Prognostic significance of preoperative kidney volume for predicting renal function in renal cell carcinoma patients receiving a radical or partial nephrectomy

Abstract

Study Type - Prognosis (case series) Level of Evidence 4 What's known on the subject? and What does the study add? At present, many studies have been executed to identify predictors for chronic kidney disease or renal insufficiency after radical nephrectomy or partial nephrectomy. We examined whether preoperative kidney volume is a predictor for renal function after radical or partial nephrectomies in RCC patients. To our knowledge, this is the first study to report on the relationship between preoperative kidney volume and changes in renal function in RCC patients who underwent radical nephrectomy or partial nephrectomy performed by one surgeon.

Objective: To investigate whether preoperative kidney volume is a prognostic factor for predicting the postoperative glomerular filtration rate (GFR) in renal cell carcinoma (RCC) patients.

Patients and methods: We included 133 patients who underwent radical (n= 83) or partial (n= 50) nephrectomy for RCC. Kidney parenchymal volume was measured using personal computer-based software and GFR was estimated before and after surgery at 6 and 12 months. We evaluated the change in kidney volume after radical and partial nephrectomy and used regression analysis to identify predictors of lower post-surgical GFR at 12 months.

Results: The mean volume of the normal side kidney for the radical nephrectomy group increased from 142.4 mL to 166.0 mL (17.2%) and 171.5 mL (21.2%) after surgery at 6 and 12 months, respectively. In the partial nephrectomy group, the volume of the normal side kidney increased from 127.2 mL to 138.8 mL (9.1%) and 140.6 mL (10.9%) after surgery at 6 and 12 months, respectively. The volume of the operated side kidney decreased from 128.5 mL to 102.3 mL (20.1%) and 101.8 (20.6%) after surgery at 6 and 12 months, respectively. In the radical nephrectomy group, older age (P < 0.001), preoperative volume of the normal kidney (P= 0.022) and preoperative GFR for the normal side kidney (P= 0.045) were significant predictors of lower post-surgical GFR at 12 months. In the partial nephrectomy group, older age (P= 0.001) and preoperative volume for both kidneys (P= 0.037) were significant predictors of lower post-surgical GFR at 12 months.

Conclusion: Preoperative kidney volume is an independent predictor of GFR in RCC patients who underwent radical or partial nephrectomy.