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Purpose: Ablation plays a growing role in the treatment of small renal masses (SRMs) due to its nephron sparing properties and low invasiveness. Irreversible electroporation (IRE) has the potential, although still experimental, to overcome current limitations of thermal ablation. No prospective imaging studies exist of the ablation zone in the follow up after renal IRE in humans. Objectives are to assess computed tomography (CT) and magnetic resonance imaging (MRI) on the ablation zone volume (AZV), enhancement and imaging characteristics after renal IRE.Methods: Prospective phase 2 study of IRE in nine patients with ten SRMs. MRI imaging was performed pre-IRE, 1 week, 3 months, 6 months and 12 months after IRE. CT was performed pre-IRE, perioperatively (direct after ablation), 3 months, 6 months and 12 months after IRE. AZVs were assessed by two independent observers. Observer variation was analyzed. Evolution of AZVs, and relation between the needle configuration volume (NCV; planned AZV) and CT- and MRI volumes were evaluated.Results: Eight SRMs were clear cell renal cell carcinomas, one SRM was a papillary renal cell carcinoma and one patient had a non-diagnostic biopsy. On CT, median AZV increased perioperatively until 3 months post-IRE (respectively, 16.8 cm3 and 6.2 cm3) compared to the NCV (4.8 cm3). On MRI, median AZV increased 1-week post-IRE until 3 months post-IRE (respectively, 14.5 cm3 and 4.6 cm3) compared to the NCV (4.8 cm3). At 6 months the AZV starts decreasing (CT 4.8 cm3; MRI 3.0 cm3), continuing at 12 months (CT 4.2 cm3, MRI 1.1 cm3). Strong correlation was demonstrated between the planning and the post-treatment volumes. Inter-observer agreement between observers was excellent (CT 95% CI 0.82-0.95, MRI 95% CI 0.86-0.96). All SRMs appeared non-enhanced immediately after ablation, except for one residual tumour. Subtraction images confirmed non-enhancement on MRI in unclear enhancement cases (3/9). Directly after IRE, gas bubbles, perinephric stranding and edema were observed in all cases.Conclusion: The AZV increases immediately on CT until 3 months after IRE. On MRI, the AZV increases at 1 week until 3 months post-IRE. At 6 months the AZV starts decreasing until 12 months post-IRE on both CT and MRI. Enhancement was absent post-IRE, except for one residual tumour. Gas bubbles, perinephric stranding and edema are normal findings directly post-IRE. [ABSTRACT FROM AUTHOR]

Purpose: Clinical outcomes prognostic markers are awaited in clear-cell renal carcinoma (ccRCC) to improve patient-tailored management and to assess six different markers' influence on clinical outcomes from ccRCC specimen and their incremental value combined with TNM staging. Materials and methods: This is a retrospective, multicenter study. One hundred and forty-three patients with pT1b-pT3N0M0 ccRCC were included. Pathology specimens from surgeries were centrally reviewed, mounted on a tissue micro-array and stained with six markers: CAIX, c-MYC, Ki67, p53, vimentin and PTEN. Images were captured through an Ultra Fast Scanner. Tumor expression was measured with Image Pro Plus. Cytoplasmic markers (PTEN, CAIX, vimentin, c-MYC) were expressed as surface percentage of expression. Nuclear markers (Ki67, p53) were expressed as number of cells/mm. Clinical data and markers expression were compared with clinical outcomes. Each variable was included in the Cox proportional multivariate analyses if p < 0.10 on univariate analyses. Discrimination of the new marker was calculated with Harrell's concordance index. Results: At median follow-up of 63 months (IQR 35.0-91.8), on multivariate analysis, CAIX under-expression and vimentin over-expression were associated with worse survival (recurrence, specific and overall survival). A categorical marker CAIX-/Vimentin+ with cutoff points for CAIX and vimentin of 30 and 50 %, respectively, was designed. The new CAIX-/Vimentin+ marker presented a good concordance and comparable calibration to the reference model. Limitations are the retrospective design, the need for external validation and the large study period. Conclusion: Using an automated technique of measurement, CAIX and vimentin are independent predictors of clinical outcomes in ccRCC. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

• To discuss the use of renal mass biopsy (RMB) for small renal masses (SRMs), formulate technical aspects, outline potential pitfalls and provide recommendations for the practicing clinician. • The meeting was conducted as an informal consensus process and no scoring system was used to measure the levels of agreement on the different topics. • A moderated general discussion was used as the basis for consensus and arising issues were resolved at this point. • A consensus was established and lack of agreement to topics or specific items was noted at this point. • Recommended biopsy technique: at least two cores, sampling different tumour regions with ultrasonography being the preferred method of image guidance. • Pathological interpretation: 'non-diagnostic samples' should refer to insufficient material, inconclusive and normal renal parenchyma. For non-diagnostic samples, a repeat biopsy is recommended. Fine-needle aspiration may provide additional information but cannot substitute for core biopsy. • Indications for RMB: biopsy is recommended in most cases except in patients with imaging or clinical characteristics indicative of pathology (syndromes, imaging characteristics) and cases whereby conservative management is not contemplated. RMB is recommended for active surveillance but not for watchful-waiting candidates. • We report the results of an international consensus meeting on the use of RMB for SRMs, defining the technique, pathological interpretation and indications. [ABSTRACT FROM AUTHOR]

AbstractAim:To evaluate the diagnostic feasibility and reproducibility of immediate postcryoablation biopsies of small renal masses.Materials and Methods:Between December 2006 and July 2007, 21 intraoperative pre- and postcryoablation (18-gauge core) biopsies of renal masses were obtained. Evaluation of the biopsies by the institutional uropathologist was followed by a blind assessment by two other uropathologists. Tumor subtype and Fuhrman grade were determined by the three pathologists, while biopsy timing (before or after cryoablation) was only assessed by the two blinded pathologists. The diagnostic yield of the pre- and postcryoablation biopsies and interobserver agreement were calculated.Results:The mean size of the 21 cryoablated tumors was 2.8 cm. No significant bleeding occurred after any biopsy. Of the precryoablation biopsies 75–81% was correctly labeled as precryo, and 48% of the postcryoablation biopsies as postcryo. The diagnostic yield of the three pathologists for precryo biopsies ranged between 67% and 71%, and for postcryo biopsies between 48% and 71% (not statistically different). When combining both types of biopsies, the overall diagnostic yield was 81% for all pathologists. The interobserver agreement was “almost perfect” (kappa = 0.902) for precryo biopsies and “substantial” (kappa = 0.514) for postcryo biopsies.Conclusion:This study shows that it is feasible to obtain histopathological diagnoses from postcryoablation biopsies with a diagnostic yield and interobserver agreement similar to precryoablation biopsies. [ABSTRACT FROM AUTHOR]