To externally validate a mathematical formula for tumor contact surface area (CSA) as a predictor of post-operative renal function in patients undergoing partial nephrectomy for renal cell carcinoma.
A prospectively maintained kidney cancer database was queried for patients who underwent partial nephrectomy between 2014 and 2016. CSA was calculated using data obtained from pre-operative cross sectional imaging. The correlation between CSA and peri-operative variables was examined. Correlation between postoperative renal functional outcomes, CSA, and R.E.N.A.L. nephrometry score (NS) was assessed.
257 patients underwent partial nephrectomy and had sufficient data to enter the study. Median CSA was 14.5 (IQR 6.2-36) cm(2) and median NS was 9 (IQR 7-10). Spearman correlation analysis showed that CSA was correlated with EBL (rs = 0.42, p<0.001), LOS (rs = 0.18, p=0.005), PCE (rs = -0.77, p<0.001) and ACE (rs = -0.78, p<0.001). Both CSA and NS were independent predictors of absolute change in eGFR on multivariable analysis (p<0.001 for both). ROC curve analysis revealed CSA as a better predictor of >20% postoperative decline in eGFR compared with NS (AUC 0.94 vs 0.80, respectively).
CSA was correlated with change in post-operative renal function after partial nephrectomy and can be used in conjunction with NS to counsel patients about their risk for renal functional decline after partial nephrectomy.
The Journal of urology. 2017 Sep 20 [Epub ahead of print]
Miki Haifler, Benjamin T Ristau, Andrew M Higgins, Marc C Smaldone, Alexander Kutikov, Amnon Zisman, Robert G Uzzo
Division of Urology, Department of Surgery, Fox Chase Cancer Center, Temple University Health System, Philadelphia, PA, USA; Department of Urology, Itzhak Shamir Medical Center, Tzrifin, Be'er Ya'akov, Israel. Electronic address: ., Division of Urology, Department of Surgery, Fox Chase Cancer Center, Temple University Health System, Philadelphia, PA, USA., Department of Urology, Itzhak Shamir Medical Center, Tzrifin, Be'er Ya'akov, Israel.