587 DIFFERENTIATION OF NON CLEAR RENAL CELL CARCINOMA FROM CLEAR CELL RENAL CELL CARCINOMA USING CT WASHOUT FORMULA A RETROSPECTIVE STUDY

Abstract

You have accessJournal of UrologyKidney Cancer: Evaluation and Staging I1 Apr 2012587 DIFFERENTIATION OF NON CLEAR RENAL CELL CARCINOMA FROM CLEAR CELL RENAL CELL CARCINOMA USING CT WASHOUT FORMULA A RETROSPECTIVE STUDY Ryan P. Kopp, Lejla Aganovic, Kerrin L. Palazzi, and Ithaar H. Derweesh Ryan P. KoppRyan P. Kopp San Diego, CA More articles by this author , Lejla AganovicLejla Aganovic San Diego, CA More articles by this author , Kerrin L. PalazziKerrin L. Palazzi San Diego, CA More articles by this author , and Ithaar H. DerweeshIthaar H. Derweesh San Diego, CA More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2012.02.663AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Renal tumor subtypes are distinct biological entities. Emerging data describe differential patterns of contrast enhancement for different renal neoplasms. We investigated the utility of application of contrast washout formula to predict renal tumor histology after 4−phase computerized tomography (CT). METHODS Two center retrospective cohort study of 163 patients with 4−phase CT for renal masses obtained 10/2002 to 7/2011. Pathology confirmed clear cell (CC−RCC; n=92), papillary (Pa−RCC; n=43), chromophobe (Ch−RCC; n=6), oncocytoma (OC; n=11), or angiomyolipoma (AML; n=11) histology. Demographics, comorbidities, disease characteristics, and preoperative creatinine were recorded. Imaging was interpreted by a radiologist (LA) who recorded tumor size, density measurements in Hounsfield Units (HU), composition, collecting system entry, necrosis, and cystic components. Data were analyzed within subgroups based on histology. Washout was calculated by the formula (Mass Nephrographic HU − Mass Delayed HU)/(Mass Nephrographic HU − Mass Noncontrast HU) and used to calculate sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV). RESULTS Significant differences existed in age (p<0.001), sex (P<0.001), history of diabetes (p=0.005), and preoperative creatinine (p=0.008) between histological subgroups. Tumor size was largest among CC−RCC and smallest among AML (p<0.001). Homogeneous composition was more common among Pa−RCC and Ch−RCC (p<0.001). Overall 25 (15.3%) of tumors had washout <0. Tumors with washout value <0 were Pa−RCC 24/43 (56%), and Ch−RCC 1/6 (14%). No patients with CC-RR, OC, or AML had washout value <0. Washout value <0 had a specificity of 99.2% for Pa−RCC and 100% for non−CC−RCC. Washout value ≥0 had a sensitivity and NPV of 100% for CC−RCC, OC, and AML. Washout value ≥0 had a specificity of 35.2% and a PPV of 66.7% for CC-RCC. CONCLUSIONS Washout value <0 is highly specific for Pa−RCC and non−CC−RCC. Washout value ≥0 is highly sensitive for CC−RCC, OC, and AML. These findings may provide a further tool for clinical decision making and risk stratification. Additional prospective analysis is warranted. © 2012 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 187Issue 4SApril 2012Page: e239-e240 Advertisement Copyright & Permissions© 2012 by American Urological Association Education and Research, Inc.MetricsAuthor Information Ryan P. Kopp San Diego, CA More articles by this author Lejla Aganovic San Diego, CA More articles by this author Kerrin L. Palazzi San Diego, CA More articles by this author Ithaar H. Derweesh San Diego, CA More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...