Predicting renal functional outcomes after surgery for renal cortical tumours: a multifactorial analysis

OBJECTIVE To examine the functional outcomes after radical (RN) and partial nephrectomy (PN) stratified by variables before and after surgery, using estimated glomerular filtration rate (eGFR), as nephrectomy is the standard treatment for localized renal tumours, but the risk of developing chronic kidney disease (CKD) increases after surgery. PATIENTS AND METHODS We retrospectively analysed patients treated with PN or RN for renal cancer at one institution from 1988 to 2008. Chronic renal function before and after surgery was measured using the eGFR computed using the Modification of Diet in Renal Disease equation. Four outcomes were measured: (i) presence of new-onset renal insufficiency (eGFR < 60 mL/min/1.73m2); (ii) the percentage change in eGFR; (iii) the change in CKD stage; and (iv) the presence of CKD upstaging. Regression models were used to determine the effect of surgical procedure (RN vs PN), access technique (open vs laparoscopic) and several preoperative characteristics on functional outcomes. RESULTS In all, 276 patients met the inclusion criteria (174 RN and 102 PN) of whom 209 had a preoperative eGFR of > 60 mL/min/1.73m2. After >= 3 months from surgery, 108/209 (52%) patients developed new-onset eGFR of < 60 mL/min/1.73m2. On multivariate analysis, preoperative CKD stage (P < 0.001) and procedure (P = 0.001) were both independent predictors of all four functional outcomes measured. Also, hypertension was an independent predictor of CKD upstaging (P = 0.02). Surgical access technique was not an independent predictor of any of the renal functional outcomes measured. CONCLUSION Patients undergoing renal surgery have a high rate of new-onset CKD afterward. After controlling for preoperative risk factors, patients undergoing RN are at greater risk of a decline in renal function. However, surgical access technique was not a significant predictor for renal impairment.