title: Prospective study of a 'popping' sound during percutaneous radiofrequency ablation for hepatocellular carcinoma.
abstract: OBJECTIVE
  To prospectively evaluate the occurrence of a 'popping' sound during radiofrequency (RF) ablation for hepatocellular carcinoma (HCC) and its association with early tumor progression and patient survival.
  
  
  METHODS
  Seventy-six patients with 100 tumors underwent RF ablation by using an internally cooled electrode. A popping sound was defined as an audible sound or tactile vibration detected by the operator during RF ablation. Follow-up ranged from 6 to 38 months (mean, 19 months) and included 3-6 month ultrasonography, serum alpha-fetoprotein measurements, and computed tomography or magnetic resonance imaging. Early local and distant intrahepatic tumor progression within 12 months and survival were analyzed.
  
  
  RESULTS
  A popping sound occurred during 58 of the 100 (58%) tumor ablations. Primary technique effectiveness was achieved in 97 of the 100 (97%) tumors. Major complications occurred in 2 of the 76 patients (2.6%). The cumulative rate of early local tumor progression was 20.8%. At multivariate analysis, early local tumor progression was associated with tumor size larger than 3 cm (odds ratio [OR] = 4.08, P = .012) and inversely associated with a popping sound (OR = 0.267, P = .026). The cumulative rate of early distant intrahepatic tumor progression was 21.4%, and the cumulative survival of the whole cohort at 6, 12, 18, and 24 months was 98.7%, 96%, 92.7%, and 83.6%, respectively. A popping sound was not significantly associated with either early distant intrahepatic tumor progression (P = .341) or patient survival (P = .975).
  
  
  CONCLUSIONS
  A popping sound during RF ablation is not associated with an increased risk of early tumor progression or poorer patient survival.
authors.affiliation: Liver Research Unit, Chang Gung Memorial Hospital, Taipei, Taiwan.
authors.forename: Mark Lee
authors.initials: ML
authors.lastname: Fernandes
authors.forename: Chen-Chun
authors.initials: CC
authors.lastname: Lin
authors.forename: Chun-Jung
authors.initials: CJ
authors.lastname: Lin
authors.forename: Wei-Ting
authors.initials: WT
authors.lastname: Chen
authors.forename: Shi-Ming
authors.initials: SM
authors.lastname: Lin
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006528:Carcinoma, Hepatocellular / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D017115:Catheter Ablation / Q000009:adverse effects*; D016009:Chi-Square Distribution; D018450:Disease Progression; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008113:Liver Neoplasms / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D009622:Noise; D011312:Pressure; D016016:Proportional Hazards Models; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014732:Vibration; D000509:alpha-Fetoproteins / Q000378:metabolism
chemical_list: C097353:AFP protein, human; D000509:alpha-Fetoproteins