The correlation between the electrode configuration and histopathology of irreversible electroporation ablations in prostate cancer patients

Abstract

Purpose Irreversible electroporation (IRE) is a novel minimally invasive therapy for prostate cancer using short electric pulses to ablate prostate tissue. The purpose of this study is to determine the IRE effects in prostate tissue and correlate electrode configuration with the histology of radical prostatectomy (RP) specimens. We hypothesize that the area within the electrode configuration is completely ablated and that the area within the electrode configuration is predictive for the ablated area after treatment.MethodsA prospective phase I/II study was conducted in 16 consecutive patients with histopathologically confirmed prostate cancer scheduled for RP. Focal or extended IRE treatment of the prostate was performed 4 weeks prior to RP. The locations of the electrodes were used to calculate the planned ablation zone. Following RP, the specimens were processed into whole-mount sections, histopathology (PA) was assessed and ablation zones were delineated. The area of the tissue alteration was determined by measuring the surface. The planned and the histological ablation zones were compared, analysed per individual patient and per protocol (focal vs. extended).ResultsAll cells within the electrode configuration were completely ablated and consisted only of necrotic and fibrotic tissue without leaving any viable cells. The histological ablation zone was always larger than the electrodes configuration (2.9 times larger for the 3 electrodes configuration and 2.5 times larger for the ≥4 electrode configuration). These ablation effects extended beyond the prostatic capsule in the neurovascular bundle in 13 out of 15 cases.ConclusionsIRE in prostate cancer results in completely ablated, sharply demarcated lesions with a histological ablation zone beyond the electrode configuration. No skip lesions were observed within the electrode configuration.Clinical trialsClinicalTrials.gov Identifier: NCT01790451 https://clinicaltrials.gov/ct2/show/NCT01790451

Irreversible electroporation for the treatment of localized prostate cancer: a summary of imaging findings and treatment feedback

“…However, the AZVs were larger than the treatment planning. This may be in line with findings after whole mount histopathologic analysis, which showed an extended ablation zone in relation to the electrode configuration, 2.5 to 2.9 times the surface area within the electrode configuration (5). CEUS may show a stronger correlation with the planned AZV than T2-weighted MRI since the 3 mm slice thickness with mpMRI inherently causes less accurate volume measurements.…”

“…Therefore, the extent of the ablation zone cannot be monitored in real-time. In a previous ablate and resect study it was shown that all tissue within the electrode configuration was ablated (5). Therefore, we considered the area within the electrode configuration as the planned AZV.…”

Role of Focal Therapy with High-Intensity Focused Ultrasound in the Management of Clinically Localized Prostate Cancer

“…This may cause significant damage outside the planned boundaries. Such significant extra-boundary damage was also observed in vivo by the group of de la Rosette [26], which questions the precision of this new focal therapy option. Prospective trials on IRE are recruiting and may add evidence to these preliminary observations [27,28].…”

Irreversible electroporation in the curative treatment of Ewing's sarcoma

“…To have the maximum ablative efficacy, probes need to be placed in parallel, with the same depth, 1.7–1.8 cm apart 13. The device loses its efficacy if the probes are not within range.…”