Background: Aim of this study was to rate the misdiagnosis of histological type between preoperative endometrial biopsy and final postoperative pathology focusing on non-endometrioid endometrial cancer (NEEC). Secondary objective is to assess the concordance between intraoperative assessment and final pathology in a subgroup of patients.
Methods: A multicenter retrospective study was conducted in patients with histological diagnosis of endometrial cancer who underwent surgical staging between 2011 and 2016. The concordance rate and the Kappa Cohen coefficient were calculated to assess the correlation concerning the histological type between endometrial biopsy and final pathology, and between intraoperative assessment and final pathology in a subgroup of patients.
Results: Two hundred ninety-five patients were enrolled, 226 were endometrioid carcinomas and 61 NEEC at final pathology. The concordance rate between pre-operative and final pathology for NEEC and the Kappa Cohen coefficient were 81.4% and 0.41 (CI 95% 0.3059-0.5122), respectively. 26 out of 61 (42.6%) NEEC were preoperatively misdiagnosed. The frozen section was performed in a subgroup of 86 patients (29.15%): the concordance rate between frozen section and final pathology for NEEC was 80% and the Kappa Cohen coefficient was 0.28 (CI 95% 0.212-0.347).
Conclusions: Preoperative pathological histotype assessment predicts final pathology with a moderate grade of accuracy and the identification of NEEC could be challenging. Efforts should be directed toward molecular characterization of diagnostic samples in order to improve diagnostic accuracy and guide therapeutic decisions.