The ability of ADC measurements in the assessment of patients with stage I endometrial carcinoma based on three risk categories

Background Better selection of patients with intermediate and high-risk stage I endometrial carcinoma (EC) for lymphadenectomy has an important effect on the prognosis. Purpose To investigate the role of apparent diffusion coefficient (ADC) measurements in the assessment of stage I EC patients based on three risk categories. Material and Methods We retrospectively studied 80 patients with EC and 28 cervical cancer patients with normal endometrium. 1.5-T conventional magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI) (b = 0, 1000 s/mm(2)) were performed, and ADC values were calculated. Sixty-eight stage I EC patients were divided into three groups: low-risk EC (group 1); intermediate-risk EC (group 2); and high-risk EC (group 3). The remaining 12 EC patients were in stages II and III. Intraclass coefficient, Mann-Whitney U test, Kruskal-Wallis test, and receiver operating characteristics were used for statistical analysis. Results The mean ADC values ( x 10(-3) mm(2) /s) were 0.851 +/- 0.131, 0.734 +/- 0.108, and 0.710 +/- 0.108 for groups 1, 2 and 3, respectively. Significant statistical differences were achieved for the three groups (P = 0.0005). The mean ADC values of group 1 were significantly lower than those in group 2 + 3 (0.725 +/- 0.106; P = 0.0001). For the prediction of groups 2 + 3, the area under the curve of 0.786 and the cut-off value of <= 0.742 were identified, with a sensitivity, specificity, and accuracy of 66.67%, 84.09%, and 73.53%, respectively. Conclusion ADC measurements may have the potential to select intermediate-risk and high-risk stage I EC patients for lymphadenectomy.