Preoperative and intraoperative assessment of myometrial invasion in in patients with non-endometrioid endometrial carcinoma—a large-scale, multi-center and retrospective study

Abstract

Abstract Introduction: Myometrial invasion (≤/＞50%) is a prognostic factor for lymph node metastases and decreased survival in non-endometrioid endometrial carcinoma. Our aim was to explore the mode of myometrial invasion diagnosis in FIGO stage I non- endometrioid carcinoma and to evaluate differences of diagnostic efficiency among intraoperative frozen section, gross examination, MRI and CT in clinical practice and to suggest which one should be routinely performed. Method: This is a historical cohort study nationwide (thirty centers in China between January 2000 and December 2019). Clinical data including age, histology, method of myometrial invasion evaluation (MRI, CT, intraoperative gross examination, frozen section) and final diagnosis of postoperative paraffin section were collected from 490 non-endometrioid endometrial carcinoma (serous, clear cell and undifferentiated carcinoma, carcinosarcoma and mixed pathology) women in FIGO stage I. Results: Among the 490 patients, 89.59% were detected with myometrial invasion. The methods reported for myometrial invasion assessment were frozen section in 23.47%, gross examination in 69.59%, MRI in 37.96% and CT in 10.20% of cases. The concordance between intraoperative frozen section and postoperative paraffin section was the highest (Kappa = 0.631, accuracy = 93.04%), followed by gross examination (Kappa = 0.303, accuracy = 82.40%), MRI (Kappa = 0.131, accuracy = 69.35%), and CT (Kappa = 0.118, accuracy = 50.00%). A stable diagnostic agreement between frozen section and final results were found through years (2000–2012 Kappa = 0.776; 2013–2014 Kappa = 0.625; 2015–2016 Kappa = 0.545; 2017–2019 Kappa = 0.652). Conclusion: In China, the assessment of myometrial invasion in non-endometrioid endometrial carcinoma is most often performed with intraoperative gross examination, but the reliability is relatively low in contrast to intraoperative frozen section. In clinical practice, frozen section is a reliable method that can help myometrial invasion accurately assessing and intraoperative decision making (lymph node dissection or not). It should be performed routinely in patients with intrauterine non-endometrioid endometrial carcinoma.