[823] Chromophobe Renal Cell Carcinoma: Is Grading Necessary?

John C Cheville, William R Sukov, Christine M Lohse, Houston R Thompson, Bradley C Leibovich. Mayo Clinic, Rochester, MN

Background: It has been demonstrated that Fuhrman grading is not appropriate for chromophobe renal cell carcinoma (ChRCC). The objective of this study was to determine if nucleolar grading and the recently described ChRCC grading system by Paner et al. (Am J Surg Pathol 2010;34:1233-1240) provide prognostic information.
Design: Pathologic features of 185 patients with ChRCC treated surgically between 1970-2006 were reviewed including nucleolar grade, ChRCC grade, the 2010 TNM groupings, sarcomatoid differentiation, and coagulative tumor necrosis. Cancer-specific (CS) survival was estimated using the Kaplan-Meier method and associations with CS survival were evaluated using Cox proportional hazards regression models.
Results: Twenty-three patients died from ChRCC at a mean 3.0 years (yrs) following surgery (median 1.3; range 0-16) with estimated CS rates (95% CI) at 5, 10 and 15 yrs following surgery of 89% (84-94), 86% (81-92) and 85% (78-91), respectively. Univariate associations with CS survival included the 2010 TNM stage groupings, sarcomatoid differentiation, coagulative tumor necrosis, ChRCC grade, and nucleolar grade (all p<0.001). These last four features remained significantly associated with CS survival after adjusting for the 2010 TNM stage groupings. When the analysis was restricted to the 155 patients with non-sarcomatoid TNM stage groupings I and II ChRCC, only stage grouping (I vs II) was significantly associated with CS survival (p=0.03).
Conclusions: Although the ChRCC grading system described by Paner et al and nucleolar grade are associated with CS survival in ChRCC, they add no additional prognostic information once TNM stage and sarcomatoid differentiation are assessed.
Category: Genitourinary (including renal tumors)

Tuesday, March 20, 2012 9:30 AM

Poster Session III # 160, Tuesday Morning

 

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