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.
“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