Efficacy and safety of microwave ablation in solitary kidney patients with T1a small renal masses

Objectives: To assess the safety and efficacy of using microwave ablation (MWA) to treat solitary kidney (SK) patients with T1a renal cell carcinoma (RCC).

Methods: Retrospective analysis of a prospectively maintained database identified patients with T1a RCC with either congenital or acquired SK. Estimated glomerular filtration rate (eGFR) was calculated from serum creatinine before MWA and after at 6 and 12 months post-procedure. The local recurrence-free survival (LRFS), metastatic-recurrence free survival (MRFS), cancer-specific survival, and overall survival were analyzed with the Kaplan-Meier method.

Results: A total of 26 patients met inclusion criteria, including 3 congenital and 23 acquired SK patients. eGFR was lower at both 6 and 12 months post-procedure compared to pre-procedure, with the congenital SK group having a more pronounced reduction in eGFR at both post-procedure timepoints. Median follow-up time was 28.6 months (IQR 12.4-55.4). Four patients (15.4%) experienced local recurrence. For LRFS, mean survival time was 69.4 months. There were 5 patients (19.2%) that experienced metastatic recurrence, with median and mean survival time at 101.1 and 82.0 months, respectively. The mean time for RCC-specific survival was 94.7 months, while median and mean time for overall survival was 43.1 and 61.7 months, respectively.

Conclusion: With a moderate reduction in renal function and a comparable rate of local recurrence compared to prior literature, this work demonstrates that MWA remains a viable alternative to more invasive techniques, particularly for high-risk SK patients with RCC. Our work highlights the need for further research on effectiveness of MWA in cancer control and preservation of renal function in larger cohorts of SK patients over extended follow-up times.