Dynamic contrast‐enhanced ultrasound improves diagnostic performance in endometrial cancer staging

Abstract

To compare the sensitivity and specificity of conventional two-dimensional transvaginal ultrasound/power Doppler (2D-TVU/PD) alone and 2D-TVU/PD combined with dynamic contrast-enhanced ultrasound (DCE-US) in diagnosing deep myometrial invasion (MI) and cervical stromal involvement (CSI) in women with endometrial cancer (EC), and to assess the association of DCE-US semiquantitative and qualitative variables with International Federation of Gynecology and Obstetrics (FIGO) Stage ≥ IB and 'high-risk' cancer. This was a prospective study of 101 consecutive women with biopsy-confirmed EC, undergoing expert ultrasound examination at Karolinska University Hospital, a tertiary referral center. All consenting women underwent DCE-US using a 1.5-2.5-mL intravenous bolus of SonoVue contrast agent, as well as conventional 2D-TVU/PD examination. DCE-US videoclips were analyzed with regard to filling (global or focal), wash-in (prior, simultaneous or after) and wash-out (global or focal) patterns of the contrast agent in the tumor compared with the surrounding tissue, as well as semiquantitative DCE-US parameters (wash-in slope, time-to-peak, peak intensity and area under the time-intensity curve (TIC)) obtained from a TIC. The study cohort was compared with a control cohort of women with EC examined at our center according to the International Endometrial Tumor Analysis protocol using 2D-TVU/PD only, matched at a ratio of 3:1 for FIGO stage and grade. The sensitivity and specificity of 2D-TVU/PD alone in the control cohort and in combination with DCE-US in the study cohort in the diagnosis of deep MI, CSI and high-risk cancer (defined as FIGO Stage ≥ IB and/or Grade 3 endometrioid and/or non-endometrioid histology) were compared, using pathological evaluation after hysterectomy as the 'gold standard'. After exclusions, 93 women were included in the study cohort and were matched to 279 women in the control cohort. The prevalence of FIGO Stage IA, Grade 1-2 EC was 52% in both cohorts. The sensitivity of 2D-TVU/PD with DCE-US in the study cohort was higher than that of 2D-TVU/PD alone in the control cohort in diagnosing both deep MI (0.74 vs 0.62; P = 0.036) and CSI (0.75 vs 0.51; P < 0.001), whereas the specificity was not significantly different (0.87 vs 0.85 and 0.96 vs 0.95, respectively). Compared with 2D-TVU/PD alone, the specificity of 2D-TVU/PD with DCE-US was higher in detecting high-risk cancer (0.94 vs 0.85; P = 0.024) but the sensitivity did not differ (0.73 vs 0.71). High-risk cancer and FIGO Stage ≥ IB were characterized by a 'focal' filling pattern, with a 'prior' wash-in pattern and a 'focal' wash-out pattern on subjective assessment of DCE-US videoclips. All semiquantitative DCE-US parameters were significantly predictive of FIGO Stage ≥ IB but not of high-risk cancer, despite a clear trend. Compared with 2D-TVU/PD alone, combining 2D-TVU/PD with DCE-US can significantly improve the detection of deep MI and CSI in women with EC, without increasing the false-positive rate. It can also improve the correct classification of high-risk disease, mainly by increasing specificity, thereby possibly reducing the number of unnecessarily extensive surgeries by almost 10%. Semiquantitative DCE-US parameters, as well as a 'focal' filling pattern, endometrial wash-in prior to the myometrium and a 'focal' wash-out pattern, are all associated with more advanced disease. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.