Development of an animal model for radiofrequency ablation of primary, virally induced hepatocellular carcinoma in the woodchuck.

PURPOSE To develop a consistent and reproducible method in an animal model for studies of radiofrequency (RF) ablation of primary hepatocellular carcinoma (HCC). MATERIALS AND METHODS Fifteen woodchucks were inoculated with woodchuck hepatitis virus (WHV) to establish chronic infections. When serum γ-glutamyl transpeptidase levels became elevated, the animals were evaluated with ultrasound, and, in most cases, preoperative magnetic resonance (MR) imaging to confirm tumor development. Ultimately, RF ablation of tumors was performed by using a 1-cm probe with the animal submerged in a water bath for grounding. Ablation effectiveness was evaluated with contrast-enhanced MR imaging and gross and histopathologic analysis. RESULTS RF ablation was performed in 15 woodchucks. Modifications were made to the initial study design to adapt methodology for the woodchuck. The last 10 of these animals were treated with a standardized protocol using a 1-cm probe that produced a consistent area of tumor necrosis (mean size of ablation, 10.2 mm × 13.1 mm) and led to no complications. CONCLUSIONS A safe, reliable and consistent method was developed to study RF ablation of spontaneous primary HCC using chronically WHV-infected woodchucks, an animal model of hepatitis B virus-induced HCC.