Renal Cancer Surgery in Patients without Preexisting Chronic Kidney Disease-Is There a Survival Benefit for Partial Nephrectomy?

Abstract

Retrospective studies suggest that partial nephrectomy provides improved survival compared to radical nephrectomy even when performed electively. However, selection bias may contribute. We evaluated factors associated with nonrenal cancer related mortality after partial and radical nephrectomy in patients with a preoperative glomerular filtration rate of 60 ml/minute/1.73 m2 or greater. We retrospectively evaluated the records of 3,133 patients with a preoperative glomerular filtration rate of 60 ml/minute/1.73 m2 or greater who underwent partial or radical nephrectomy. Nonrenal cancer related mortality was analyzed by the Kaplan-Meier test based on procedure and functional parameters, including the new baseline glomerular filtration rate. We used the Cox proportional hazards model to assess factors associated with nonrenal cancer related mortality among patients with a new baseline rate of 45 ml/minute/1.73 m2 or greater. Overall median age was 59 years and the median preoperative glomerular filtration rate was 85 ml/minute/1.73 m2. The new baseline glomerular filtration rate was 80 and 63 ml/minute/1.73 m2 and 10-year nonrenal cancer related mortality was 11.3% and 17.7% after partial and radical nephrectomy, respectively (each p <0.001). Median followup was 9.3 years. Nonrenal cancer related mortality was similar in all patients with a new baseline glomerular filtration rate of 45 ml/minute/1.73 m2 or greater (p = 0.26). However, it increased 50% or more in the 290 patients with a new baseline below this level (p = 0.001). In patients with a new baseline greater than 45 ml/minute/1.73 m2 10-year nonrenal cancer related mortality was still substantially improved after partial nephrectomy (10.6% vs 16.3%, p <0.001). In this population age, gender and partial vs radical nephrectomy were associated with nonrenal cancer related mortality on multivariable analysis (all p ≤0.001). In contrast, the increased new baseline glomerular filtration rate, as seen for partial nephrectomy, was not associated with reduced nonrenal cancer related mortality. In patients with a glomerular filtration rate of 60 ml/minute/1.73 m2 or greater who undergo partial or radical nephrectomy our data suggest that treatment should achieve a new baseline of 45 ml/minute/1.73 m2 or greater if feasible. Partial nephrectomy should be prioritized if needed to accomplish this. In patients with a new baseline rate of 45 ml/minute/1.73 m2 or greater partial nephrectomy was associated with improved survival. However, the functional dividend, namely the increased new baseline rate, failed to correlate, suggesting that selection bias may also impact outcomes.