Analysis of factors to affect on MR assessment of myometrial invasion and cervical involvement in endometrial cancer.

Objective: The aim of this study was to assess the depth of myometrial invasion and cervical involvement by endometrial cancer using magnetic resonance imaging (MRI). Methods: Forty three patients with histological diagnosis of endometrial cancer were studied with the results of MRI at 1.5T and subsequently underwent staging operation. The MRI results were compared with pathologic results. Presence of large polypoid tumors, leiomyoma, adenomyosis, distension of uterine cavity by large tumor, atrophy of uteri, utetrine anomalies and tumor protruding into the cervical canal were analyzed. Results: On review, the sensitivity for the detection of myometrial invasion was 93.5%, specificity 58.3%, positive predictive value (PPV) 85.3% and negative predictive value (NPV) 77.8%. For the detection of deep myometrial invasion, sensitivity was 87.5%, specificity 85.7%, PPV 58.3% and NPV 96.8%. For the detection of cervical involvement, sensitivity was 100%, specificity 92.9%, PPV 25%, NPV 100%. Distension of uterine cavity by large tumor (p=0.009) and adenomyosis (p=0.041) were associated with incorrect MRI assessment of myometrial invasion. For cervical involvement, tumor protruding into the cervical canal was associated but did not reach statistical significance (p=0.062). Conclusion: MRI scans as reported offered some clinical benefit in preoperative assessment of endometrial cancer, but for assessment of cervical involvement, showed low PPV. When present, distension of uterine cavity by large tumor and adenomyosis may make it difficult to assess myometrial invasion at MR imaging.