Kurokohchi 31-10

We have previously reported that the combination therapy of percutaneous ethanol injection and radiofrequency ablation (PEI-RFA) was more effective than RFA alone to induce wider coagulated necrosis for the treatment of hepatocellular carcinoma (HCC). In the present study, the effect of time-lag performance of RFA after PEI was evaluated under the same ablation condition as PEI-RFA by analyzing the volume of coagulated necrosis, the energy requirement for ablation and the amount of ethanol injected into HCC. The comparative study between time-lag PEI-RFA and no timelag PEI-RFA showed that the total energy requirement and the energy requirement per unit volume for whole and marginal coagulated necrosis were significantly smaller in the time-lag group than in the no time-lag PEI-RFA group. In time-lag PEI-RFA, the volume of coagulated necrosis induced positively correlated with the amount of ethanol injected into HCC as previously observed in PEI-RFA treatment. These results suggest that time-lag PEI-RFA can induce comparable coagulated necrosis with a smaller energy requirement than no time-lag PEI-RFA, and that time-lag PEI-RFA is likely to be less invasive than no time-lag PEI-RFA for inducing comparable coagulated necrosis. Thus, time-lag performance of RFA after PEI may make RFA treatment more effective and less invasive for the treatment of patients with HCC. Introduction Hepatocellular carcinoma (HCC) is a common malignancy worldwide. For the treatment of HCC, several treatment modalities, such as surgical resection, intervention radiology, liver transplantation and local ablation, are applied according to the characteristics of the tumor and the degree of hepatic reserve capacity. For the patients with HCC for whom surgical treatment is not suitable, local treatments are an option. As local treatments, percutaneous ethanol injection (PEI), percutaneous acetate injection (PAI), percutaneous microwave coagulation therapy (PMCT), cryoablation and radiofrequency ablation (RFA) are currently available (1,2). Among the local treatments, PEI and PAI are considered to be effective for the treatment of patients with relatively small-sized encapsulated HCC of <3 cm in diameter. Instead of PEI, which was more frequently performed in the past, RFA now plays a central role in local treatments because it can induce wider coagulated necrosis in fewer sessions than PEI or PAI (3-5). Although RFA has various benefits, such as simplicity and ease of performance, achievement of certain therapeutic effects (6,7), lack of serious side-effects and, more importantly, longer survival intervals than PEI (8,9), the extent of coagulated necrosis induced by RFA is limited and early local tumor recurrence frequently occurs (10). To overcome these weaknesses of routine RFA treatment, we developed a combination therapy of PEI and RFA (PEI-RFA) and reported that PEIRFA could induce wider coagulated necrosis with a smaller energy requirement (11-13). The present study analyzing the effectiveness of PEI-RFA was triggered by an accidental event that happened when PEI-RFA was performed on HCC using an RFA system equipped with an expandable LeVeen needle electrode. When the ablation was about to start, immediately after ethanol injection, the RFA system did not work due to machine trouble. It took several minutes for the RFA system to be fixed and the ablation started approximately 5 min after the ethanol injection. This RFA system is equipped with an impedance monitoring system and the energy is continuously INTERNATIONAL JOURNAL OF ONCOLOGY 28: 971-976, 2006 971 Time-lag performance of radiofrequency ablation after percutaneous ethanol injection for the treatment of hepatocellular carcinoma KAZUTAKA KUROKOHCHI1,2, TSUTOMU MASAKI1, SEISHIRO WATANABE1, SEIJI NAKAI1, AKIHIRO DEGUCHI1, ASAHIRO MORISHITA1, HIROHITO YONEYAMA1, TOMOHIRO OHGI1,2, MASAHIRO ONO1,2, AKIRA YOSHITAKE1,2, TAKESHI KAKO2, NAOKO OHMACHI2, TAKAAKI KIUCHI3, TSUYOSHI MAETA2, MITSUO YOSHIDA2, YOSHIHIRO MORI2, FUMIKAZU KOHI2 and SHIGEKI KURIYAMA1 1Third Department of Internal Medicine, Kagawa University School of Medicine, 1750-1 Ikenobe, Miki-cho, Kita-gun, Kagawa 761-0793; Departments of 2Gastroenterolgy and 3Radiology, KKR Takamatsu Hospital, 4-18 Tenjinmae, Takamatsu, Kagawa 760-0018, Japan Received October 31, 2005; Accepted December 19, 2005 _________________________________________ Correspondence to: Dr Shigeki Kuriyama, Third Department of Internal Medicine, Kagawa University School of Medicine, 1750-1 Ikenobe, Miki-cho, Kita-gun, Kagawa 761-0793, Japan E-mail: [email protected]