title: Preliminary Outcome of Microwave Ablation of Hepatocellular Carcinoma: Breaking the 3-cm Barrier?
abstract: OBJECTIVE
  To evaluate preliminary outcomes after microwave ablation (MWA) of hepatocellular carcinoma (HCC) up to 5 cm and to determine the influence of tumor size.
  
  
  METHODS
  Electronic records were searched for HCC and MWA. Between January 2011 and September 2014, 173 HCCs up to 5 cm were treated by MWA in 129 consecutive patients (89 men, 40 women; mean age, 66.9 y ± 9.5). Tumor characteristics related to local tumor progression and primary and secondary treatment efficacy were evaluated by univariate analysis. Outcomes were compared between tumors ≤ 3 cm and tumors > 3 cm.
  
  
  RESULTS
  Technical success, primary efficacy, and secondary efficacy were 96.5%, 99.4%, and 94.2% at a mean follow-up period of 11.8 months ± 9.8 (range, 0.8-40.6 mo). Analysis of tumor characteristics showed no significant risk factor for local tumor progression, including subcapsular location (P = .176), tumor size (P = .402), and perivascular tumor location (P = .323). The 1-year and 2-year secondary or overall treatment efficacy rates for tumors measuring ≤ 3 cm were 91.2% and 82.1% and for tumors 3.1-5 cm were 92.3% and 83.9% (P = .773). The number of sessions to achieve secondary efficacy was higher in the larger tumor group (1.13 vs 1.06, P = .005). There were three major complications in 134 procedures (2.2%).
  
  
  CONCLUSIONS
  With use of current-generation MWA devices, percutaneous ablation of HCCs up to 5 cm can be achieved with high efficacy.
authors.affiliation: Department of Radiology, David Geffen School of Medicine at the University of California, Los Angeles, California; Department of Radiology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Somrach
authors.initials: S
authors.lastname: Thamtorawat
authors.affiliation: Albert Einstein College of Medicine, Bronx, New York.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Hicks
authors.affiliation: Department of Radiology, David Geffen School of Medicine at the University of California, Los Angeles, California.
authors.forename: Jenifer
authors.initials: J
authors.lastname: Yu
authors.affiliation: Department of Radiology, Chulabhorn Hospital, Bangkok, Thailand.
authors.forename: Surachate
authors.initials: S
authors.lastname: Siripongsakun
authors.affiliation: Department of Radiology, David Geffen School of Medicine at the University of California, Los Angeles, California; Department of Radiology, Cathay General Hospital, Taipei, Taiwan; School of Medicine, Fu-Jen Catholic University, New Taipei City, Taiwan.
authors.forename: Wei-Chan
authors.initials: WC
authors.lastname: Lin
authors.affiliation: Department of Radiology, David Geffen School of Medicine at the University of California, Los Angeles, California.
authors.forename: Steven S
authors.initials: SS
authors.lastname: Raman
authors.affiliation: Department of Radiology, David Geffen School of Medicine at the University of California, Los Angeles, California.
authors.forename: Justin P
authors.initials: JP
authors.lastname: McWilliams
authors.affiliation: Department of Radiology, David Geffen School of Medicine at the University of California, Los Angeles, California.
authors.forename: Michael
authors.initials: M
authors.lastname: Douek
authors.affiliation: Department of Radiology, David Geffen School of Medicine at the University of California, Los Angeles, California.
authors.forename: Simin
authors.initials: S
authors.lastname: Bahrami
authors.affiliation: Department of Radiology, David Geffen School of Medicine at the University of California, Los Angeles, California. Electronic address: dlu@mednet.ucla.edu.
authors.forename: David S K
authors.initials: DS
authors.lastname: Lu
mesh_terms: D055011:Ablation Techniques / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D057286:Electronic Health Records; D004867:Equipment Design; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D008297:Male; D008872:Microwaves / Q000009:adverse effects / Q000627:therapeutic use*; D008875:Middle Aged; D011183:Postoperative Complications / Q000209:etiology; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D047368:Tumor Burden