Prognostic value of nuclear grade of renal cell carcinoma

The authors assessed the interest and the value of Fuhrman's nuclear grade as a possible prognostic factor for renal cell carcinoma (RCC).

An 11-year retrospective study of 190 patients with RCC treated by radical nephrectomy was performed. The distribution by grade was: Grade I, 54 patients; Grade II, 58; Grade III, 58; and Grade IV, 20. The distribution of the patients by tumor stage according to the TNM15 classification was: pT1, 56 patients; pT2, 41; pT3a, 55; pT3b, 25; pT3c + pT3d + pT4b, 5; and pT4a, 8. Significant correlations with other prognostic parameters were noted. Survival curves by grade were evaluated by the Kaplan-Meier method.

Nuclear grade was correlated with tumor stage (P = 0.0001), synchronous metastases (P = 0.003), lymph node involvement (P = 0.0001), renal vein involvement (P = 0.0001), tumor size (P = 0.0001), and perirenal fat involvement (P = 0.001). No correlation was found between nuclear grade and tumor multicentricity (P = 0.14) and cell type (P = 0.2). Nuclear grade was an effective parameter in predicting development of distant metastases after nephrectomy. Among the 54 patients who presented with Grade I tumors, only one tumor did metastasize during the 5-year follow-up, whereas 17% of the Grade III and 30% of the Grade IV tumors metastasized. The 5-year actuarial survival rates of the patients with Grade I, II, III, and IV tumors was 76%, 72%, 51%, and 35%, respectively. The comparison of the survival curves by grade showed a statistically significant difference between the curves when Grade I and II tumors were compared with Grade III and IV tumors (P = 0.001).

In this study, nuclear grade was found to have prognostic significance and seems to be an important criterion when considering the outcome of patients with RCC.