Evaluating endometrial thickness for sonographic detection of neoplasia in diverse population of women

OBJECTIVE: This study aimed to compare the diagnostic performance of 3-mm, 4-mm, and 5-mm trans-vaginal ultrasound endometrial thickness thresholds for detecting endometrial neoplasia and to determine the optimal clinical cutoff. METHODS: In this prospective cohort study, 1170 women aged ≥50 years referred for endometrial evaluation between February 2014 and October 2020 were included, with follow-up through January 2021. All participants underwent trans-vaginal ultrasound performed by certified sonographers across 4 ultrasound units within a large academic medical center with an ethnically diverse patient population. Diagnostic accuracy measures (including sensitivity, specificity, positive predictive value, and negative predictive value) were calculated for each endometrial thickness threshold. The McNemar test was used to compare diagnostic performance across cutoffs. The main outcome was the detection of endometrial cancer or hyperplasia. RESULTS: Among the 1170 eligible women, 82 (7.0%) had endometrial cancer and 42 (3.6%) had hyperplasia. Analyses were limited to 975 cases with a clearly visualized endometrial stripe. Sensitivity for endometrial neoplasia detection was 100%, 97.8%, and 90.2% for the 3-, 4-, and 5-mm thresholds, respectively, while specificity was 9.5%, 16.1%, and 24.4%. Sensitivity and negative predictive value did not differ significantly between the 3- and 4-mm thresholds (p =.16 and p =.40); however, both metrics were significantly higher for the 3- and 4-mm thresholds compared with the 5-mm threshold (p =.005 and p =.01). The 4-mm cutoff demonstrated significantly higher specificity and positive predictive value compared with the 3-mm cutoff (p <.001). CONCLUSIONS: Both the 3-mm and 4-mm endometrial thickness thresholds provided excellent sensitivity for excluding endometrial neoplasia. The 4-mm cutoff achieved greater specificity, minimizing unnecessary invasive procedures, and may represent the optimal threshold for clinical application.