The field of focal ablative therapy for the treatment of cancer is characterized by abundance of thermal ablative techniques that provide a minimally invasive treatment option in selected tumors. However, the unselective destruction inflicted by thermal ablation modalities can result in damage to vital structures in the vicinity of the tumor. Furthermore, the efficacy of thermal ablation intensity can be impaired due to thermal sink caused by large blood vessels in the proximity of the tumor. Irreversible electroporation (IRE) is a novel ablation modality based on the principle of electroporation or electropermeabilization, in which electric pulses are used to create nanoscale defects in the cell membrane. In theory, IRE has the potential of overcoming the aforementioned limitations of thermal ablation techniques. This review provides a description of the principle of IRE, combined with an overview of in vivo research performed to date in the liver, pancreas, kidney, and prostate.

Upper tract urothelial carcinoma (UTUC) is a rare condition and recommendations based on a high level of evidence for diagnosis, treatment and follow-up monitoring are lacking. Current decision-making is often based on evidence from trials investigating urothelial carcinoma of the lower tract. Radical nephroureterectomy has been the standard of care for UTUC but kidney-sparing treatment using endoscopic approaches has been established for a select patient group with low-grade and low-stage disease. Optimal treatment choice requires correct tumour characterization. According to available recommendations, diagnostic work-up of UTUC includes evaluation by CT urography or MRI urography, cystoscopy and urine cytology. Ureterorenoscopy and lesion biopsy are grade C recommendations in patients with suspected UTUC. When kidney-sparing treatment is planned, ureterorenoscopy and biopsy should be considered and are the procedures of choice in most cases. These diagnostics have limitations and their accuracy varies in defining tumour characteristics and predicting grade and stage. Urinary tests have higher sensitivity than cytology for detection of lower tract urothelial carcinoma but evidence of their benefit in UTUCs is lacking. New optical and image enhancement techniques are being developed to facilitate real-time diagnostics with increased accuracy. A new diagnostic algorithm for patients with suspected UTUC that integrates the diagnosis, treatment and clinical risk stratification is required.

No abstract

NBI, SPIES, and PDD aim at improving visualization of UUT-UC through contrast enhancement. OCT and CLE aim at providing real-time predictions of histopathological diagnosis. For all techniques, more research has to be conducted before these techniques can be implemented in the routine management of UUT-UC. All techniques might be of value in specific clinical scenarios and allow for integration, for example, OCT with NBI, and could therefore improve tumor detection and staging and help in selecting the optimal treatment for the individual patient.

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

This report describes optical coherence tomography as a real-time, intraoperatively diagnostic modality in the diagnostic evaluation of upper tract urothelial carcinoma. We confirmed the ability of optical coherence tomography to visualize, grade and stage urothelial carcinoma in the upper urinary tract.

No abstract

Abstract. The objective of this study is to demonstrate the feasibility of needle-based optical coherence tomography (OCT) and functional analysis of OCT data along the full pullback trajectory of the OCT measurement in the prostate, correlated with pathology. OCT images were recorded using a commercially available C7-XR™ OCT Intravascular Imaging System interfaced to a C7 Dragonfly™ intravascular 0.9-mm-diameter imaging probe. A computer program was constructed for automated image attenuation analysis. First, calibration of the OCT system for both the point spread function and the system roll-off was achieved by measurement of the OCT signal attenuation from an extremely weakly scattering medium (Intralipid® 0.0005 volume%). Second, the data were arranged in 31 radial wedges (pie slices) per circular segments consisting of 16 A-scans per wedge and 5 axial B-scans, resulting in an average A-scan per wedge. Third, the decay of the OCT signal is analyzed over 50 pixels (500 μm) in depth, starting from the first found maximum data point. Fourth, for visualization, the data were grouped with a corresponding color representing a specific μ oct range according to their attenuation coefficient. Finally, the analyses were compared to histopathology. To ensure that each single use sterile imaging probe is comparable to the measurements of the other imaging probes, the probe-to-probe variations were analyzed by measuring attenuation coefficients of 0.03, 6.5, 11.4, 17, and 22.7 volume% Intralipid®. Experiments were repeated five times per probe for four probes. Inter-and intraprobe variation in the measured attenuation of Intralipid samples with scattering properties similar to that of the prostate was <8% of the mean values. Mean attenuation coefficients in the prostate were 3.8 mmfor parts of the tissue that were classified as benign (SD: 0.8 mm −1 , minimum: 2.2 mm −1 , maximum: 8.9 mm −1 ) and 4.1 mm −1 for parts of tissue that were classified as malignant (SD: 1.2 mm −1 , minimum: 2.5 mm −1 , maximum: 9.0 mm −1 ). In benign areas, the tissue looked homogeneous, whereas in malignant areas, small glandular structures were seen. However, not all areas in which a high attenuation coefficient became apparent corresponded to areas of prostate cancer. This paper describes the first in-tissue needle-based OCT imaging and three-dimensional optical attenuation analysis of prostate tissue that indicates a correlation with pathology. Fully automated attenuation coefficient analysis was performed at 1300 nm over the full pullback. Correlation with pathology was achieved by coregistration of three-dimensional (3-D) OCT attenuation maps with 3-D pathology of the prostate. This may contribute to the current challenge of prostate imaging and the rising interest in focal therapy for reduction of side effects occurring with current therapies.