title: Hepatic tumor ablation with clustered microwave antennae: the US Phase II trial.
abstract: BACKGROUND
  Thermal ablation techniques have become important treatment options for patients with unresectable hepatic malignancies. Microwave ablation (MWA) is a new thermal ablative technique that uses electromagnetic energy to produce coagulation necrosis. We report outcomes from the first clinical trial in the United States using MWA and a 915 MHz generator.
  
  
  METHODS
  Patients with unresectable primary or metastatic liver cancer were enrolled in a multi-institutional trial from March 2004 through May 2006. Demographic information, diagnosis, treatment, and outcomes were documented.
  
  
  RESULTS
  Eighty-seven patients underwent 94 ablation procedures for 224 hepatic tumors. Forty-two ablations (45%) were performed open, 7 (7%) laparoscopically, and 45 (48%) percutaneously. The average tumor size was 3.6 cm (range 0.5-9.0 cm). Single antenna ablation volumes were 10.0 ml (range 7.8-14.0 ml), and clustered antennae ablation volumes were 50.5 ml (range 21.1-146.5 ml). Outcome variables were measured with a mean follow-up of 19 months. Local recurrence at the ablation site occurred in 6 (2.7%) tumors, and regional recurrence occurred in 37 (43%) patients. With a mean follow-up of 19 months, 41 (47%) patients were alive with no evidence of disease. There were no procedure-related deaths. The overall mortality rate was 2.3%.
  
  
  CONCLUSIONS
  Microwave ablation is a safe and effective technology for hepatic tumor ablation. In our study, clustered antennae resulted in larger ablation volumes. Further studies with histological confirmation are needed to verify clinical results.
authors.affiliation: Division of Gastrointestinal and Minimally Invasive Surgery, Carolinas Medical Center, Charlotte, NC 28203, USA. David.Iannitti@carolinashealthcare.org
authors.forename: David A
authors.initials: DA
authors.lastname: Iannitti
authors.forename: Robert C G
authors.initials: RC
authors.lastname: Martin
authors.forename: Caroline J
authors.initials: CJ
authors.lastname: Simon
authors.forename: William W
authors.initials: WW
authors.lastname: Hope
authors.forename: William L
authors.initials: WL
authors.lastname: Newcomb
authors.forename: Kelly M
authors.initials: KM
authors.lastname: McMasters
authors.forename: Damian
authors.initials: D
authors.lastname: Dupuy