Kidney function decline in cT1a patients treated with Microwave Ablation versus Partial Nephrectomy.

Area of Science:

• Nephrology
• Urology
• Oncology

Background:

• Microwave ablation (MWA) is an emerging treatment for small renal masses (SRM), with oncological outcomes comparable to partial nephrectomy (PN).
• Further research is needed to understand the comparative impact of MWA and PN on kidney function decline in patients with clinical T1a (cT1a) SRM.

Purpose of the Study:

• To compare the progression of kidney function decline in patients with cT1a SRM treated with either MWA or PN.
• To analyze differences in estimated glomerular filtration rate (eGFR) changes, chronic kidney disease (CKD) upstaging, and composite endpoints between the two treatment groups.

Main Methods:

• Prospective data from 2015-2021 were analyzed, with kidney function data collected through 2024 from a single institution.
• Kidney function decline was assessed by a 30% drop in eGFR, CKD upstaging, and a composite endpoint, using Cox proportional hazards models.

Main Results:

• The study included 97 MWA and 49 PN patients. MWA patients were older with lower baseline eGFR and higher pre-treatment CKD rates.
• Univariate analysis showed no significant association between treatment modality and kidney function decline endpoints.
• After adjusting for patient factors, only baseline eGFR remained significantly associated with kidney function decline.

Conclusions:

• No statistically significant difference in kidney function decline was observed between PN and MWA for cT1a SRM.
• Adjusting for patient characteristics attenuated the initial observed higher hazard for MWA, highlighting the importance of baseline factors.