For decades, the most widely-used pathological prognostic classification system for patients with renal cell carcinoma (RCC) has been the 4-tier Fuhrman grading system (FGS), which employs microscopic morphological and staining criteria. 

But that system could be condensed into a simple binary system to improve consistency of grade determinations, according to authors of a study from the University of Pennsylvania.1

A simplified 2-tier FGS performed similarly to the conventional 4-tier FGS, reported lead study author Zachary L. Smith, MD, of the Perelman Center for Advanced Medicine at the University of Pennsylvania in Philadelphia.

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“The use of this simplified system may promote greater continuity of pathological interpretation as well as provide a more simplified approach for clinician utilization,” Dr Smith and his coauthors reported.

The conventional FGS classifies RCC into grades 1, 2, 3, or 4. The simplified version combined grades 1 and 2 into a single “low grade” category, and combined the conventional system’s grades 3 and 4 into a “high grade” category.

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Applying the simplified grading scheme to 509 patients diagnosed with clear-cell RCC who underwent radical or partial nephrectomy, the research team found that 5-year cancer-specific survival (CSS) was 75.5% vs. 54.7% for patients categorized as low- versus high-grade in the simplified system (P < .001). That compared well to the traditional 4-tier FGS (5-year CSS: 74%, 76%, 57% and 41% for patients with FGS grade-1, 2, 3, and 4 cancers, respectively).

The new findings bolster those of previous studies, whose authors have also called for a simplified FGS.2