Is There a Role for Combination, Single-Session Selective Transarterial Embolization and Microwave Ablation for Large Renal Masses?

Changes in Microwave Ablation Zone Dimensions after Transarterial Embolization in an Ex Vivo Human Kidney Perfusion Model

PURPOSE

To utilize a novel ex vivo perfused human renal model and quantify microwave ablation (MWA) size differences in renal tissue when combining MWA with transarterial embolization (TAE).

MATERIALS AND METHODS

Human kidneys (n = 5) declined for transplantation were obtained and connected to a fluoroscopy-compatible ex vivo perfusion system. Two ablations-1 standard MWA and 1 TAE-MWA-were performed in each kidney for 2 minutes at 100 W using a MWA system (Solero Angiodynamics). MWA alone was performed in the upper pole. In the lower pole, MWA was performed after TAE with 40-90 μm radiopaque microspheres to achieve angiographic stasis. Ablation zones of coagulative necrosis were sectioned along the long axis and segmented for maximal short-axis diameter (SAD) and long-axis diameter (LAD) measurements.

RESULTS

A total of 10 ablations (5 MWAs and 5 TAE-MWAs) were performed in 5 human kidneys. TAE-MWA resulted in significantly increased SAD, LAD, volume, and sphericity compared with standard MWA ± SD, with mean measurements as follows (5 standard MWAs ± SD vs 5 TAE-MWAs ± SD, 2-tailed t-test): (a) SAD, 1.8 cm (SD ± 0.1) versus 2.5 cm (SD ± 0.1) (P < .001); (b) LAD, 2.9 cm (SD ± 0.3) versus 3.2 cm (SD ± 0.1) (P = .039); (c) volume, 5.0 mL (SD ± 0.5) versus 11.0 mL (SD ± 0.7) (P < .001); and (d) sphericity, 0.4 (SD ± 0.2) versus 0.6 (SD ± 0.1) (P = .049). Histology demonstrated no differences in TAE-MWA other than concentrated microspheres.

CONCLUSIONS

This ex vivo human kidney perfusion model confirmed that combined MWA-TAE significantly increased ablation size and spherical shape compared with MWA alone.

Effect of iodized oil embolization on temperature change during cryoablation for renal cell carcinoma

INTRODUCTION

We aimed to evaluate the effect of transcatheter arterial embolization (TAE) with iodized oil (Lipiodol) on temperature change during cryoablation (CA) for renal cell carcinoma (RCC).

MATERIAL AND METHODS

We retrospectively reviewed patients receiving CA for RCC from February 2020 to July 2021, including those who received Lipiodol TAE prior to CA (TAE group) and those who underwent only CA with comparable clinical and tumor characteristics (non-TAE group). Clinical data and tumor characteristics of both groups were recorded. The temperature readings of each cryoprobe at every 15 s and 'time to -100 °C' were compared between the groups.

RESULTS

A total of 17 patients with 18 RCCs were recruited (seven in the TAE group and 11 in the non-TAE group). The 'time to -100 °C' was significantly longer in the TAE group than in the non-TAE group (64.5 ± 24.3 s vs. 48.8 ± 9.7 s, p = 0.018). Positive correlation between 'time to -100 °C' and tumor maximal diameter, RENAL nephrometry and PADUA score were observed in the non-TAE group, while no corresponding correlation was found in the TAE group.

CONCLUSIONS

Pre-embolization with iodized oil influences the temporal temperature changes during cryoablation by disrupting the positive correlation between the time to reach the target temperature and tumor characteristics.

Percutaneous Ablation of T1b Renal Cell Carcinoma: An Overview

PURPOSE OF REVIEW

There is increasing incidence of renal cell carcinoma (RCC) with multiple treatment options currently available. The purpose of this review is to outline patient selection and technical approaches and present the current literature for percutaneous ablation of T1b (4.1-7 cm) RCC.

RECENT FINDINGS

An increasing number of retrospective studies and meta-analyses have evaluated the use of percutaneous ablation for T1b RCC. Overall, these studies tend to show that percutaneous ablation in this patient population is feasible. However, rates of major adverse events and local recurrence after percutaneous ablation for T1b RCC are both higher than when ablation is used for smaller tumors. As such, a multi-disciplinary, patient-centered approach is required. Due to the increasing literature in this area, the most recent National Comprehensive Cancer Network (NCCN) guidelines include percutaneous ablation as an option for non-surgical patients with T1b RCC.

Percutaneous treatment of renal tumours

Image-guided ablation is an accepted treatment option in the management of renal cell carcinoma. Percutaneous renal ablation offers the possibility of minimally invasive treatment while attempting to preserve renal function. Over the past several years there have been advances in tools and techniques that have improved procedure safety and patient outcomes. This article provides an updated comprehensive review of percutaneous ablation in the management of renal cell carcinoma.