Poster Session 9: Oncology – Kidney, Other

Introduction: Irreversible electroporation (IRE) is a novel, non-thermal ablation procedure used for treating small renal masses (SMR), such as renal cell carcinomas (RCC).This prospective case series explores IRE's effectiveness and six-year outcomes in patients with difficult-to-treat RCC.We report tumor-free survival (TFS) and document complications and renal function changes.Methods: IRE was offered to patients with a biopsy-confirmed RCC in a solitary kidney, von Hippel Lindau syndrome, or a difficult-to-treat RCC that was deemed amenable only to radical nephrectomy for tumor control.Followup protocol at three, 12, 24, 36, 48, 60, and 72 months post-IRE included creatinine, eGFR, and gadolinium-enhanced MRI to monitor for residual or recurrent disease.Results: Twenty-seven biopsy-proven RCC were treated in 27 patients.The median followup time was 42 months (range 3-72).Post-IRE, six patients experienced immediate adverse events (AE): four transient hematuria (Clavien-Dindo grade [CD] 1), one hematoma requiring transfusion (CD 2), and one PE (CD 2).One patient received a ureteral stent for a delayed ureteral stricture (CD 3a).At three months, residual tumors were found in five patients, making a treatment success rate of 81.5%.Four patients were managed with salvage thermal ablation (three microwave [MWA], one radiofrequency) and one patient underwent laparoscopic nephrectomy (LN).Four patients with recurrent RCC (mean time of 21 months) were managed with surveillance, MWA, and LN.No patient developed metastasis.The six-year TFS rate was 79.3%, with no deaths due to RCC.The average eGFR decline at 12 and 72 months was nine and 6.3 mL/min/1.73m2, respectively.Conclusions: This study demonstrates that patients with difficult-to-treat RCCs can be treated with IRE safely and effectively.Immediate AE were limited to CD 2 and fully resolved.The procedure success rate and the six-year TFS rate suggest that IRE is a feasible option for patients with complex SRM.Larger and longer studies are needed to evaluate long-term oncologic and functional outcomes.