Application of radiofrequency ablation of renal VX2 tumors by cooled-tip electrode in a rabbit model

This study has two purposes: (1) To compare the use of tumor cell suspensions and excised tumor tissue for generating renal tumors suitable for radiofrequency ablation (RFA) studies and (2) to assess the effectiveness of RFA for ablation of renal VX2 tumors in a rabbit model.

VX2 tumor masses were used to inoculate 17 rabbits. The renal VX2 tumors of 13 rabbits were subsequently treated with a cooled-tip radiofrequency system at a power of 15 to 30 W for 3 to 6 minutes, and 4 rabbits served as controls. After RFA, rabbits were observed by contrast-enhanced CT to ascertain the ablative range. Rabbits were divided into three groups and sacrificed at 3, 7, and 14 days post-treatment for histopathologic studies.

Both tumor implant methods had a 100% success rate in generating tumors. The average lesion produced was 1.3 x 1.8 x 1.5 cm. Complete tumor ablation occurred in 76.9%, and local tumor growth in 23.1%. Depending on the position of the tumors, the complications after RFA treatment included infarction, perirenal hematoma, hydronephrosis, and abscess. The overall complication rate was 38.5%. In histopathologic studies, a central needle track, tumor coagulation, renal tissue coagulation, peripheral hemorrhage, and an inflammatory layer could be observed.

Application of RFA to destroy renal VX2 tumors in this rabbit model has a relatively high cure rate. It can be used to destroy small renal tumors in a precise and noninvasive manner. We hope to apply this procedure in selected human renal tumors in the future.