No-touch Radiofrequency Ablation of VX2 Hepatic Tumor In Vivo in Rabbits: A proof of concept study

Abstract

Purpose In a proof of concept study, we attempted to compare no-touch radiofrequency ablation (RFA) technique in a bipolar mode with conventional direct tumor puncture technique regarding local tumor control, peritoneal seeding and tumorigenic factor in rabbit VX2 subcapsular hepatic tumor model.

Materials and Methods Sixty-two rabbits with VX2 hepatic subcapsular tumor were divided into three groups: Group A (n=25) with direct tumor puncture RFA (dtpRFA)

Group B (n=25) with no-touch RFA (ntRFA)

Group C (n=12) as a control group. Each three groups were subdivided into two sets either for pathologic analysis (n=24) or CT follow-up until 6-weeks after RFA (n=38). Ultrasonography-guided dtpRFA and ntRFA were performed after nine days of tumor implantation. Local tumor control of RFA was determined by either achievement of complete tumor necrosis on histopathologic exam or absence of local tumor progression (LTP) on follow-up CT and autopsy. The development of peritoneal seeding was also compared among the animal groups. Serum hepatocyte growth factor (HGF), vascular endothelial growth factor (VEGF) and interleukin-6 (IL-6) on day 1, day 2, and day 3 after RFA were measured by ELISA assay for tumorigenic factor evaluation.

Results Regarding local tumor control, there was a trend with group B (80%, 20/25) for the better ablation than group A (56%, 14/25) (P=0.07). Complete tumor necrosis was achieved in 54.5% of group A animals (6/11) and 90.9% of group B animals (10/11). Peritoneal seeding after RFA was significantly more common in group A (71.4%, 10/14) than B (21.4%, 3/14) (P=0.021) or group C (0%). The elevation of HGF, VEGF and IL-6 were not detected in all three groups.

Conclusion NtRFA developed lower rates of peritoneal seeding and showed a tendency to achieve better local tumor control compared to those of dtpRFA.