Kidney function following nephrectomy: similitude and discrepancies between kidney cancer and living donation

Abstract

Objectives: The reported long-term safety of kidney donation is inconsistent with the impairment of kidney function observed following nephrectomy for renal cell cancer. We aimed to investigate if indication for nephrectomy (kidney cancer vs. living donation) was an independent risk factor for kidney function deterioration.

Materials and methods: Between 1985 and 2008, 124 patients with localized renal cell carcinoma who meet the criteria used for living donation, underwent radical nephrectomy (group 1) at our institution. Group 1 was retrospectively compared with 124 consecutive living donor nephrectomies (group 2) performed from 2004 to 2008. Kidney function evaluation was performed preoperatively and at 1, 2, 3, and 4 years postoperatively with calculation of estimated glomerular filtration rate through the Modification of Diet in Renal Disease (MDRD-eGFR) and the adjusted Cockroft and Gault (CG-eGFR) formula. Multivariate logistic regression included patients' characteristics and indication for nephrectomy as predictors of kidney function deterioration.

Results: Mean decrease in MDRD-eGFR was 30.4% and 32.4% in groups 1 and 2 (P = 0.30). Prevalence of chronic kidney disease (CKD), defined by MDRD-eGFR < 60 mL/min/m(2), varied from 42.3% to 71% in group 1 and from 41.6% to 56% in group 2 at different time points (P = 0.073). Prevalence of CKD at 4 years defined by MDRD-eGFR < 45 mL/min/m(2) was significantly increased in group 1 compared with group 2 (16.2% and 5.3%, P < 0.005, respectively). Linear regression analysis showed only baseline kidney function and patient age predicted a significant decrease in postoperative kidney function (P < 0.001 and P = 0.04).

Conclusions: Renal cell carcinoma is not an independent risk factor for kidney function impairment following nephrectomy. Selected kidney cancer patients with few morbidities face the same deterioration of meanly 30% of kidney function compared with living donors, but their lower baseline function results in an increased risk for CKD.