Interobserver Agreement for Endometrial Cancer Characteristics Evaluated on Biopsy Material
S Nofech-Mozes, N Ismiil, V Dube, RS Saad, Z Ghorab, A Grin, M Katic, MA Khalifa. Sunnybrook Health Sciences Centre, Toronto, Canada; University of Toronto, Toronto, Canada; Institute for Clinical Evaluative Sciences, Toronto, Canada
Background: A shift towards a disease-based therapy applied according to patterns of failure predicted by pathologic determinants has recently led to considering a selective approach to lymphadenectomy for endometrial cancer in some North American Centers. Accordingly, lymph node dissection can be avoided in low risk patients (endometrioid histology, FIGO grade 1 and 2, <50% myoinvasion and <2 cm primary tumor diameter) whilst should be systematically applied in all non-low risk population. Therefore, it became critical to examine the agreement among pathologists regarding the cell type and grade of endometrial cancer evaluated on preoperative endometrial samples.
Design: This study assessed the diagnostic agreement by comparing the interpretations of 6 raters, with special expertise in gynecologic pathology. Pathologists independently assessed 105 consecutive endometrial biopsies originally reported as positive for endometrial cancer for cell type (endometrioid versus non-endometrioid), tumor grade (FIGO 3-tiered and 2-tiered), nuclear grade and risk category (low risk: endometrioid grade 1+2 and nuclear grade<3). Interrater agreement levels in each category were analyzed by the Fleiss' multiple-rater Kappa statistics with standard error (SE).
Results: Interrater agreement levels were substantial for identification of non-endometrioid histology (=0.63; SE=0.025), high tumor grade (=0.64; SE=0.025) and risk category (=0.66; SE=0.025). The overall was moderate for cell type (=0.54; SE=0.021) due to disagreement on few cases that bordered on atypical complex hyperplasia. The overall agreement was fair for nuclear grade (=0.21; SE=0.025) although the agreement on identification of nuclear grade 3 was moderate (=0.52; SE=0.016).
Conclusions: There is agreement among pathologists in identifying high risk pathologic determinants on endometrial biopsies with cancer. This ascertainment is critical to substantiate the paradigm shift in surgical staging of patients with endometrial cancer.
Wednesday, March 11, 2009 1:00 PM
Poster Session VI # 142, Wednesday Afternoon