Defining the electric field threshold optimizing prostate cancer treatment with irreversible electroporation

Irreversible electroporation (IRE) is an innovative procedure that can safely and effectively facilitate the destruction of soft tissue tumors using thermal electric pulses through non-thermal ablation. This success, however, is accompanied by a major challenge to define an IRE electric field threshold for human prostate cancer tissue. A group led by researchers from the United States, United Kingdom and Switzerland collaborated to address this challenge by considering the effects of electroporation on soft tumor tissues’ conductivity and electric field. They report their findings in APL Bioengineering.

To reconstruct ablation volumes and determine the electric field threshold for prostate tumor cell death, the researchers used contrast-enhanced clinical MRI data and created static and dynamic models for the electrodes embedded within the ablation volume. Recognizing that soft tumor tissues changes dynamically, modifying their electrical conductivity properties during treatment, they applied a dynamic conductivity function and matched the ablation volume to the volume encompassed by a specific electric field contour to critically determine the electric field threshold for IRE.

After applying the dynamic conductivity function to a retrospective cohort of patients, they discovered that, for the dynamic model, the IRE field threshold ranges from 412 to 614 V/cm, with an average of 506 ± 66 V/cm. For the static model, the IRE threshold ranges from 277 to 573 V/cm with an average of 422 ± 90 V/cm.

Lead author Sabrina Campelo says that their findings can be instrumental for creating or revising future IRE protocols as IRE becomes a viable treatment option for tumor removal. “By dictating the electric field distribution,” Campelo says, “we can help ensure the most accurate and effective plan for treating cancerous tissue while sparing healthy tissue.”

Source: “An evaluation of irreversible electroporation thresholds in human prostate cancer and potential correlations to physiological measurements,” by Sabrina Campelo, Massimo Valerio, Hashim U. Ahmed, Yipeng Hu, Sara L. Arena, Robert E. Neal II, Mark Emberton, and Christopher B. Arena, APL Bioengineering (2017). The article can be accessed at https://doi.org/10.1063/1.5005828 .