Use of Fuhrman grading system for Japanese patients with renal cell carcinoma.

Abstract

452 Background: In Japan, the 3-tiered system compared with the size of nuclei of normal tubule cell was adopted as the histologic criteria for tumor grading of renal cell carcinoma (RCC) in “General Rule for Clinical and Pathological Studies on Renal Cell Carcinoma”. Fuhrman grading system is first adopted in the 4th edition (April, 2011). We evaluated the impact of these pathological features on RCC survival and recurrence in Japanese patients. Methods: We identified 187 consecutive patients who underwent partial or radical nephrectomy at our institution from 1996 to 2009 for RCC. Specimens were re-reviewed by a single pathologist (NK) blinded to clinical outcome data. The data captured were histological type according to the 2004 WHO classification and conventional Fuhrman grading system. Results: Median followup was 57 months (range 5 to 181). Median age at diagnosis was 65 years. The TNM stage (7th UICC) was I in 127 cases, II in 21, III in 20 and IV in 19. A total of 24 partial and 163 radical nephrectomies were performed. Of the specimens 144 (77.0%) were clear cell carcinoma. The metastasis-free survival rates in stage I, II and III at 5 years were 89.7% ,79.8% and 52.1%, respectively (p<0.001). Univariate analysis revealed that there were significant risk factors in T stage, in Furhman grade, in microscopic venous invasion, in capsular invasion and in tumor size more than 4.1cm diameter. On multivariate analysis Furhman grade (grade I and II vs. III, vs. IV) was the only significant risk factor (HR 4.35 (III vs. I and II), HR 3.33 (IV vs. I and II), p=0.037). The overall survival rates in stage I, II , III and IV at 5 years were 83.0%, 90.0%, 76.8% and 41.8%, respectively (p<0.001). On multivariate analysis T stage, capsular invasion and Furhman grade (p=0.003) were the significant risk factor. Conclusions: Even Japanese patients with renal cell carcinoma undergoing nephrectomy, Fuhrman grading system is the most important predictive factor for survival and disease-free survival.