Irreversible electroporation: an in vivo study with dorsal skin fold chamber.

Irreversible electroporation (IRE) has been proposed to destroy large amounts of tumorous tissue and shows advantages over thermal therapies. Unfortunately, carefully constructed studies assessing impact in in vivo tumor systems and a direct comparison of IRE with thermal therapy are lacking. In this study, we investigate the effect of IRE in a human prostate cancer (LNCaP) grown in a thin, essentially two-dimensional, dorsal skin fold chamber system. Detailed experimental characterizations of the electrical and thermal responses of the tissue were performed yielding the first thermal response measurement in vivo of its kind that we are aware of. The interaction and coupling of electrical and thermal responses were further discussed. The threshold of the tumor injury was determined for human prostate tumor model, and the threshold value (600-1300 V cm(-1)) is dependent on the IRE parameters including pulse duration and pulse number. This dependence was explained in the context of tissue electrical conductivity change during IRE. Further, the thermal injury was found not to be a dominant factor in IRE with our system, which is in agreement with previous numerical studies. Finally, it appears that the local electrical heterogeneity of the tumor tissue reduces the effectiveness of IRE in some sections of the tumor (leading to live tumor patches).