Evaluating the diagnostic performance of preoperative endometrial biopsies in patients diagnosed with high grade endometrial cancer: A study of the Society of Gynecologic Oncology (GOC) Community of Practice (CoP) Kizanee Jegatheeswaran a , Beatrice Cormier b , Samantha Dube b , Walter Henri Gotlieb c , Limor Helpman d , Janice S. Kwon e , Susie Lau c , Sarah Mah e , Taymaa May f , Dima Saab a , Maggie McNeill d , Marie Plante g , Marie Claude Renaud g , Sarah Shamiya a , Danielle Vicus a,h , Carlos Parra-Herran i,j , Tomer Feigenberg a,k, ⁎ a Department of Obstetrics and Gynecology, Division of Gynecologic Oncology, University of Toronto, Canada b Department of Obstetrics and Gynecology, Division of Gynecologic Oncology, Université de Montreal, Canada c Department of Obstetrics and Gynecology, Division of Gynecologic Oncology, Jewish General Hospital, McGill University, Canada d Department of Obstetrics & Gynecology, Division of Gynecologic Oncology, McMaster University, Canada e Department of Obstetrics and Gynecology, Division of Gynecologic Oncology, University of British Columbia, Canada f Division of Gynecologic Oncology, Princess Margaret Cancer Center, Canada g Gynecologic Oncology Division, CHU de Québec-Hôtel-Dieu de Québec-Université Laval, Canada h Department of Obstetrics and Gynecology, Division of Gynecologic Oncology, Sunnybrook Health Sciences Centre, Canada i Department of Laboratory Medicine, University of Toronto, Canada j Department of Laboratory Medicine, Sunnybrook Health Sciences Centre, Canada k Department of Obstetrics and Gynecology, Division of Gynecologic Oncology, Trillium Health Partners, Canada HIGHLIGHTS • Endometrial biopsies accurately predict high grade cancer in 80% of cases. • Endometrial biopsies are more accurate when reported by a gynecologic pathologist. • Discrepancy in endometrial biopsy interpretation impacts clinical management. • Surgical staging should not be based solely on preoperative endometrial biopsy. abstract article info Article history: Received 8 April 2020 Accepted 30 June 2020 Available online xxxx Keywords: Endometrial cancer Endometrial biopsy Pathology Surgical staging Background. High grade cancers account for a disproportionate number of recurrences in patients with endo- metrial cancer. Accurately identifying these cases on endometrial biopsies allows for better surgical planning. This study evaluates the diagnostic accuracy of general pathologists (GP) compared to gynecological pathologists (GYNP) in interpreting preoperative biopsies. Methods. A retrospective cohort study was conducted of patients diagnosed with high grade endometrial can- cer (HGEC) between 2012 and 2016 at eight Canadian cancer centres. Data was collected from medical records. Pre-operative biopsies were categorized into groups; biopsies read by GP, GYNP and GP reviewed by GYNP. Rates of HGEC on pre-operative biopsy were calculated. Fisher exact test was used to compare differences between the groups. Univariate logistic regression analysis was conducted for HGEC prediction. Results. Of 1237 patients diagnosed with HGEC, 245 (19.8%) did not have a preoperative diagnosis of high- grade disease. Discordancy was identified in 91/287 (31.71%) of biopsies reported by GP, and in 114/910 (12.53%) of biopsies reported by a GYNP (p b 0.0001). Compared to GP, GYNP were 3.24 (CI 2.36–4.45) times more likely to identify high grade disease on preoperative biopsy. Patients whose biopsy was reported by a GYNP were more likely to have a comprehensive staging procedure (OR 1.77 CI 1.33–2.38) and less likely to re- ceive adjuvant therapy (OR 0.71 CI 0.52–0.96). Conclusion. GYNP are more likely to identify HGEC on pre-operative biopsies. Due to high rates of overall Gynecologic Oncology xxx (2020) xxx ⁎ Corresponding author at: 2200 Eglington Avenue West, Department of Obstetrics and Gynecology, Mississauga, ON L5M 2N1, Canada. E-mail address: Tomer.feigenberg@thp.ca (T. Feigenberg). YGYNO-978030; No. of pages: 6; 4C: https://doi.org/10.1016/j.ygyno.2020.06.510 0090-8258/© 2020 Published by Elsevier Inc. Contents lists available at ScienceDirect Gynecologic Oncology journal homepage: www.elsevier.com/locate/ygyno Please cite this article as: K. Jegatheeswaran, B. Cormier, S. Dube, et al., Evaluating the diagnostic performance of preoperative endometrial biopsies in patients diagnosed wit..., Gynecologic Oncology, https://doi.org/10.1016/j.ygyno.2020.06.510