[786] Determining Carcinoma Extent Based on Percentage in Radical Prostatectomy (RP) Specimens by Non-Genitourinary Pathologists (N-GUPs) and Pathology Trainees (PTs).

Virginia Dailey, Omar Hameed, Prostate Carcinoma Extent Group. University of Alabama at Birmingham

Background: It is recommended that some measurement of tumor extent be provided when reporting carcinoma in RP specimens. We previously demonstrated that there was excellent agreement between visual tumor extent measurements among GUPs and image analysis. The aim of this study was to see if this can be replicated in N-GUPs and PTs.
Design: Replicate slides (n=108) of 10 partially-embedded RP specimens (9-15 slides/case) were circulated to 7 N-GUPs and 9 PTs. PTs were first asked to estimate percentage of carcinoma in 5 specimens without any additional instructions. Following distribution of written instructions, all participants were asked to estimate the percentage of prostatic tissue involved by carcinoma in each section and to use the average to derive the total percentage of prostate involved by tumor. These percentages were broken down into 4 categories (< 5%, 6% to 20%, 21% to 50%, and > 50%) that have been found to correlate well with outcome (Urol. 2008;180:571) and compared with those obtained by image analysis to obtain agreement statistics. These were then compared with the agreement statistics among GUPs.
Results: Although there were no significant differences in the agreement rates (ARs) and kappa values between N-GUPs and PTs, they were significantly different from those among GUPs (Table). Both N-GUPs and PTs were more likely to underestimate the extent of carcinoma compared to GUPs. There was no correlation between years of experience (6-37 years; mean 22 years) and agreement statistics among N-GUPs. Although written instructions led to higher mean ARs (64% vs. 71%) and kappa values [0.57 vs. 0.60 (unweighted) and 0.67 vs. 0.72 (weighted)] among PTs, the differences were not statistically significant.
Conclusions: N-GUPs and PTs tend to underestimate the extent of prostatic carcinoma based on visual estimation. This could be potentially improved by additional training of pathology residents and fellows.

Category: Genitourinary (including renal tumors)

Monday, February 28, 2011 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 96, Monday Morning


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