Fuhrman Grading is not Appropriate for Chromophobe Renal Cell Carcinoma

Abstract

This study was undertaken to assess the prognostic effectiveness of Fuhrman nuclear grading and the individual components of this grading system, in a series of chromophobe renal cell carcinomas. Eighty-seven cases of chromophobe renal cell carcinoma were investigated. There were 47 males and 40 females, 28 to 78 years of age. The carcinomas ranged from 25 to 180 mm in size and on TNM staging there were 38 stage I, 25 stage II, 22 stage III, and 2 stage IV tumors. Whole tumor Fuhrman grading was grade 1, 6 cases; grade 2, 72 cases; grade 3, 8 cases; and grade 4, 1 case, whereas focal (single high power field) grading was grade 1, 1 case; grade 2, 62 cases; grade 3, 21 cases; and grade 4, 3 cases. On assignment of nucleolar grading using Fuhrman criteria there were 37 grade 1, 44 grade 2, and 4 grade 3 tumors on whole tumor assessment and 3 grade 1, 63 grade 2, and 21 grade 3 tumors on assessment of the high power field showing the greatest degree of nuclear pleomorphism. Measurements of nuclear size showed nuclear area to range from 26.14 to 100.74 microm2, nuclear perimeter from 19.73 to 39.28 microm, and nuclear major axis from 6.49 to 13.21 microm, whereas the ranges of measures of nuclear shape were; shape factor 0.798 to 0.890, compactness 14.260 to 15.843, and feret diameter 5.694 to 11.242. Follow-up ranged from 1 to 150 months and 8 patients died of tumor-related causes 5 to 53 months from diagnosis. On log rank testing against survival, only patient age (P=0.016) and tumor maximum diameter (P=0.0055) were significant, whereas patient sex and TNM stage were not significant. Whole tumor and focal Fuhrman grading, as well as all measures of nucleolar prominence, nuclear size, and nuclear shape showed no significant association with outcome. It is concluded that neither Fuhrman grading, nor any of the components of the Fuhrman grading system, is useful as prognostic indicators for this tumor type.

Advances and controversies in grading and staging of renal cell carcinoma

“…47,48 For papillary RCC it was found that of the three parameters of the Fuhrman system, neither the morphometric measures of nuclear size nor pleomorphism correlated with outcome. Nucleolar prominence, based on the microscopic high-power field showing the greatest degree of nuclear pleomorphism was significantly associated with outcome on univariate analysis, although this was not independent of pT category or TNM stage.…”

“…47 For chromophobe RCC not one of the three grading components was correlated with outcome, when tested separately, which raises questions as to the validity of Fuhrman grading for these tumors. 48 Importantly, when tumors in both of these series were classified on the basis of nuclear size alone, utilizing the nuclear diameter cut points proposed by Fuhrman, then all tumors were classified as grade 1, whereas assessment of focal nucleolar prominence on its own showed 58% of papillary RCC and 24% of chromophobe RCC to exhibit grade 3 characteristics.…”

FG has no added value in prediction of mortality after partial and radical nephrectomy for chromophobe renal cell carcinoma patients

“…1 To date, 11 studies tested the ability of FG in prediction of prognosis in chromophobe renal cell carcinoma. [2][3][4][5][6][7][8][9][10][11][12] Seven of those failed to confirm the value of FG. [2][3][4][5][6][7][8] However, all relied on small sample sizes (n ¼ 49-291), thus power may have been insufficient.…”

“…[2][3][4][5][6][7][8][9][10][11][12] Seven of those failed to confirm the value of FG. [2][3][4][5][6][7][8] However, all relied on small sample sizes (n ¼ 49-291), thus power may have been insufficient. [2][3][4][5][6][7][8] Conversely, four other reported the opposite findings.…”

“…[2][3][4][5][6][7][8] However, all relied on small sample sizes (n ¼ 49-291), thus power may have been insufficient. [2][3][4][5][6][7][8] Conversely, four other reported the opposite findings. [9][10][11][12] Here, FG was found to accurately predict prognosis and study populations included patients with chromophobe renal cell carcinoma.…”