Abstract
IMPORTANCE: Black women in the US with endometrial cancer (EC) are more likely to be diagnosed with advanced-stage disease independent of insured status and histologic type. The most common way of diagnosing EC at early stages is through screening of people with postmenopausal bleeding to detect endometrial thickness (ET). This approach may disproportionately underperform in Black women secondary to a higher prevalence of fibroids and nonendometrioid EC in this population, both of which affect the quality of ET measurement. OBJECTIVE: To compare the performance of recommended transvaginal ultrasonography (TVUS) ET thresholds as a screening method to prompt endometrial biopsy by race in a simulated cohort of symptomatic women. DESIGN, SETTING, AND PARTICIPANTS: In a simulated retrospective cohort study, based on data from Surveillance, Epidemiology, and End Results (SEER) national cancer registry 2012-2016; the US census; and published estimates of ET distribution and fibroid prevalence, diagnostic test characteristics of the 3-mm or more, 4-mm or more, and 5-mm or more ET thresholds for biopsy to capture EC diagnoses were calculated. The simulated cohort was constructed from February 2, 2020 (date of access to SEER data), to August 31, 2020. Analysis occurred from September 30, 2020, to March 30, 2021, including the primary analysis and the sensitivity calculations. MAIN OUTCOMES AND MEASURES: The main outcome measured was accuracy of the TVUS ET threshold to accurately identify cases of EC, measured by sensitivity, negative predictive value, and area under the curve (AUC). RESULTS: A total of 367 073 simulated Black and White women with postmenopausal bleeding were evaluated, including 36 708 with EC. Among Black women, the currently recommended 4-mm or greater ET threshold prompted biopsy for fewer than half of EC cases (sensitivity, 47.5%; 95% CI, 46.0%-49.0%); of women referred for biopsy, 13.1% were EC cases (positive predictive value, 13.1%; 95% CI, 12.5%-13.6%). The AUC for the 4-mm or more threshold was 0.57 (95% CI, 0.56-0.57). In contrast, among the White women, the 4-mm or more threshold led to biopsy for most with EC (sensitivity, 87.9%; 95% CI, 87.6%-88.3%). Of those referred for biopsy, 14.6% had EC (positive predictive value, 14.6%; 95% CI, 14.4%-14.7%); AUC was 0.73 (95% CI, 0.73-0.74). The same variations held for the 3-mm or more and 5-mm or more ET thresholds: sensitivity, positive predictive value, and AUC were consistently lower for Black women than White women. CONCLUSIONS AND RELEVANCE: The findings of this simulated cohort study suggest that use of ET as measured by TVUS to determine the need for EC diagnostic testing in symptomatic women may exacerbate racial disparities in EC stage at diagnosis. In simulated data, TVUS ET screening missed almost 5 times more cases of EC among Black women vs White women owing to the greater prevalence of fibroids and nonendometrioid histologic type in Black women.