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Sources of Funding: None

Introduction

Renal functional outcomes are an important consideration when deciding among treatment options for a renal mass. However, there are conflicting data on renal functional outcomes when comparing partial nephrectomy (PN) and percutaneous cryoablation (CA). We therefore compared the changes in renal function between PN and CA patients with a solitary renal mass.

Methods

We retrospectively reviewed the Mayo Clinic nephrectomy and ablation registries to identify all patients who underwent PN or CA for a solitary renal mass between 2003-2013. Estimated glomerular filtration rates (eGFR) were calculated at baseline, prior to discharge, and at 3 months follow-up using the CKD-EPI equation and are reported as the percent change from baseline. Multivariable linear regression was used to compare the change in renal function between groups controlling for age, tumor size, and baseline eGFR. Subgroup analyses were performed in patients with baseline stage 3 or 4 chronic kidney disease (CKD) and those with a solitary kidney.

Results

There were 1650 PN and 481 CA identified, including 370 (22%) PN and 227 (47%) CA with stage 3 or 4 CKD at baseline and 91 (6%) PN and 69 (14%) CA with a solitary kidney. Overall, PN patients were younger (mean 59 vs 69 years, p<0.001), had a higher baseline eGFR (74.6 vs 62.7 ml/min/1.73m2, p<0.001), and had larger tumors (mean 3.5 vs 3.1 cm, p=0.001) compared to CA patients. On multivariable analyses, mean changes in eGFR from baseline at discharge and at 3 months follow-up for PN vs CA were -0.9% vs -5.9% (p<0.001) and -1.8 vs -7.0% (p<0.001), respectively. Similar results were found in the subgroup of patients with baseline stage 3 or 4 CKD at both discharge (4.2 vs -4.1%, p<0.001) and at 3 months follow-up (1.7 vs -5.2%, p<0.001), respectively. Among patients with a solitary kidney, no significant difference in the change in eGFR was found between PN and CA at either discharge (-13.2% vs -9.4%, p=0.27) or 3 months follow-up (-8.6 vs -12.6%, p=0.19).

Conclusions

Neither PN or CA cause clinically significant changes in renal function, including among patients with pre-existing renal dysfunction or a solitary kidney. While we observed a greater decline in renal function when CA was compared with PN, this difference was not significant in the subset of patients with a solitary kidney.

Funding

None