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Purpose: Preoperative estimation of new baseline glomerular filtration rate after partial nephrectomy or radical nephrectomy for renal cell carcinoma has important clinical implications. However, current predictive models are either complex or lack external validity. We aimed to develop and validate a simple equation to estimate postoperative new baseline glomerular filtration rate., Materials and Methods: For development and internal validation of the equation, a cohort of 7,860 patients with renal cell carcinoma undergoing partial nephrectomy/radical nephrectomy (2005-2015) at the Veterans Affairs National Health System was analyzed. Based on preliminary analysis of 94,327 first-year postoperative glomerular filtration rate measurements, new baseline glomerular filtration rate was defined as the final glomerular filtration rate within 3 to 12 months after surgery . Multivariable linear regression analyses were applied to develop the equation using two-thirds of the renal cell carcinoma Veterans Administration cohort. The simplest model with the highest coefficient of determination (R 2 ) was selected and tested. This model was then internally validated in the remaining third of the renal cell carcinoma Veterans Administration cohort. Correlation/bias/accuracy/precision of equation were examined. For external validation, a similar cohort of 3,012 patients with renal cell carcinoma from an outside tertiary care center (renal cell carcinoma-Cleveland Clinic) was independently analyzed., Results: New baseline glomerular filtration rate (in ml/minute/1.73 m 2 ) can be estimated with the following simplified equation: new baseline glomerular filtration rate = 35 + preoperative glomerular filtration rate (× 0.65) - 18 (if radical nephrectomy) - age (× 0.25) + 3 (if tumor size >7 cm) - 2 (if diabetes). Correlation/bias/accuracy/precision were 0.82/0.00/83/-7.5-8.4 and 0.82/-0.52/82/-8.6-8.0 in the internal/external validation cohorts, respectively. Additionally, the area under the curve (95% confidence interval) to discriminate postoperative new baseline glomerular filtration rate ≥45 ml/minute/1.73 m 2 from receiver operating characteristic analyses were 0.90 (0.88, 0.91) and 0.90 (0.89, 0.91) in the internal/external validation cohorts, respectively., Conclusions: Our study provides a validated equation to accurately predict postoperative new baseline glomerular filtration rate in patients being considered for radical nephrectomy or partial nephrectomy that can be easily implemented in daily clinical practice.

Objectives: To evaluate the utility of parenchymal volume analysis (PVA) for estimation of split renal function (SRF) in patients with renal masses. SRF is important for deciding about partial vs radical nephrectomy (PN/RN) and assessing risk for developing severe chronic kidney disease after surgery. For renal donors PVA is routinely used to estimate SRF, but the utility of PVA for the more complex renal mass population remains undefined., Patients and Methods: All patients (n = 374) with renal tumours and a normal contralateral kidney managed with PN (2010-2018), with preoperative/postoperative nuclear renal scans (NRS) and cross-sectional imaging were analysed. Parenchymal volumes were measured by free-hand scripting or software analysis. Concordance between ipsilateral estimated glomerular filtration rate (eGFR) values based on SRF from NRS vs PVA were evaluated by Pearson correlation and Bland-Altman plots. Parallel analysis of all 155 patients managed with RN at our centre (2006-2016) with preoperative NRS and imaging was also performed., Results: For PN, the median age and tumour size were 62 years and 3.4 cm, respectively. The median preoperative ipsilateral parenchymal volume and eGFR were 181 cm 3 and 36.9 mL/min/1.73 m 2 , respectively. Parenchymal volumes estimated by free-hand scripting vs software analyses correlated strongly (r = 0.98, P < 0.001). Preoperative ipsilateral eGFR based on SRF from PVA vs NRS also correlated strongly (r = 0.94, P < 0.001). Ipsilateral eGFR saved after PN correlated strongly with parenchymal volume preserved (all r >0.60); however, the correlation was much stronger when ipsilateral eGFRs were based on SRF from PVA rather than NRS (z-statistic = 3.15, P = 0.002). For RN patients, preoperative eGFR in the contralateral kidney based on SRF from PVA vs NRS also correlated strongly (r = 0.87, P < 0.001)., Conclusion: PVA has utility for estimation of SRF in patients with renal masses, even though this population is older and more comorbid than renal donors and the tumour can complicate the analysis. PVA can be obtained by software analysis from preoperative cross-sectional imaging and thus readily incorporated into routine clinical practice., (© 2020 The Authors BJU International © 2020 BJU International Published by John Wiley & Sons Ltd.)

Objective: To evaluate whether excised parenchymal mass (EPM) during partial nephrectomy (PN) correlates with functional decline and can serve as a surrogate for functional outcomes.Materials and Methods: All 215 patients managed with PN for unifocal renal mass with necessary studies to determine EPM and percent glomerular filtration rate (GFR) and parenchymal mass preserved (both global and specific to the operated kidney) were analyzed. EPM was estimated from the pathologic specimen by subtracting the tumor mass from the specimen mass, with both calculated using the elliptical formula. Vascularized parenchymal mass preserved was measured from computed tomography scans obtained <2 months prior and 3-12 months after surgery. All functional analyses were required to be within the same time frames, and patients with a contralateral kidney were also required to have nuclear renal scans.Results: The median tumor size was 3.5 cm and the median R.E.N.A.L. was 7. Warm and cold ischemia were utilized in 123 and 92 patients, respectively (median ischemia time = 23 minutes). The median global GFR preserved was 89%, the median total parenchymal mass preserved was 93%, and the median estimated EPM was 16 cm3. Whereas percent parenchymal mass preserved correlated strongly with global and ipsilateral GFR preserved (both P < .001), EPM failed to correlate with functional outcomes on both univariable and multivariable analyses.Conclusion: Our data suggest that parenchymal mass preserved with standard PN by experienced surgeons associates strongly with function preserved, whereas EPM fails to correlate with functional outcomes. Further study of the functional impact of EPM in other circumstances will be required, such as enucleation or PN performed by less-experienced surgeons. [ABSTRACT FROM AUTHOR]