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.