Objective The prognosis of endometrial cancer depends on the correct surgical staging. In early stages, 18% to 30% rate of positive lymph nodes is reported with a myometrial invasion of 50% or more. According to this, patients with International Federation of Gynecology and Obstetrics stage Ib would benefit from staging lymphadenectomy. Therefore, it is important to classify these patients preoperatively to plan the surgery. In the recent years, 3-dimensional (3D) ultrasound and diffusion-weighted magnetic resonance imaging (DW-MRI) have been incorporated in the preoperative management of these patients. The aim of this study was to assess the usefulness of 3D ultrasound and DW-MRI as predictor of myometrial invasion in endometrial cancer.

Material and Methods We retrospectively compared the assessment of myometrial invasion by 3D ultrasound and DW-MRI with final pathologic evaluation on hysterectomy specimens, in 98 patients diagnosed of early-stage endometrial cancer, who underwent surgery at the Hospital Clinic of Barcelona between 2012 and 2015.

Results Evaluation of the depth of myometrial invasion with 3D ultrasound had a sensitivity, specificity, and accuracy of 77%, 83% and 81%, respectively. Evaluation of the depth of myometrial invasion with DW-MRI had a sensitivity, specificity, and accuracy of 69%, 86%, and 81%, respectively. Association of both techniques improved all the values, showing a sensitivity, specificity, and accuracy of 87%, 93%, and 91%, respectively. In both 3D ultrasound and DW-MRI, the presence of leiomyomas was the first detectable cause of false negative (3% and 4%, respectively) and false-positive (3% and 1%, respectively).

Conclusions We conclude that the implementation of the 2 studies in early-stage endometrial cancer provides low false-negatives and false-positives rates. In cases of patients with leiomyomas, adenomiosis, or intrauterine fluid collection, definitive evaluation of myometrial invasion could be better deferred to intraoperative biopsy in an attempt to reduce false-negatives and false-positives rates.