[780] Central Pathology Review Detects Significant Error in Archival Data on Histological Subtype, Grade and Stage for Renal Cell Carcinoma

H Aydin, L Sercia, K Simmerman, B Lane, P Elson, R Baehner, B Rini, M Zhou. Cleveland Clinic, Cleveland; Genomic Health Institute, Redwood

Background: The classification and staging of renal cell carcinoma have undergone major changes recently. Therefore, simply plotting the archival pathology data for current and future studies may not be accurate. We re-evaluated 1280 renal cell carcinomas and established the role of central eview by a subspecilaist in providing up-to-date information for research.
Design: 1280 nephrectomies performed in a single institution between 1985 and 2004 for stage < 3 clear cell RCC (CCRCC) or RCC not otherwise specified (RCCNOS) were collected. The diagnosis and histological typing were done by a genitourinary pathologist using 2004 WHO classification. Fuhrman nuclear grade (FNG), perinephric fat invasion (PNI), and renal sinus invasion (RSI) were also evaluated. Re-review data were compared to the archival one.
Results: 110 (8.6%) cases, originally diagnosed as RCCNOS were not histologically subtyped. 101 (17.9%) were misclassified as CCRCC. The correct diagnoses for misclassified cases were papillary RCC (27, 31.0%), chromophobe RCC (24, 27.6%), oncocytoma (2, 2.3%), oncocytic tumor NOS (5, 5.7%), clear cell papillary RCC (9, 10.3%), leiomyomatous RCC (3, 3.4%), unclassified RCC (16, 18.4 %) and benign tumor (1, 1.1%). In evaluable cases, FNG was changed in 301/775 (38.8%) cases, with significant shift (from grade 1/2 to 3/4 and vice versa) in 180 (23.2%) cases. The over and under grading were 12.8 and 26 % respectively. Also noted were discrepancies in PNI 107/831 (12.9%) and RSI 112/841 (13.3%). Overall pathological stage was changed in 134/827 (16.2%) cases. Over and under staging were 14.4 and 1.8 % respectively.
Conclusions: A significant proportion of cases were originally misclassified, graded and/or staged. Central re-review by a pathologist with specific expertise provides more reliable data for research and potential clinical applications in comparison to using the archival data as it is. Also, it enables identifying recently described histological subtypes that were not originally recorded.
Category: Genitourinary (including renal tumors)

Tuesday, March 23, 2010 9:30 AM

Poster Session III # 148, Tuesday Morning


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