Presentation Authors: Diego Aguilar Palacios*, Elvis R. Caraballo, Cleveland, OH, Hajime Tanakaa, Tokyo, Japan, Yanbo Wanga, Changchun, China, People's Republic of, Chalairat Suk-Ouichai, Bangkok, Thailand, Lin Lin, Steven C. Campbell, Cleveland, OH
Introduction: Replacement of healthy renal parenchyma by renal cell carcinoma (RCC) can contribute to preexisting CKD and thus complicate management. However the magnitude and factors associated with this phenomenon have not been described.
Methods: A retrospective review was performed of all radical nephrectomies (RN) performed at our center from 2006-2016. 155 patients with available nuclear renal scan and imaging demonstrating a single RCC tumor with normal contralateral kidney were included for analysis. Healthy renal parenchyma of each kidney and tumor volumes were measured by free-hand scripting from axial images at 3 mm intervals. Parenchymal volume discordance (volume ipsilateral kidney - volume contralateral kidney) was calculated assuming that the volume of the contralateral kidney serves as a control to assess replacement of healthy parenchyma by RCC. Split renal function was used as an internal control for volumetric measures. Multiple regression was used to identify preoperative and pathological factors related to parenchymal volume discordance.
Results: Median age was 66 years and 69% of patients were male. Comorbidities included hypertension in 71%, cardiovascular disease in 27%, diabetes in 30%, and active/former smoker in 60%. Preexisting CKD was found in 34% of patients and the median estimated preoperative GFR was 29ml/min/1.73m2 in the involved kidney and 39ml/min/1.73m2 in the contralateral kidney. Median R.E.N.A.L. score was 10 and volume of the tumor, ipsilateral parenchyma and contralateral parenchyma were 111, 147 and 179 cm3 respectively. Locally advanced (â‰¥T3a) tumors were found in 61% and clear cell histology in 73% of cases. Half of the patients had a volume discordance â‰¥ 26 cm3 and a quarter â‰¥53 cm3 which represents 16% and 32% of renal parenchyma replacement by tumor, respectively. Factors independently associated with this parenchymal volume discordance were tumor volume (-0.31 p= < 0.01), T stage (-0.21 p=0.02) and endophytic properties (- 0.20, p=0.01). Linear correlation was confirmed among parenchymal volumetric measures and split renal function (p=0.01).
Conclusions: Substantial replacement of healthy parenchyma by RCC occurs in the majority of patients requiring RN and is mainly driven by tumor characteristics such as endophytic location, tumor volume and T stage.