small subphrenic HCCs, percutaneous RF ablation using ICW electrodes results in larger ablation zones and lower rates of local tumor progression than RF ablation using conventional IC electrodes.