Effect of healthy tissue ablation surrounding VX2 rabbit liver tumors by high-intensity focused ultrasound combined with an ultrasound contrast agent.

Objectives: The purpose of this study was to determine the minimum amount of healthy peripheral tissue that should be ablated when treating VX2 liver tumors with high-intensity focused ultrasound combined with an ultrasound contrast agent.

Methods: Fifty-one rabbits with hepatic tumors were established and randomly divided into the following groups: group A, which only had their tumors ablated; group B, which had their tumors and 2 mm of healthy adjacent tissue ablated; and group C, which had their tumors and 4 mm of healthy adjacent tissue ablated. The pathologic characteristics of the target tissue, serum alanine aminotransferase (ALT) level, presence of intrahepatic and distant metastases, and survival time between different groups were compared after high-intensity focused ultrasound treatment.

Results: After ablation, coagulative necrosis was observed in all targeted tissue. The serum ALT level in group C was the highest and the level in group A was the lowest on the third and fifth days after ablation (P < .05), respectively. Fourteen days later, the serum ALT level in groups B and C decreased to normal, whereas the level in group A was abnormal and significantly higher (P < .05). Compared with group A, the prevalence of metastases in groups B and C was significantly lower (P < .05), and the survival time was significantly longer (P < .05); there appeared to be no statistically significant difference between groups B and C (P > .05).

Conclusions: Ablation of a tumor along with 2 mm of healthy surrounding tissue is a more effective strategy for treating hepatic cancer with high-intensity focused ultrasound coupled with an ultrasound contrast agent.