A proposal for reclassification of the Fuhrman grading system in patients with clear cell renal cell carcinoma.

Abstract

The conventional Fuhrman grading system, which categorizes renal cell carcinoma (RCC) with grades I, II, III, and IV, is the most widely used predictor assessment of RCC cancer-specific mortality (CSM). The aim of this study was to test the prognostic ability of simplified Fuhrman grading schemes (FGSs) that rely on two- or three-tiered classifications. The current study addressed a population of 14064 patients with clear cell RCC who were treated with partial or radical nephrectomy between 1988-2004, within nine Surveillance, Epidemiology, and End Results (SEER) cancer registries. Univariable and multivariable analyses as well as prognostic accuracy analyses were performed for various FGSs to test their ability to predict CSM rates. The conventional four-tiered FGS was compared to a modified two-tiered FGS in which grades I and II and grades III and IV were combined. A second simplified three-tiered FGS in which grades I and II were combined but grades III and IV were kept separate was also tested. The overall 5-yr CSM-free rate was 81.5%. All three FGSs achieved independent predictor status in multivariable analyses. Prognostic accuracy of multivariable models that relied on various FGSs was 83.6% for the modified two-tiered FGS and 83.8% for both the conventional four-tiered and the modified three-tiered FGS. Our findings indicate that the simplified FGSs perform equally as well as the conventional four-tiered FGS. The use of simplified grading schemes may represent an advantage for pathologists as well as for clinicians caring for patients with RCC.