[1049] Poor Interobserver Reproducibility in the Diagnosis of High-Grade Endometrial Carcinoma.

C Blake Gilks, Esther Oliva, Rob Soslow. Vancouver General Hospital and BC Children's and Women's Hospital, BC, Canada; Massachusetts General Hospital, Boston; Memorial Sloan Kettering Cancer Center, New York, NY

Background: Patients with endometrial carcinoma who have high-grade subtypes (grade 3 endometrioid, serous, clear cell, carcinosarcoma) have a relatively poor prognosis. There is little information on the reproducibility of subtype diagnosis in cases of high-grade endometrial carcinoma.
Design: Fifty six cases diagnosed as a high-grade subtype of endometrial carcinoma were identified in the archives of VGH. All slides for each case were reviewed independently by three pathologists, who diagnosed the subtype, and assigned a percentage for each component in mixed tumors. Agreement between observers was classified as follows – Major disagreement: A. No consensus for low-grade endometrioid versus high-grade (any subtype) or B. Disagreement with respect to the predominant high-grade subtype present; Minor disagreement: consensus is reached about the cell type of the predominant high-grade component, but there is no agreement regarding a secondary high-grade subtype type.
Results: In 35 of 56 (62.5%) cases there was agreement between all three reviewing pathologists regarding of the predominant subtype of high-grade endometrial carcinoma. In four of these cases (7.1%) there was a minor disagreement i.e. not all observers agreed there was a secondary high-grade subtype present. In 17 of 56 cases (30.4%) there was no consensus between the three observers with respect to the high-grade subtype; in an additional 3 cases (5.4%) there was no agreement between observers with respect to low-grade versus high-grade (any subtype). The final case was diagnosed as low-grade endometrioid carcinoma by all reviewers (but had been previously diagnosed as high-grade). The most frequent areas of disagreement were serous versus clear cell (7/17 cases) and serous versus endometrioid (5/17 cases). Pair-wise comparison between reviewers for cases with major disagreements was as follows: rev. 1 vs rev. 2 – agreement in 5/20 cases, rev. 1 vs rev. 3 – agreement in 7/20 cases, rev. 2 vs rev. 3 – agreement in 9/20 cases.
Conclusions: There were significant major diagnostic disagreements between reviewers in subtyping of high-grade endometrial carcinoma in more than one third of cases. This did not reflect systematic bias on the part of any single reviewer. Although this study was not designed to look at the reproducibility of diagnosis of low versus high-grade endometrial carcinoma, even this distinction proved to be problematic.
Category: Gynecologic & Obstetrics

Wednesday, March 2, 2011 1:00 PM

Poster Session VI # 157, Wednesday Afternoon


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