Transvaginal ultrasound assessment of myometrial and cervical stromal invasion in women with endometrial cancer: Interobserver reproducibility among ultrasound experts and gynecologists

Abstract

Objectives: To assess interobserver reproducibility among ultrasound experts and gynecologists in the prediction by transvaginal ultrasound of deep myometrial and cervical stromal invasion in women with endometrial cancer. Methods: Sonographic videoclips of the uterine corpus and cervix of 53 women with endometrial cancer, examined preoperatively by the same ultrasound expert, were integrated into a digitalized survey. Nine ultrasound experts and nine gynecologists evaluated presence or absence of deep myometrial and cervical stromal invasion. Histopathology from hysterectomy specimens was used as the gold standard. Results: Compared with gynecologists, ultrasound experts showed higher sensitivity, specificity and agreement with histopathology in the assessment of cervical stromal invasion (42% (95% CI, 31-53%) vs 57% (95% CI, 45-68%), P < 0.01; 83% (95% CI, 78-86%) vs 87% (95% CI, 83-90%), P = 0.02; and kappa, 0.45 (95% CI, 0.40-0.49) vs 0.58 (95% CI, 0.53-0.62), P < 0.001, respectively) but not of deep myometrial invasion (73% (95% CI, 66-79%) vs 73% (95% CI, 66-79%), P = 1.0; 70% (95% CI, 65-75%) vs 69% (95% CI, 63-74%), P = 0.68; and kappa, 0.48 (95% CI, 0.44-0.53) vs 0.52 (95% CI, 0.48-0.57), P = 0.11, respectively). Though interobserver reproducibility (in the context of test proportions 'good' and 'very good', according to kappa) regarding deep myometrial invasion did not differ between the groups (experts, 34% vs gynecologists, 22%, P = 0.13), ultrasound experts assessed cervical stromal invasion with significantly greater interobserver reproducibility than did gynecologists (53% vs 14%, P < 0.001). Conclusion: Preoperative ultrasound assessment of deep myometrial and cervical stromal invasion in endometrial cancer is best performed by ultrasound experts, as, compared with gynecologists, they showed a greater degree of agreement with histopathology and greater interobserver reproducibility in the assessment of cervical stromal invasion.