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

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Abstract

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 RF 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 cm3 vs 6.2 cm3; P = .001) and 3-cm (32.7 cm3 vs 15.2 cm3; 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 patients 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.

Section snippets

Patient Population

Patients were retrospectively included if they had (i) a single HCC≤3 cm in diameter, (ii) HCC adjacent to the diaphragm (HCCs with margins located<1 cm from the diaphragm), (iii) no imaging evidence of vascular invasion by the tumor, and (iv) no evidence of extrahepatic disease. Patients were excluded if they had (i) multiple HCCs, (ii) the presence of vascular invasion, (iii) extrahepatic metastases, or (iv) coagulopathy (platelet count<50×103/μL; international normalized ratio>1.5). Our

Patient Characteristics

The characteristics of the patients in this study are summarized in Table 1. Of 165 patients, 122 tested positive for hepatitis B virus, 17 tested positive for hepatitis C virus, and 26 tested negative for both hepatitis B virus and hepatitis C virus. At the time of RF ablation, 148 patients had cirrhosis, 9 had chronic hepatitis, and 8 had neither cirrhosis nor chronic hepatitis. Tumor sizes ranged from 0.5–2.8 cm in the IC group and from 0.8–3 cm in the ICW group. There were no significant

Discussion

RF ablation of subphrenic HCCs remains an important therapeutic challenge because of the difficulties in targeting these tumors and creating sufficient safety margins. A comparison of clinical outcomes after percutaneous RF ablation in patients with nonsubphrenic and subphrenic HCCs showed that the latter tended to have decreased rates of technical success (98% vs 84%) and technical effectiveness (98% vs 90%) (19). Most importantly, the local tumor progression rate after RF ablation was

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  • Cited by (0)

    None of the authors have identified a conflict of interest.

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