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SIR 2026

Traditional Poster

Interventional Oncology

Ablation

Session: Traditional Poster Presentations

558 - Comparing Local Recurrence After Microwave Ablation and Partial Nephrectomy for Biopsy Proven cT1a Renal Cell Carcinoma with at Least 3 Year Follow Up

Monday, April 13, 2026
12:10 PM - 1:10 PM ET
Purpose: Microwave ablation (MWA) is an ablation technology that has advantages compared to other thermal techniques, including decreased ablation time and heat sink effect. Management of small renal masses with ablation is becoming increasingly popular due to benefits such as the minimally invasive approach, same day discharge, and shorter recovery. {1} In this study, we compare local recurrence rates of biopsy-proven cT1a renal cell carcinoma (RCC) patients treated with CT-guided MWA vs partial nephrectomy (PN).

Materials and Methods: In this single-institution retrospective study, inclusion criteria consisted of patients with cT1a lesions from 10/2015-12/2022 managed surgically (n=200) or with MWA (n=272). Exclusion criteria were patients who underwent radical nephrectomy or with multifocal tumors, dialysis patients, prior surgical or ablative therapy, or less than 3 years of follow-up. Clinical, pathologic, radiologic, and oncologic data was obtained. The primary outcome was defined as radiologic evidence of local recurrence on imaging after treatment. Secondary outcomes were secondary technique effectiveness (successful re-ablation) and renal function.




Results: A total of 120 MWA patients and 73 PN patients met the above criteria for analysis. Patients who underwent MWA were older (69 vs 64 years, p< 0.001), had higher Charlson co-morbidity scores (5 vs 3, p < 0.001), had smaller tumors on pre-procedure imaging (2.1 vs 2.5, p=0.001), and worse renal function (serum creatinine 1.05 vs 0.91, p< 0.001). At 3 years, local recurrence rates of MWA and PN statistically similar (3.3% vs 2.7%, p=0.82). Of 4 MWA patients with local recurrence, all 4 were treated successfully with re-MWA resulting in a total secondary technique effectiveness of 100%. Post-procedurally, the differences in renal function were persistent within six and fifteen months with median creatinine of 1.15 vs 0.99 (p< 0.001) and 1.15 vs 1.01 (p=0.006), respectively.



Conclusion: Patients undergoing MWA were older with more co-morbidities and lower renal function, compared to those who received PN. In patients with cT1a renal masses, MWA demonstrates comparable clinical outcomes to PN, while additionally conferring the benefits of a minimally invasive procedure.