Prognostic value of renal cell carcinoma nuclear grading: multivariate analysis of 333 cases.

OBJECTIVE: To evaluate the independent predictive value of the nuclear grading system according to Fuhrman in relation to the disease-specific survival of patients with renal clear cell carcinoma.

MATERIAL AND METHODS: 333 patients who underwent radical nephrectomy for renal clear cell carcinoma between 1983 and 1999 were evaluated. In all patients we retrospectively studied nuclear grading, average tumor size, multifocality, pathologic stage of primary tumor, vein invasion, lymph node involvement and distant metastases. The Kaplan-Meier method was applied to evaluate disease-specific survival rates. The log rank test was used to compare survival curves and for univariate analysis. The Cox proportional hazards model was used for the multivariate analysis.

RESULTS: Histologic grade was G1 in 83 cases (25%), G2 in 117 cases (35%), G3 in 110 cases (33%) and G4 in 23 cases (7%). Our data showed that nuclear grading according to Fuhrman is related to medium tumor size (p < 0.0001), pathologic stage of cancer (p < 0.001), venous system invasion (p < 0.001), lymph node involvement (p < 0.001) and distant metastases (p < 0.001). The disease-specific survival after 5 and 10 years was 94 and 88%, respectively, in patients with G1, 86 and 75% in patients with G2, 59 and 40% in patients with G3 and 31% in patients with G4 (log rank p value < 0.0001). Multivariate analysis showed that nuclear grading by Fuhrman has a prognostic independent predictive value (hazard ratio = 1.8461, p = 0.002).

CONCLUSIONS: Nuclear grading is an important independent predictive factor of disease-specific survival in patients with renal cell carcinoma.