To investigate renal functional change 6 months after robot-assisted partial nephrectomy (RAPN) and percutaneous cryoablation (PCA) in clinical stage T1 (cT1) renal cell carcinoma (RCC) and evaluate the relationship between baseline renal function and 6-month renal functional outcome.

The treatment options for individual patients were discussed in multidisciplinary team conferences with the participation of pathologists, radiologists, oncologists, and urologists. When NST was considered suitable, the final treatment decision was based on tumor characteristics, age, health status, renal function, and patient preference, following the principle of shared decision making.

Patients with cT1 RCC treated with RAPN or CT-guided PCA between June 2019 and January 2021 were prospectively and consecutively enrolled. Renal function was evaluated by estimated glomerular filtration rate (eGFR) using CKD-EPI equation, Tc-99m diethylenetriamine-pentaacetate (DTPA) plasma clearance, Tc-99m mercaptoacetyltriglycine (MAG3) renography, CKD stage based on eGFR, and renal volume at baseline and 6 months after treatment.

Fifty-six patients were included (18 RAPN, 38 PCA) with a median age of 66.5 years (interquartile range (IQR): 56.5-74.0). We found a significantly higher age (68.5 years; p=0.019) and Charlson comorbidity index (3.0; p=0.007) in PCA patients. The median tumor size was 3.3 cm (IQR: 2.5-3.9), and tumor characteristics did not differ significantly between RAPN and PCA.

For RAPN and cryoablation the change in renal function was: median p-creatinine +16.4%; p=0.007 and +11.5%; p <0.001, median eGFR -8.7%; p=0.008 and +2.8%; p<0.001, median DTPA-GFR -0.6%; p=0.002 and -1.4%; p=0.006, respectively. Total renal volume decreased significantly after PCA (-18.2 cm³; p=0.001), but not after RAPN. Baseline CKD stage IIIb-IV was predictive of a greater reduction in renal volume (-31.8 cm³;...

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This study found a small, similar decrease in renal function 6 months after RAPN or PCA. Patients with CKD IIIb-IV showed a greater decline in renal volume than patients with normal baseline renal function.