Image-guided thermal ablation of central renal tumors with retrograde cold pyeloperfusion technique: a monocentric experience

Protection from injury to organs adjacent to a renal tumor during Imaging-guided thermal ablation with hydrodissection and pyeloperfusion

PURPOSE

The treatment of renal tumors is dictated by the results acquired from renal imaging, which play a crucial role in determining the appropriate strategy and surgical plan. Radiofrequency ablation, microwave ablation, and cryoablation are established percutaneous thermal ablation procedures that have widespread recognition. The objective of this scholarly article is to present a comprehensive summary of the application of the primary thermal protection strategies of the structures adjacent to renal tumors, in particular the effectiveness in terms of safety of hydrodissection and pyeloperfusion, in the context of percutaneous thermal ablation for renal tumors.

METHODS

A literature search was conducted in PubMed in April 2023 using the keywords "hydrodissection", "hydrodisplacement", "renal", "kidney", "percutaneous ablation", "cryoablation", "microwave", "radiofrequency", and "pyeloperfusion". No language restriction was applied.

RESULTS

Our study yielded a total of 676 cases describing the use of either hydrodissection or pyeloperfusion in conjunction with percutaneous thermal ablation. The fluids employed for displacing the neighboring structures encompassed saline solution, a mixture of saline solution and iodinated contrast, 5% dextrose in water, iodinated contrast in dextrose solution, lactated singer solution, and iodinated contrast.

CONCLUSIONS

By using these procedures effectively, a greater number of ablations could be performed on anterior or lower polar renal tumors, sometimes excluded from these treatments due to the high risk of causing damage to adjacent anatomical structures.

An Updated Systematic Review and Meta-Analysis on the Technical, Oncologic, and Safety Outcomes of Microwave Ablation in Patients with Renal Cell Carcinoma

Introduction: Percutaneous microwave ablation (MWA) has emerged as a new energy modality for percutaneous renal tumor ablation with potential advantages over radiofrequency and cryoablation. The goal of our study was to determine MWA outcomes for suspicious renal masses, with a subset analysis for biopsy-proven renal cell carcinoma (RCC) and larger (T1b) tumors. Methods: Studies reporting outcomes of MWA for RCC were identified. Random-effects models with inverse-variance weighting were used to pool outcomes, including technical success rate (TSR), technical efficacy rate (TER), local recurrence rate (LRR), cancer-specific survival rate (CSSR), overall survival rate (OSR), and complications. Results: Among 914 studies captured, 27 studies with 1584 patients (1683 malignant renal tumors) were included. The pooled TSR and TER were 99.6% (95% confidence interval [CI], 98.0%-100%) and 96.2% (95% CI, 93.8%-98.2%). The pooled LRR was 3.2% (95% CI, 1.9%-4.7%). At 1, 3, and 5 years, the pooled CSSRs were 100% (95% CI, 99.4%-100%), 100% (95% CI, 98.4%-100%), and 97.7% (95% CI, 94.5%-99.7%), while pooled OSRs were 99.0% (95% CI, 97.5%-99.9%), 96.0% (95% CI, 93.1%-98.3%), and 88.1% (95% CI, 80.3%-94.2%). The pooled minor and major complication rates were 10.3% (95% CI, 7.1%-13.9%) and 1.0% (95% CI, 0.3%-2.1%). In 204 patients with 208 T1b tumors, the pooled TSR and TER were 100% (95% CI, 96.6%-100%) and 85.2% (95% CI, 71.0%-95.8%). The pooled LRR was 4.2% (95% CI, 0.9%-8.9%). At 1, 3, and 5 years, the pooled CSSRs were 98.2% (95% CI, 88.7%-100%), 97.2% (95% CI, 78.5%-100%), and 98.1% (95% CI, 72.3%-100%). At 1 and 3 years, the pooled OSRs were 94.3% (95% CI, 85.7%-99.6%) and 89.3% (95% CI, 68.7%-100%). The pooled minor and major complication rates were 14.8% (95% CI, 7.4%-23.8%) and 2.6% (95% CI, 0%-7.8%). Conclusions: MWA demonstrated favorable short- to intermediate-term oncologic outcomes with low complication rates, including in the T1b subset, with moderate quality of data and heterogeneity of assessed outcomes. This supports MWA as a safe and effective treatment for RCC and a potential viable option for larger tumors.

Image-Guided Ablations in Patients with Recurrent Renal Cell Carcinoma

Renal cell carcinoma (RCC) is one of the most frequently diagnosed tumors and a leading cause of death. The high risk of local recurrence and distant metastases represent a significant clinical issue. Different image-guided ablation techniques can be applied for their treatment as an alternative to surgery, radiotherapy or systemic treatments. A retrospective analysis was conducted at our institution, including a total number of 34 RCC patients and 44 recurrent RCC tumors in different locations (kidney, lung, adrenal gland, liver, pancreas, pararenal and other) using microwave ablation, radiofrequency ablation, cryoablation and laser ablation. The estimated time to local and distant tumor progression after treatment were 22.53 ± 5.61 months and 24.23 ± 4.47 months, respectively. Systemic treatment was initiated in 10/34 (29%) treated patients with a mean time-to-systemic-therapy of 40.92 ± 23.98 months. Primary technical success was achieved in all cases and patients while the primary efficacy rate was achieved in 43/44 (98%) cases and 33/34 (97%) patients, respectively, with a secondary technical success and efficacy rate of 100%. At a mean follow-up of 57.52 months ± 27.86 months, local tumor progression occurred in 3/44 (7%) cases and distant progression in 25/34 (74%) patients. No significant complications occurred. Image-guided ablations can play a role in helping to better control recurrent disease, avoiding or delaying the administration of systemic therapies and their significant adverse effects.

Role of Fusion Imaging in Image-Guided Thermal Ablations

Thermal ablation (TA) procedures are effective treatments for several kinds of cancers. In the recent years, several medical imaging advancements have improved the use of image-guided TA. Imaging technique plays a pivotal role in improving the ablation success, maximizing pre-procedure planning efficacy, intraprocedural targeting, post-procedure monitoring and assessing the achieved result. Fusion imaging (FI) techniques allow for information integration of different imaging modalities, improving all the ablation procedure steps. FI concedes exploitation of all imaging modalities’ strengths concurrently, eliminating or minimizing every single modality’s weaknesses. Our work aims to give an overview of FI, explain and analyze FI technical aspects and its clinical applications in ablation therapy and interventional oncology.