We characterized
cryoablation as a mode of clinical intervention in adult woodchucks with
hepatocellular carcinoma (HCC). Woodchucks (n = 4) were infected with woodchuck hepatitis virus at birth and developed LI-RADS-5 hypervascular HCC. At 21 mo of age, they underwent ultrasound (US), contrast-enhanced CT (CECT) imaging, and US-guided subtotal
cryoablation (IcePearl 2.1 CX, Galil, BTG) of their largest
tumor (Mean HCC volume of 49 ± 9 cm³).
Cryoablation was performed using two 10-min freeze cycles, each followed by an 8-min thaw cycle. The first woodchuck developed significant
hemorrhage after the procedure and was euthanized. In the other 3 woodchucks, the probe track was cauterized and all 3 completed the study. Fourteen days after ablation, CECT was performed, and woodchucks were euthanized. Explanted
tumors were sectioned using subject-specific, 3D-printed cutting molds. Initial
tumor volume, the size of the
cryoablation ice ball, gross pathology and
hematoxylin and
eosin-stained tissue sections were evaluated. On US, the edges of the solid
ice balls were echogenic with dense acoustic shadowing and average dimensions of 3.1 ± 0.5 × 2.1 ± 0.4 cm and cross-sectional area of 4.7 ± 1.0 cm². On day 14 after
cryoablation, CECT of the 3 woodchucks showed devascularized hypo-attenuating cryolesions with dimensions of 2.8 ± 0.3 × 2.6 ± 0.4 × 2.93 ± 0.7 cm and a cross sectional area of 5.8 ± 1.2 cm². Histopathologic evaluation showed hemorrhagic
necrosis with a central amorphous region of coagulative
necrosis surrounded by a rim of karyorrhectic debris. A rim of approximately 2.5 mm of coagulative
necrosis and fibrous connective tissue clearly demarcated the cryolesion from adjacent HCC. Partial
cryoablation of
tumors produced coagulative
necrosis with well-defined ablation margins at 14 d.
Cauterization appeared to prevent
hemorrhage after
cryoablation of hypervascular
tumors. Our findings indicate that woodchucks with HCC may provide a predictive preclinical model for investigating ablative modalities and developing new combination
therapies.