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Long-Term Outcome Data from 47 Treated Renal Malignancies with MRI-Guided and Monitored Laser Ablation: A Single Center Study

Login to Access Video or Poster Abstract: MP100-05
Sources of Funding: None

Introduction

Percutaneous ablation has become a viable treatment option for localized renal malignancy. MRI guidance has shown an added value for intraprocedural confirmation of complete ablation, potentially reducing the incidence of recurrence. The aim of this study is to report the long term local control data associated with in-bore MRI-guided laser ablation of renal malignancies.

Methods

34 patients (18M, 16F, age=29-88y) with 47 renal masses underwent biopsies followed by MRI-guided laser ablations. A laser fiber with 15mm diffusing tip encased in 5.5 F cooling catheter (Visualase, Texas, USA) was introduced into the target lesion. A test dose of diode laser energy (980nm, 30sec, 9W) was applied to verify location of ablation nidus. Subsequently, ablative energy dose was delivered (27W cycles of 90-240 sec) with treatment endpoint based realtime thermal monitoring of ablation. Fiber repositioning for additional ablation was conducted as needed.

Results

Biopsies showed 1 renal metastasis from lung cancer and 46 RCCs (23 clear, 11 papillary, 2 chromophobe, 7 oncocytic, 1 poorly differentiated, 2 not specified). Tumor sizes were 0.7-4.5 cm (17 upper, 10 lower, 19 midpole). 11 patients (30%) had a single kidney, 6 patients (18%) had prior partial nephrectomy, and 2 lesions were recurrent after cryoablation. Access to desired part of kidney was feasible in all cases. The flexible nature of laser fibers eliminated the complexity of handling bulky ablation probes. Short ablation cycles facilitated accurate temperature mapping. 9 small-moderate self-limited perinephric hematomas and 1 delayed abscess occurred. Otherwise, no complications were encountered. Median follow-up was 24 months (max = 56 months). No residual or recurrent neoplasms were identified.

Conclusions

Interactively guided renal ablations performed within an interventional MRI suite are safe and well-tolerated. Data indicate reliable local tumor control with 0% recurrence rate over extended follow-up durations. Efficacy is likely related to improved visualization of tumor margins and temperature sensitivity of MRI allowing refined ablation procedures tailored to tumor response rather than following standard pre-determined ablation parameters.

Funding

None

Authors
Sherif Nour
Kareem Elfatairy
Debra Weber
Melinda Lewis
Viraj Master
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