Why we should not routinely apply irreversible electroporation as an alternative curative treatment modality for localized prostate cancer at this stage

MRI-TRUS fusion for electrode positioning during irreversible electroporation for treatment of prostate cancer

We aimed to introduce an approach for image-guided positioning of electrodes for irreversible electroporation (IRE) in patients with prostate cancer using a magnetic resonance imaging-transrectal ultrasonography (MRI-TRUS) fusion technique. In 10 consecutive patients with biopsy-proven Gleason score ≤3+4 prostate cancer, 19 G electrodes were inserted into the prostate using a transperineal access. Magnetic resonance images of the prostate acquired before IRE were fused with transrectal ultrasound images acquired during IRE. The position of the ultrasound probe was tracked via a sensor and corresponding magnetic resonance images were calculated in real-time. While MRI allowed delineation of the target volume, the position of the electrodes could be visualized on ultrasound images; the distance between individual electrode pairs was measured. Based on these measurements the software installed on the IRE unit was able to calculate the voltage necessary to generate the electric field for ablation. Using contrast-enhanced ultrasound, changes in perfusion within the ablation zone after IRE were documented. This technique allowed positioning of the electrodes around the target volume under image guidance in all patients treated with IRE. The target lesion and a safety margin were covered within the estimated ablation zone. MRI-TRUS guidance for IRE combines the advantages of good visualization of the target lesion on MRI with the ability of ultrasound to acquire imaging in real-time with a mobile device.

Salvage Therapy Options for Local Prostate Cancer Recurrence After Primary Radiotherapy: a Literature Review

PURPOSE OF REVIEW

While recurrence after primary treatment of prostate cancer (PCa) is not uncommon, there is currently no consensus on the most appropriate management after radiation treatment failure. This article seeks to explore the currently utilized modalities for salvage treatment for radiorecurrent PCa. We focused our review on the oncologic outcomes and reported toxicity rates in the latest studies examining salvage radical prostatectomy (SRP), salvage cryotherapy (SCT), salvage high-intensity focused ultrasound (HIFU) and re-irradiation.

RECENT FINDINGS

There does not appear to be any significant difference in overall survival for more invasive salvage radical prostatectomy compared to the minimally invasive salvage approaches. Additionally, there seems to be a trend towards lower morbidity rates associated with minimally invasive and focal salvage treatment. We are encouraged by the results presented in this review and find that there is clearly a role for emerging minimally invasive and focal therapies as durable options for salvage treatment in patients with radiorecurrent PCa.

Focal Therapy in Primary Localised Prostate Cancer: The European Association of Urology Position in 2018

Radical treatment of localised prostate cancer is recognised to be an unnecessary intervention or overtreatment in many men. Consequently, there has been a rapid uptake in the use of focal ablative therapies. However, there are several biological and practical concerns about such approaches as they have yet to be proved as robust treatment options. In particular, the multifocal nature of prostate cancer argues against unifocal treatment, while limitations in imaging can preclude the accurate identification of the number, location, and extent of prostate cancer foci. To date, a number of ablative options have reported results on mainly low-risk disease. Most series are relatively immature, with a lack of consistent follow-up, and the morbidity of retreatment is often not considered. The authors consider focal therapy to be an investigational modality, and encourage prospective recording of outcomes and recruitment of suitable patients.

PATIENT SUMMARY

Focal therapy of prostate cancer is the targeted destruction of cancer within a specific part of the prostate gland, sparing the rest of the prostate and nearby tissue. This procedure could potentially reduce side effects when compared with established standard treatments, such as surgery or radiotherapy, which treat the entire prostate. Studies show that for most men with low-risk cancer, active surveillance is the preferred treatment option. However, the available data regarding all forms of focal therapy are still poor and inconclusive. Consequently, due to both the lack of clear results associated with focal therapy and the difficulties in detecting all cancerous areas of the prostate, focal therapy should be considered an investigational modality only.

[Indications and limits of ablative therapies in prostate cancer]

OBJECTIVE

To perform a state of the art about indications and limits of ablative therapies for localized prostate cancer.

METHODS

A review of the scientific literature was performed in Medline database (http://www.ncbi.nlm.nih.gov) and Embase (http://www.embase.com) using different associations of keywords. Publications obtained were selected based on methodology, language and relevance. After selection, 107 articles were analysed.

RESULTS

The objective to combine reduction of side effects and oncological control has induced recent development of several ablative therapies. Beyond this heterogeneity, some preferential indications appear: unilateral cancer of low risk (but with significant volume, excluding active surveillance) or intermediate risk (excluding majority of grade 4); treatment targeted the index lesion, by quarter or hemi-ablation, based on biopsy and mpMRI. In addition, indications must considered specific limits of each energy, such as gland volume and tumor localization.

CONCLUSION

Based on new imaging and biopsy, ablative therapies will probably increased its role in the future in management of localize prostate cancer. The multiple ongoing trials will certainly be helpful to better define their indications and limits.

Uncertainty Quantification in Irreversible Electroporation Simulations

One recent area of cancer research is irreversible electroporation (IRE). Irreversible electroporation is a minimally invasive procedure where needle electrodes are inserted into the body to ablate tumor cells with electricity. The aim of this paper is to investigate how uncertainty in tissue and tumor conductivity propagate into final ablation predictions used for treatment planning. Two dimensional simulations were performed for a circular tumor surrounded by healthy tissue, and electroporated from two monopolar electrodes. The conductivity values were treated as random variables whose distributions were taken from published literature on the average and standard deviation of liver tissue and liver tumors. Three different Monte Carlo setups were simulated each at three different voltages. Average and standard deviation data was reported for a multitude of electrical field properties experienced by the tumor. Plots showing the variability in the electrical field distribution throughout the tumor are also presented.