The Comparison of Three Renal Tumor Scoring Systems: C-Index, PADUA, and RENAL Nephrometry Scores

Background and Purpose: The centrality-index (C-Index), preoperative aspects and dimensions used for anatomic (P.A.D.U.A.) classification, and radius. exophyic/endophytic. nearness. anterior/posterior. location (R.E.N.A.L.) nephrometry schemes were developed as standardized scoring systems (SS) to quantify anatomic characteristics of kidney tumors. The objective of this study was to establish reliability and assess relationships between these three SS and perioperative and postoperative variables. Patients and Methods: A retrospective chart review was performed in 101 patients who underwent laparoscopic partial nephrectomy. The nephrometry schemes were correlated with intraoperative and postoperative parameters using Spearman correlations. In addition, interobserver reliability was assessed on 50 of the patients by interclass correlations comparing the scores assigned by two residents and one fellow who reviewed preoperative CT studies of these patients. Results: The interobserver correlation was 0.84 for the C-Index, 0.81 for the P.A.D.U.A., and 0.92 for the R.E.N.A.L. scoring systems, demonstrating excellent interobserver reliability. All three SS were significantly associated with warm ischemia time (WIT) (C-Index, P = -0.44; P.A.D.U.A., P = 0.25; R.E.N.A.L., P = 0.32) and percent change in creatinine level (C-Index, P = -0.33; P.A.D.U.A., P = 0.37; R.E.N.A.L., P = 0.37). There were no significant associations between any of the three SS assessed and the occurrence of complications, operative time, or estimated blood loss. No significant correlation was found between the P.A.D.U.A. and R.E.N.A.L. SS and length of stay; however, C-Index did show a significant relationship for patients with lower scores having longer hospital stays (P = -0.21). Conclusions: All three scoring systems demonstrated reliability among observers and represent novel methods of quantitatively describing renal tumors. They were all associated with WIT, percent change in creatinine level, 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.