The Impact of Fibroids and Histologic Subtype on the Performance of US Clinical Guidelines for the Diagnosis of Endometrial Cancer among Black Women

Objective: To assess the predicted performance of the American College of Obstetrics and Gynecology (ACOG)’s recommended endometrial thickness (ET) of ≥4mm via transvaginal ultrasound (TVUS) for a simulated cohort of US Black women with postmenopausal bleeding (PMB). Methods: We used endometrial cancer parameters from ET studies upon which guidelines are based, as well as documented population characteristics of US Black wom­en, to simulate a cohort of US Black women with PMB. Annual endometrial cancer (EC) prevalence overall and by histology type (I and II), history and current diagnosis of uterine fibroids, and visibility of endometria were estimated. Sensitivity analyses were performed to assess performance changes with quality of baseline parameters and impact of fibroids on ET visibility. Main Outcome Measures: Performance characteristics of 3+, 4+, and 5+mm ET thresholds were assessed including sensitiv­ity, specificity, positive predictive value (PPV), negative predictive value (NPV), Receiver Operator Characteristic (ROC) curves, and the area under the curve (AUC). Results: In the main model with the 4+mm recommended threshold, TVUS ET showed a sensitivity of 47.5% (95% CI: 46.0-49.0%); specificity of 64.9% (95% CI: 64.4-65.3%); PPV of 13.1% (95% CI: 12.5-13.6%); NPV of 91.7% (95% CI: 91.4-92.1%), and AUC of .57 (95% CI: .56-.57). Conclusions: Among a simulated cohort of US Black women, the recommended 4+mm ET threshold to trigger diagnostic biopsy for EC diagnosis performed poorly, with more than 50% of cases missed and an 8-fold higher frequency of false nega­tive results than reported for the general population. Ethn Dis. 2021;30(4):543-552; doi:10.18865/ed.30.4.543