title: Microwave versus Radiofrequency Ablation Treatment for Hepatocellular Carcinoma: A Comparison of Efficacy at a Single Center.
abstract: OBJECTIVE
  To compare efficacy and major complication rates of radiofrequency (RF) and microwave (MW) ablation for treatment of hepatocellular carcinoma (HCC).
  
  
  METHODS
  This retrospective single-center study included 69 tumors in 55 patients treated by RF ablation and 136 tumors in 99 patients treated by MW ablation between 2001 and 2013. RF and MW ablation devices included straight 17-gauge applicators. Overall survival and rates of local tumor progression (LTP) were evaluated using Kaplan-Meier techniques with Cox proportional hazard ratio (HR) models and competing risk regression of LTP.
  
  
  RESULTS
  RF and MW cohorts were similar in age (P = .22), Model for End-Stage Liver Disease score (P = .24), and tumor size (mean 2.4 cm [range, 0.6-4.5 cm] and 2.2 cm [0.5-4.2 cm], P = .09). Median length of follow-up was 31 months for RF and 24 months for MW. Rate of LTP was 17.7% with RF and 8.8% with MW. Corresponding HR from Cox and competing risk models was 2.17 (95% confidence interval [CI], 1.04-4.50; P = 0.04) and 2.01 (95% CI, 0.95-4.26; P = .07), respectively. There was improved survival for patients treated with MW ablation, although this was not statistically significant (Cox HR, 1.59 [95% CI, 0.91-2.77; P = .103]). There were few major (≥ grade C) complications (2 for RF, 1 for MW; P = .28).
  
  
  CONCLUSIONS
  Treating HCC percutaneously with RF or MW ablation was associated with high primary efficacy and durable response, with lower rates of LTP after MW ablation.
authors.affiliation: Departments of Radiology, University of Wisconsin School of Medicine and Public Health, 600 Highland Avenue, E3/366, Madison, WI 53792-3252.
authors.forename: Theodora A
authors.initials: TA
authors.lastname: Potretzke
authors.affiliation: Departments of Radiology, University of Wisconsin School of Medicine and Public Health, 600 Highland Avenue, E3/366, Madison, WI 53792-3252.. Electronic address: tziemlewicz@uwhealth.org.
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Ziemlewicz
authors.affiliation: Departments of Radiology, University of Wisconsin School of Medicine and Public Health, 600 Highland Avenue, E3/366, Madison, WI 53792-3252.
authors.forename: J Louis
authors.initials: JL
authors.lastname: Hinshaw
authors.affiliation: Departments of Radiology, University of Wisconsin School of Medicine and Public Health, 600 Highland Avenue, E3/366, Madison, WI 53792-3252.
authors.forename: Meghan G
authors.initials: MG
authors.lastname: Lubner
authors.affiliation: Departments of Radiology, University of Wisconsin School of Medicine and Public Health, 600 Highland Avenue, E3/366, Madison, WI 53792-3252.
authors.forename: Shane A
authors.initials: SA
authors.lastname: Wells
authors.affiliation: Departments of Radiology, University of Wisconsin School of Medicine and Public Health, 600 Highland Avenue, E3/366, Madison, WI 53792-3252.; Biomedical Engineering, University of Wisconsin School of Medicine and Public Health, 600 Highland Avenue, E3/366, Madison, WI 53792-3252; Medical Physics (C.L.B.), University of Wisconsin School of Medicine and Public Health, 600 Highland Avenue, E3/366, Madison, WI 53792-3252.
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Brace
authors.affiliation: Medicine, Section of Hepatology, (P.A.), University of Wisconsin School of Medicine and Public Health, 600 Highland Avenue, E3/366, Madison, WI 53792-3252.
authors.forename: Parul
authors.initials: P
authors.lastname: Agarwal
authors.affiliation: Departments of Radiology, University of Wisconsin School of Medicine and Public Health, 600 Highland Avenue, E3/366, Madison, WI 53792-3252.; Biomedical Engineering, University of Wisconsin School of Medicine and Public Health, 600 Highland Avenue, E3/366, Madison, WI 53792-3252.
authors.forename: Fred T
authors.initials: FT
authors.lastname: Lee
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D017115:Catheter Ablation / Q000009:adverse effects / Q000401:mortality; D018450:Disease Progression; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008113:Liver Neoplasms / Q000000981:diagnostic imaging / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D008297:Male; D008872:Microwaves / Q000009:adverse effects / Q000627:therapeutic use*; D008875:Middle Aged; D011183:Postoperative Complications / Q000209:etiology; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome; D014922:Wisconsin; D055815:Young Adult