Accuracy of transvaginal ultrasound versus MRI in the PreOperative Diagnostics of low-grade Endometrial Cancer (PODEC) study: a prospective multicentre study

Aim: To investigate if the diagnostic accuracy of transvaginal ultrasound (TVUS) performed by gynaecologists is sufficient for preoperative assessment of low-grade endometrial cancer (EC) compared to magnetic resonance imaging (MRI).

Materials and methods: MRI and TVUS performed by gynaecologists were assessed at the participating centres. The MRI examinations were interpreted by two radiologists at the tertiary centre. Deep myometrial and cervical stroma invasion were visually assessed and compared to postoperative histopathology.

Results: Two hundred and fifty-nine patients were included. There was a statistically significant difference in specificity assessing deep myometrial invasion between MRI and TVUS (MRI 0.88, TVUS 0.68). There was no difference in sensitivity (MRI 0.73, TVUS 0.68). When assessing cervical stroma infiltration, MRI had a higher specificity (MRI 0.96, TVUS 0.90), but there was no difference in sensitivity (MRI 0.41, TVUS 0.32).

Conclusion: MRI has higher specificity than TVUS performed by gynaecologists for assessing deep MI and CSI in low-grade EC, but similar sensitivities. The use of TVUS as a first-line test, rather than MRI, may be supported by this study in centres where access to MRI may be limited.