Prediction of significant estimated glomerular filtration rate decline after renal unit removal to aid in the clinical choice between radical and partial nephrectomy in patients with a renal mass and normal renal function.

OBJECTIVES: To develop a clinically applicable predictive model to quantitate the risk of estimated glomerular filtration rate (eGFR) decline to ≤45 mL/min/1.73 m2 after radical nephrectomy (RN) to better inform decisions between RN and partial nephrectomy (PN). PATIENTS AND METHODS: Our prospectively maintained kidney cancer registry was reviewed for patients with a preoperative eGFR >60 mL/min/1.73 m2 who underwent RN for a localized renal mass. New baseline renal function was indexed. We used multivariable logistic regression to develop a predictive nomogram and evaluated it using receiver-operating characteristic (ROC) analysis. Decision-curve analysis was used to assess the net clinical benefit.
RESULTS: A total of 668 patients met the inclusion criteria, of whom 183 (27%) experienced a decline in eGFR to ≤45 mL/min/1.73 m2 . On multivariable analysis, increasing age (P = 0.001), female gender (P < 0.001), and increasing preoperative creatinine level (P < 0.001) were associated with functional decline. We constructed a predictive nomogram that included these variables in addition to comorbidities with a known association with kidney disease, but found that a simplified model excluding comorbidities was equally robust (cross-validated area under the ROC curve was 0.78). Decision-curve analysis showed the net clinical benefit at probabilities >~11%.
CONCLUSIONS: The decision to perform RN vs PN is multifaceted. We have provided a simple quantitative tool to help identify patients at risk of a postoperative eGFR of ≤45 mL/min/1.73 m2 , who may be stronger candidates for nephron preservation.