544 COMPARING THE VALIDITY AND REPRODUCIBILITY OF THREE RENAL TUMOR SCORING SYSTEMS: C-INDEX VS P.A.D.U.A. VS R.E.N.A.L.

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INTRODUCTION AND OBJECTIVES: C–INDEX, P.A.D.U.A., and R.E.N.A.L. Nephrometry were proposed as standardized scoring systems (SS) to quantify anatomical elements of kidney tumors. The objective of this study was to compare reproducibility and validity of these SS. METHODS: Interobserver reliability was assessed in 50 subjects by weighted kappa. Two residents and one fellow reviewed this subset of patients. Predictive validity was assessed in 100 patients reviewed by one fellow, using Spearman correlations to examine relationships between SS and variables of interest. RESULTS: The interobserver correlations for the C-Index was 0.84 and for P.A.D.U.A. was 0.81, for R.E.N.A.L. was 0.92 demonstrating excellent reliability. The correlations between the three tumor rating systems were: C-Index and P.A.D.U.A. p 0.0001; C-Index and R.E.N.A.L. p 0.0001; P.A.D.U.A. and R.E.N.A.L. p 0.0001. Correlations with actual tumor size were significant for each of the SS (C-Index p 0.0001; P.A.D.U.A. p 0.0002; R.E.N.A.L. p 0.006). There were no significant correlations with any of the SS and the presence of intraoperative and postoperative complications, operative time or blood loss. There were no significant correlations with length of hospitalization for P.A.D.U.A. or R.E.N.A.L. However, longer hospital stay was significantly associated with lower C-Index scores (p 0.04). All three SS were significantly correlated with duration of warm ischemia (C-Index p 0.0001; P.A.D.U.A. p 0.02; R.E.N.A.L. p 0.001) and % change in creatinine comparing preoperative to postoperative laboratory assessment (C-Index p 0.0009; P.A.D.U.A. p 0.0003; R.E.N.A.L. p 0.001). CONCLUSIONS: All three scoring systems represent novel methods of quantitative describing renal tumors in a standardized manner with reproducible interobserver assessments. All SS analyzed were predictors of warm ischemia time, % change in creatinine, and tumor size. They did not, however, correlate with any other perioperative parameters investigated. At this time, these SS provide a common language for describing renal tumors but their prognostic value is yet to be fully elucidated.