AJR:186, May 2006 S327 AJR 2006; 186:S327–S333 0361–803X/06/1865–S327 © American Roentgen Ray Society M E D I C A L I M A G I N G A C E N T U R Y O F M E D I C A L I M A G I N G A C E N T U R Y O F Kim et al. Effect of HCC Grade on Ablation Results Radiofrequency Ablation • Original Research Percutaneous Radiofrequency Ablation of Hepatocellular Carcinoma: Effect of Histologic Grade on Therapeutic Results Seong Hyun Kim 1 Hyo K. Lim Dongil Choi Won Jae Lee Seung Hoon Kim Min Ju Kim Chan Kyo Kim Yong Hwan Jeon Jong Mee Lee Hyunchul Rhim Kim SH, Lim HK, Choi D, et al. Keywords: ablation, hepatocellular carcinoma, histologic grade, radiofrequency DOI:10.2214/AJR.05.0350 Received March 1, 2005; accepted after revision June 2, 2005. 1 All authors: Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Ilwon-dong, Kangnam-ku, Seoul 135-710, South Korea. Address correspondence to H. K. Lim (hklim@smc.samsung.co.kr). OBJECTIVE. The purpose of our study was to assess the therapeutic results of radiofre- quency ablation of hepatocellular carcinoma (HCC) based on the histologic grades of the tumors. SUBJECTS AND METHODS. Between April 1999 and December 2003, 95 patients with nodular HCC were treated with percutaneous radiofrequency ablation. All tumors were histologically proven by sonography-guided percutaneous biopsy and were classified as Ed- mondson-Steiner grade I HCC (n = 38) (mean, 2.3 cm) (group 1), grade II HCC (n = 50) (mean, 2.4 cm) (group 2), or grade III HCC (n = 7) (mean, 2.8 cm) (group 3). All patients underwent contrast-enhanced three-phase helical CT examination before and after radiofrequency abla- tion. After retrospective review of the medical records and follow-up CT examinations, the rates of technique effectiveness, local tumor progression, cumulative survival, and cancer-free survival using a Kaplan-Meier method were calculated and compared among the groups. RESULTS. Technique effectiveness rates in groups 1, 2, and 3 were 87% (27/31), 71% (30/42), and 43% (3/7), respectively, with statistical significance (p = 0.032). Local tumor pro- gression rates in groups 1, 2, and 3 were 16% (5/31), 36% (15/42), and 71% (5/7), respectively, with statistical significance (p = 0.013). Five-year cumulative survival rates in groups 1, 2, and 3 were 71%, 44%, and 43%, respectively, with no statistical significance (p > 0.05). Four-year cancer-free survival rates in groups 1, 2, and 3 were 39%, 10%, and 0%, respectively (p < 0.05 for groups 1 vs 2; p > 0.05 for groups 1 vs 3 and groups 2 vs 3). CONCLUSION. The histologic grade of HCC is an important factor influencing thera- peutic results with survival after radiofrequency ablation. adiofrequency ablation is a widely accepted alternative to surgical re- section in the treatment of hepatic tumors, particularly hepatocellu- lar carcinoma (HCC) [1–4]. The technique has been considered safe and promising, es- pecially for the unresectable hepatic tumors that result from multifocal tumors and a lim- ited hepatic functional reserve due to liver cir- rhosis [1, 2, 4, 5]. The crucial advantage of ra- diofrequency ablation is its ability to reduce morbidity and mortality and to preserve more liver parenchymal volume. In addition, the procedure is less technically challenging than surgical resection of hepatic tumors [6]. The therapeutic results of radiofrequency ablation of hepatic tumors are influenced by a variety of factors such as the skill of the oper- ator; the choice of technique; the generator power of the radiofrequency ablation device; and the size, location, and morphology of the tumor [1, 5, 7–10]. We hypothesized that the therapeutic results also could be influenced by the histologic grade of HCC. However, to our knowledge, no study has assessed the therapeutic efficacy of radiofrequency abla- tion according to the histologic grade of HCC. The purpose of this study was to con- duct such an assessment. Subjects and Methods Patient Selection The study was performed with the approval of the institutional review board. Written informed consent was obtained from all patients included in the study. Between April 1999 and December 2003, 727 pa- tients with nodular HCC were referred to our depart- ment for radiofrequency ablation because of poor he- patic functional reserve due to liver cirrhosis, multiple HCC tumors, expected liver cell loss due to resection, refusal of the patient to undergo liver transplantation, or cardiopulmonary dysfunction. Of these patients, 632 were excluded from the study; this excluded group included patients with a history of treatment by hepatic resection, transcatheter arte- rial chemoembolization (TACE), or percutaneous R Downloaded from www.ajronline.org by 52.73.204.196 on 05/17/22 from IP address 52.73.204.196. Copyright ARRS. For personal use only; all rights reserved