Transvaginal/transrectal ultrasound for assessing myometrial invasion in endometrial cancer: a comparison of six different approaches

OBJECTIVE: To compare the diagnostic performance of six different approaches for assessing myometrial infiltration using ultrasound in women with carcinoma of the corpus uteri. METHODS: Myometrial infiltration was assessed by two-dimensional (2D) transvaginal or transrectal ultrasound in 169 consecutive women with well (G1) or moderately (G2) differentiated endometrioid type endometrial carcinoma. In 74 of these women three-dimensional (3D) ultrasound was also performed. Six different techniques for myometrial infiltration assessment were evaluated. The impression of examiner and Karlsson's criteria were assessed prospectively. Endometrial thickness, tumor/uterine 3D volume ratio, tumor distance to myometrial serosa (TDS), and van Holsbeke's subjective model were assessed retrospectively. All subjects underwent surgical staging within 1 week after ultrasound evaluation. Definitive histopathological data regarding myometrial infiltration was used as gold standard. Sensitivity and specificity for all approaches were calculated and compared using McNemar test. RESULTS: The impression of examiner and subjective model performed similarly (sensitivity 79.5% and 80.5%, respectively; specificity 89.6% and 90.3%, respectively). Both methods had significantly better sensitivity than Karlsson's criteria (sensitivity 31.8%, p<0.05) and endometrial thickness (sensitivity 47.7%, p<0.05), and better specificity than tumor/uterine volume ratio (specificity 28.3%, p<0.05) and TDS (specificity 41.5%, p<0.05). CONCLUSION: Subjective impression seems to be the best approach for assessing myometrial infiltration in G1 or G2 endometrioid type endometrial cancer by transvaginal or transrectal ultrasound. The use of mathematical models and other objective 2D and 3D measurement techniques do not improve diagnostic performance.