title: Small- and medium-sized hepatocellular carcinomas: monopolar radiofrequency ablation with a multiple-electrode switching system-mid-term results.
abstract: OBJECTIVE
  To prospectively assess the safety and mid-term therapeutic effectiveness of monopolar radiofrequency (RF) ablation with a multiple-electrode switching system for treating small- and medium-sized (≤ 5 cm) hepatocellular carcinomas (HCCs).
  
  
  METHODS
  The institutional review board approved this prospective study, and all patients gave informed consent. From February 2009 to January 2010, 166 patients (110 men and 56 women; age range, 38-86 years; mean age, 62 years ± 10 [standard deviation]) with 166 HCCs less than or equal to 5 cm in diameter were treated with monopolar RF ablation with a multiple-electrode switching system. One of three experienced radiologists performed the RF ablation. Technique effectiveness, ablation volume and time, and major complications were evaluated by means of computed tomography (CT) immediately after RF ablation and at follow-up CT examinations at 1 month and then every 3 months after the procedure. The overall survival, disease-free survival, and local tumor progression-free survival rates were evaluated by using the Kaplan-Meier method.
  
  
  RESULTS
  The technique effectiveness rate determined 1 month after RF ablation was 99.4%. Mean ablation parameters were as follows: volume, 85 cm(3) ± 54; maximum diameter, 61 mm ± 13; and minimum diameter, 43 mm ± 11. The major complication rate was 4.8%. The 6-month and 1-, 2-, and 3-year local tumor progression rates were 2%, 6%, 10%, and 11%, respectively. The overall survival rates at 1, 2, and 3 years after RF ablation were 99%, 97%, and 96%, and corresponding local tumor progression-free survival rates were 94%, 90%, and 89%, respectively. The disease-free survival rates at 1, 2, and 3 years after RF ablation were 75%, 60%, and 54%, respectively.
  
  
  CONCLUSIONS
  Monopolar RF ablation with a multiple-electrode switching system in small- and medium-sized HCCs was safe and efficient, and it provided successful local tumor control and high local tumor progression-free survival rates because an adequate ablation volume was obtained.
authors.affiliation: Department of Radiology and Institute of Radiation Medicine, Seoul National University College of Medicine, 28 Yeongon-dong, Jongno-gu, Seoul 110-744, Korea.
authors.forename: Sungmin
authors.initials: S
authors.lastname: Woo
authors.forename: Jeong Min
authors.initials: JM
authors.lastname: Lee
authors.forename: Jeong Hee
authors.initials: JH
authors.lastname: Yoon
authors.forename: Ijin
authors.initials: I
authors.lastname: Joo
authors.forename: Se Hyung
authors.initials: SH
authors.lastname: Kim
authors.forename: Jae Young
authors.initials: JY
authors.lastname: Lee
authors.forename: Jung Hwan
authors.initials: JH
authors.lastname: Yoon
authors.forename: Yoon Jun
authors.initials: YJ
authors.lastname: Kim
authors.forename: Joon Koo
authors.initials: JK
authors.lastname: Han
authors.forename: Byung Ihn
authors.initials: BI
authors.lastname: Choi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery*; D017115:Catheter Ablation / Q000379:methods*; D003287:Contrast Media / Q000008:administration & dosage; D005260:Female; D006801:Humans; D007472:Iohexol / Q000008:administration & dosage / Q000031:analogs & derivatives; D008113:Liver Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications; D016016:Proportional Hazards Models; D011446:Prospective Studies; D015996:Survival Rate; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
chemical_list: D003287:Contrast Media; D007472:Iohexol; C038192:iopromide