Introduction

Partial nephrectomy (PN) is considered a strong (imperative/relative) indication for patients with stage 3 chronic kidney disease [(CKD), estimated glomerular filtration rate (eGFR)<60 ml/min/1.73m2] and is considered elective for patients with higher GFR. Change in GFR (δGFR) is less for PN compared to radical nephrectomy (RN), and patients with stage 2 CKD (eGFR 60-89) may be at increased risk for postoperative renal decline to thresholds of increased risk. We compared renal function and survival outcomes in patients with baseline stage 2 CKD who underwent PN or RN.

Methods

International multicenter retrospective analysis of patients with baseline stage 2 CKD who underwent PN or RN from 1987-2015. Demographics, disease characteristics, survival and renal function outcomes were recorded. Patients were stratified into baseline Stage 2a CKD (GFR 75-89) and Stage 2b CKD (GFR 60-74.9) for analysis. Primary outcome was δGFR at last follow up. Secondary outcomes included occurrence of GFR<45, a risk factor for poor survival outcomes, and overall survival (OS). Cox proportional hazard regression, Kaplan Meier analysis, and multivariable (MV) regression for risk factors associated with outcomes was performed.

Results

1460 patients were analyzed (mean age 61.9 years, median follow up 46 months). 49.3% underwent PN/50.7% underwent RN, and 49.5% were Stage 2a CKD (n=723) while 50.5% were Stage 2b CKD (n=737). Mean δGFR was greater for RN than PN overall (-12.5 vs. -6.5, p<0.001), in stage 2a CKD (-12.9 vs. -10.0, p<0.001), and stage 2b CKD (-11.9 vs. -2.9, p<0.001). Cox proportional hazard regression for GFR<45 noted negative effect for RN overall (HR 1.78, p<0.001), in Stage 2a CKD (HR 1.88, p=0.019), and in Stage 2b CKD (HR 1.74, p=0.002). On MV regression for GFR<45, Stage 2b CKD (OR 1.70, p<0.001) and RN (OR 1.47, p=0.028) were independent risk factors. MV regression for OS was worse for RN overall (OR 2.93, p<0.001), in Stage 2a CKD (OR 3.12, p<0.001), and in 2b CKD (OR 2.77, p<0.001).

Conclusions

Patients with baseline Stage 2 CKD undergoing RN are at increased risk of GFR decline, including the threshold of GFR<45, and worsened OS. For patients with Stage 2 CKD, PN may be considered a relative indication and should be prioritized when appropriate.

Funding

Stephen Weissman Kidney Cancer Research Fund. NIH grants UL1TR000100 and UL1TR001442.