Irreversible Electroporation of Prostate Cancer: Patient-Specific Pretreatment Simulation by Electric Field Measurement in a 3D Bioprinted Textured Prostate Cancer Model to Achieve Optimal Electroporation Parameters for Image-Guided Focal Ablation

Excerpt

Irreversible electroporation (IRE) of localized prostate cancer (PCA) for curatively intended treatment is still considered experimental, though first study results confirm its high developmental potential as an organ- and function-preserving focal therapy. Current limitations thus far include exact calculation of the ablation field, congruence between tumor localization and extension of the ablation field, and organ confinement of the ablation field with sparing of structures/organs at risk. Van den Bos et al. [1], for example, described the ablation field as being two-to-three times larger than expected and extending beyond the prostatic capsule into the neurovascular bundle with the corresponding risks of stress incontinence and erectile dysfunction. Two important factors are discussed. For one thing, electric field configuration strongly depends on tissue heterogeneity and conductivity [2]. The aging prostate with PCA is a very inhomogeneous tissue or organ (PCA, nodular hyperplasia, inflammatory infiltrates, cysts, prostatoliths, urethra, anatomic zones, and capsule). IRE planning with the NanoKnife system, however, developmentally assumes the target tissue to be homogeneous and not organ specific. This limits individual tissue-texture-related prostate-specific IRE ablation planning. For another thing, a spheroidal IRE field coaxially aligned with the needle electrodes in the longitudinal axis is generated in transperineal grid-directed IRE of the prostate. However, the prostate displays pyramidal-to-spheroid asymmetry. Moreover, PCA is often characterized by multifocal, peripheral, asymmetric, nonspheroidal, and capsule-infiltrating or transmural growth (apex, not capsule). This makes it very difficult to adjust the IRE ablation field to tumor and prostate geometry, especially in the peripheral areas. Previous approaches to mathematical pretreatment simulation and intra-interventional monitoring by electrical impedance tomography could not be clinically implemented to solve the problem [3, 4]. …