Search

Purpose: To compare the accumulation and effect of liposomal doxorubicin in liver tissue treated by radiofrequency ablation (RFA) and irreversible electroporation (IRE) in in vivo porcine models., Materials and Methods: Sixteen RFA and 16 IRE procedures were performed in healthy liver of two groups of three pigs. Multi-tined RFA parameters included: 100 W, target temperature 105°C for 7 min. 100 IRE pulses were delivered using two monopolar electrodes at 2250 V, 1 Hz, for 100 µsec. For each group, two pigs received 50 mg liposomal doxorubicin (0.5 mg/kg) as a drip infusion during ablation procedure, with one pig serving as control. Samples were harvested from the central and peripheral zones of the ablation at 24 and 72 h. Immunohistochemical analysis to evaluate the degree of cellular stress, DNA damage, and degree of apoptosis was performed. These and the ablation sizes were compared. Doxorubicin concentrations were also analyzed using fluorescence photometry of homogenized tissue., Results: RFA treatment zones created with concomitant administration of doxorubicin at 24 h were significantly larger than controls (2.5 ± 0.3 cm vs. 2.2 ± 0.2 cm; p = 0.04). By contrast, IRE treatment zones were negatively influenced by chemotherapy (2.2 ± 0.4 cm vs. 2.6 ± 0.4 cm; p = 0.05). At 24 h, doxorubicin concentrations in peripheral and central zones of RFA were significantly increased in comparison with untreated parenchyma (0.431 ± 0.078 µg/g and 0.314 ± 0.055 µg/g vs. 0.18 ± 0.012 µg/g; p < 0.05). Doxorubicin concentrations in IRE zones were not significantly different from untreated liver (0.191 ± 0.049 µg/g and 0.210 ± 0.049 µg/g vs. 0.18 ± 0.012 µg/g)., Conclusions: Whereas there is an increased accumulation of periprocedural doxorubicin and an associated increase in ablation zone following RFA, a contrary effect is noted with IRE. These discrepant findings suggest that different mechanisms and synergies will need to be considered in order to select optimal adjuvants for different classes of ablation devices.

Radiofrequency ablation and irreversible electroporation are both interventional procedures used in treating cancer diseases generally and may be used in treatment of liver cancer. The two differ in terms of their action and thermal effects. The present study examined thermal effects of radiofrequency ablation and modified irreversible electroporation ex vivo in porcine liver. Standard radiofrequency ablation was used during the experiments, as was a unique, experimental high-voltage generator of the research team's own construction coupled with a newly designed balloon electrode catheter for irreversible electroporation. The tested balloon catheter was newly designed for application in the biliary tract. The temperature of porcine liver tissue was monitored without contact by infrared camera. The results show significantly different temperature of tissue around electrodes for radiofrequency ablation and irreversible electroporation. The data obtained from radiofrequency ablation with maximum tested output power of 10 watts show a symmetrical area of tissue near active electrodes with temperature increased by more than 30 °C. Irreversible electroporation methods showed temperature increasing approximately by 5 °C. To summarize, the thermal research showed that the difference between standard RFA and innovated IRE with the balloon catheter lies not just in the differing mechanism of action, as is well known, but also in its thermal effects. There was documented that tissue temperature was much higher for RFA than for IRE, particularly for the maximum tested output parameters. The applicability of the newly designed balloon catheters was confirmed. [ABSTRACT FROM AUTHOR]