Diagnostic performance of transvaginal ultrasound and magnetic resonance imaging for the preoperative evaluation of low-grade endometrioid endometrial carcinoma: a single-center prospective comparative study.

OBJECTIVES We aimed to compare the diagnostic performance of transvaginal ultrasound (TVUS) and magnetic resonance imaging (MRI) to predict the depth of myometrial invasion (DMI) and cervical stromal invasion (CSI) in patients with low grade (G1-G2) endometrioid endometrial cancer (EEC). METHODS Prospective and consecutive study including all low-grade EEC diagnosed between October 2013 and July 2018 at the Vall d'Hebron Hospital in Barcelona. Preoperative staging was performed with TVUS and MRI followed by surgical staging. Final histology was considered as the reference standard. Sensitivity, specificity, likelihood ratios and diagnostic accuracy were calculated for both imaging techniques for the prediction of DMI and CSI. The agreement index was calculated for both techniques. The STARD 2015 guidelines were used. RESULTS A total of 131 patients were consecutively included. Sensitivity was higher for TVUS compared to MRI both for the prediction of DMI (68% (95%CI 53-81) versus 51% (95%CI 35-66), respectively) and CSI (43% (95%CI 27-60) versus 24% (95%CI 11-41), respectively). Specificities were similar for the prediction of DMI (TVUS 87% (95%CI 78-93) and MRI 90% (95%CI 82-95)) and equal for CSI (96% (95%CI 90-99). The agreement index between TVUS and MRI was 0,84 (CI95%,0,76-0,90) for the DMI and 0,92 (CI95%, 0,85-0,96) for CSI. CONCLUSIONS The diagnostic performance of TVUS is not inferior to MRI for the prediction of DMI and CSI in low-grade EEC and can play a role as a first line imaging technique in the preoperative evaluation of low-grade EC. This article is protected by copyright. All rights reserved.