Irreversible electroporation, a new modality in Focal Therapy for prostate cancer.

The extensive use of prostate-specific antigen (PSA) testing and improved imaging technologies have resulted in an increased diagnosis of prostate cancer. Early diagnosis is often accompanied by an increased number of localized (i.e. unifocal or unilateral), small-volume and low-grade prostate cancers. Focal therapy is an emerging treatment option in prostate cancer, targeting individual cancer areas while sparing important functional and anatomical urological structures. Irreversible electroporation is an innovative treatment modality in focal therapy based on the process of cell membrane electroporation limiting damage to adjacent tissue and vital structures. The first phase I-II trials in humans have shown the safety of IRE for focal ablative therapy of prostate cancer and showed encouraging results considering functional preservation. Histological analysis after IRE showed fibrosis without glandular ducts and necrotic tissue with sharp demarcation between unaffected prostatic glandular tissue and the ablation zone. Short-term oncological results are promising; however more data on long-term oncological outcomes are necessary. New studies with IRE and other focal treatment modalities are initiated to explore opportunities for focal therapy in prostate cancer and to optimize current treatment protocols.

Follow-up after focal therapy in renal masses: an international multidisciplinary Delphi consensus project.

PURPOSE: To establish consensus on follow-up (FU) after focal therapy (FT) in renal masses. To formulate recommendations to aid in clinical practice and research. METHODS: Key topics and questions for consensus were identified from a systematic literature research. A Web-based questionnaire was distributed among participants selected based on their contribution to the literature and/or known expertise. Three rounds according to the Delphi method were performed online. Final discussion was conducted during the "8th International Symposium on Focal Therapy and Imaging in Prostate and Kidney Cancer" among an international multidisciplinary expert panel. RESULTS: Sixty-two participants completed all three rounds of the online questionnaire. The panel recommended a minimum follow-up of 5 years, preferably extended to 10 years. The first FU was recommended at 3 months, with at least two imaging studies in the first year. Imaging was recommended biannually during the second year and annually thereafter. The panel recommended FU by means of CT scan with slice thickness ≤3 mm (at least three phases with excretory phase if suspicion of collecting system involvement) or mpMRI. Annual checkup for pulmonary metastasis by CT thorax was advised. Outside study protocols, biopsy during follow-up should only be performed in case of suspicion of residual/persistent disease or radiological recurrence. CONCLUSIONS: The consensus led to clear FU recommendations after FT of renal masses supported by a multidisciplinary expert panel. In spite of the low level of evidence, these recommendations can guide clinicians and create uniformity in the follow-up practice and for clinical research purposes.

Histopathological Outcomes after Irreversible Electroporation for Prostate Cancer: Results of an Ablate and Resect Study.

PURPOSE: Irreversible electroporation is a tissue ablation modality that uses high voltage electric energy to induce an increase in cell membrane permeability. This causes destabilization of the existing cellular transmembrane potential leading to cell death, due to the inability to maintain cellular homeostasis. This phase I-II study was designed to evaluate the histopathological outcomes of irreversible electroporation to prostate and surrounding tissue in radical prostatectomy specimens. MATERIALS AND METHODS: Sixteen patients with prostate cancer underwent an irreversible electroporation ablation without curative intent, followed by radical prostatectomy scheduled 4 weeks later. For histopathological examination of the prostate, whole mounted tissue slices were examined by dedicated genitourinary pathologists. The borders of the ablation zone and residual tumor were outlined on the slides. RESULTS: The irreversible electroporation ablation zones were characterized as areas of fibrosis, necrosis and loss of epithelial tissue in terms of denudation in the glandular structures. The ablation zone was well demarcated, showing trenchant delineations between viable and nonviable tissue. The ablated tissue showed mild to moderate inflammation, with atrophic cells in 1 case. The area was surrounded by hemorrhage at the location of the electrodes. No skip lesions or viable tissue was seen in the ablation zone. Fibrinoid necrosis of the neurovascular bundle was observed in 13 patients and denudation of the urothelium of the prostatic urethra was seen in 9. CONCLUSIONS: Histopathological assessment of the prostate 4 weeks after irreversible electroporation ablation showed sharply demarcated fibrotic and necrotic tissue in the ablation zone. No viable tissue was observed in the irreversible electroporation ablation zone.

The role of imaging in the active surveillance of small renal masses.

Up to 66 % of renal cell carcinomas are detected as small renal masses before the presence of clinical symptoms. Small renal mass treatment has evolved from the exclusive use of radical nephrectomy to the use of nephron sparing procedures where possible. An increase in elderly and comorbid patients, together with the notion that just 20 % of small renal masses show high malignant potential, has prompted interest in active surveillance as a treatment option. Modern imaging techniques provide objective follow-up parameters, namely size, invasion of collecting system or perirenal fat and enhancement patterns, with minimal complication risks or patient discomfort. This review evaluates recent developments in the field of active surveillance for small renal masses. Special focus is placed on the role of imaging in the primary decision making and subsequent follow-up during active surveillance.