title: Needle tract seeding after radiofrequency ablation of hepatic tumors.
abstract: OBJECTIVE
  To determine the incidence and risk factors associated with needle tract seeding after radiofrequency ablation (RFA) of liver tumors.
  
  
  METHODS
  A prospective data base of patients with hepatic tumors treated by RFA from December 1999 until August 2003 was reviewed to identify patients with needle tract seeding. During this period, 200 patients (148 men, 52 women) with 299 lesions underwent 298 treatment sessions. Patients with both primary (153 hepatocellular carcinoma, two cholangiocarcinoma) and a variety of secondary tumors (35 colorectal, 10 other) were treated. RFA was performed percutaneously with computed tomography (CT) and/or ultrasound (US) guidance, or with US guidance at laparoscopy or laparotomy. All procedures were performed with a LeVeen needle electrode. The needle tract was not routinely coagulated or embolized.
  
  
  RESULTS
  Eight patients out of 200 (4%) were identified with needle tract seeding, based on imaging findings or surgical reintervention. This corresponds to a rate of eight of 298 (2.7%) per treatment session and eight of 299 (2.7%) per lesion. Statistically significant risk factors for neoplastic seeding included treatment of a subcapsular lesion (OR = 11.57, P = .007), multiple treatment sessions (OR = 2.0, P = .037), and multiple electrode placements (OR = 1.4, P = .006).
  
  
  CONCLUSIONS
  Neoplastic seeding may occur after RFA of liver tumors. The results show that the frequency of this complication is not insignificant, and are at the upper end of rates reported in the literature of 0.5% to 2.8%. Specific risk factors identified in this study include treatment of subcapsular lesions, patients treated in multiple sessions, and lesions requiring more than one electrode placement.
authors.affiliation: Department of Medical Imaging, University Health Network and Mount Sinai Hospital, 600 University Avenue, Suite 1225, Toronto, ON, Canada, M5G 1X5.
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Jaskolka
authors.forename: Murray R
authors.initials: MR
authors.lastname: Asch
authors.forename: John R
authors.initials: JR
authors.lastname: Kachura
authors.forename: Chia S
authors.initials: CS
authors.lastname: Ho
authors.forename: Marc
authors.initials: M
authors.lastname: Ossip
authors.forename: Florence
authors.initials: F
authors.lastname: Wong
authors.forename: Morris
authors.initials: M
authors.lastname: Sherman
authors.forename: David R
authors.initials: DR
authors.lastname: Grant
authors.forename: Paul D
authors.initials: PD
authors.lastname: Greig
authors.forename: Steven
authors.initials: S
authors.lastname: Gallinger
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006528:Carcinoma, Hepatocellular / Q000556:secondary / Q000601:surgery; D017115:Catheter Ablation / Q000009:adverse effects* / Q000295:instrumentation; D018281:Cholangiocarcinoma / Q000556:secondary / Q000601:surgery; D004566:Electrodes / Q000009:adverse effects; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D010535:Laparoscopy; D007813:Laparotomy; D008113:Liver Neoplasms / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009339:Needles / Q000009:adverse effects; D009366:Neoplasm Seeding; D011446:Prospective Studies; D015641:Radiography, Interventional; D012307:Risk Factors; D014057:Tomography, X-Ray Computed; D018084:Ultrasonography, Interventional