The Potential Value of a Simple Two-Level Grading System for Renal Cell Carcinomas
LP Herrera, M Jorda, I Reis, D Sanz, E Viera, M Nadji. University of Miami/Jackson Memorial Hospital/UM Sylvester Cancer Center, Miami, FL; UM/Sylvester Division of Biostatistics, University of Miami Miller School of Medicine, Miami, FL
Background: The Fuhrman nuclear grade (FG) is the most widely used prognostic factor for renal cell carcinoma (RCC). The interobserver reproducibility of this system however, is relatively low particularly between grades II and III and occasionally between grades III and IV. In this study we investigated the potential value of a simplified 2-level grading system (2G), low and high-grade, in predicting survival and metastatic behavior in the two most common types of RCC, conventional and papillary.
Design: Archival nephrectomy specimen slides from 104 patients with the diagnosis of conventional and papillary RCC were reviewed by 2 pathologists independently. We reassessed Fuhrman nuclear grade (FG) and pathological stage. We grouped tumors of FG I and II as low-grade and FG III and IV as high. Clinical follow-up was available for all cases. Fisher's exact test was used to examine associations between variables. Overall survival was estimated by Kaplan-Meier method and the effect of prognostic factors was examined by log-rank test and Cox proportional hazards models.
Results: Of the 104 cases of RCC, 81 were classified as conventional and 23 as papillary type. Forty-five cases (43%) were stage 1, 26 (25%) stage 2, 21 (20%) stage 3 and 12 (12%) stage 4. Seventy-nine (75%) patients were alive after a median time of 4 years, and 25 (24%) died of disease, with a median time to event of 2.3 years. FG I tumors accounted for 24 (23%), II 49 (47%), III 25 (24%) and IV 6 (6%). After grouping the cases using the 2G system, low-grade tumors accounted for 70% (73) and high-grade neoplasms for 30% (31). Both, the classic FG and the 2G, provide similar significant information regarding metastatic behavior and overall survival (p<0.05). When using the 2G, patients with high-grade neoplasms had a 2.9 fold increased risk of death as compared with patients with low-nuclear grade tumors (p=0.008). The agreement between the two pathologists was 73% for FG and 96% for 2G system.
Conclusions: The 2G system in RCC is a predictor of metastatic behavior and overall survival similar to the classic FG system. The use of the 2G system, however, is simple and may result in a better interobserver reproducibility.
Category: Genitourinary (including renal tumors)
Tuesday, March 10, 2009 1:15 PM
Platform Session: Section A, Tuesday Afternoon