Endometrial thickness and cancer risk in asymptomatic postmenopausal women: Defining evidence-based cut-offs by systematic review and diagnostic meta-analysis.

Endometrial carcinoma (EC) is the sixth most common malignancy among women worldwide and predominantly affects postmenopausal individuals. Transvaginal ultrasonography (TVUS) provides a non-invasive method for assessing endometrial thickness (ET); however, the optimal ET threshold for guiding endometrial sampling in asymptomatic postmenopausal women remains controversial. Establishing evidence-based ET cut-offs is essential to balance early detection of premalignant and malignant lesions against unnecessary invasive procedures, patient anxiety and healthcare costs. The aim of the present study was to evaluate the risk of EC and atypical endometrial hyperplasia (AEH) across different TVUS-measured ET thresholds in asymptomatic postmenopausal women and to identify the ET cut-off that provides the most clinically appropriate balance between sensitivity and specificity. A systematic review and diagnostic test accuracy meta-analysis was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses of Diagnostic Test Accuracy Studies Standards for Reporting Diagnostic Accuracy guidelines. Comprehensive searches of PubMed, EMBASE, Scopus, Cochrane Library and gray literature sources were performed through June 2025. Studies enrolling asymptomatic postmenopausal women with TVUS-assessed ET and histopathological confirmation were included. A total of 20 studies comprising 9,193 women met the eligibility criteria. Pooled analyses included sensitivity, specificity, positive and negative likelihood ratios, diagnostic odds ratios and summary receiver operating characteristic (SROC) curves. Subgroup analyses were performed according to ET thresholds of 3.0-5.9, 6.0-9.9, 10.0-13.9 and ≥14.0 mm. An ET ≥3.0 mm was associated with a significantly increased risk of AEH or EC (risk ratio 3.84; 95% confidence interval 2.95-5.11). Lower ET thresholds (3.0-5.9 mm) demonstrated the highest pooled sensitivity (0.79) with acceptable specificity (0.71), whereas thresholds ≥14 mm demonstrated markedly reduced sensitivity (0.23) despite higher specificity (0.89). Intermediate thresholds showed favorable diagnostic accuracy but demonstrated greater variability across studies. SROC and ROC analyses suggested that an ET threshold of ~5 mm provides the most clinically pragmatic balance between sensitivity and specificity for guiding endometrial sampling in asymptomatic postmenopausal women. TVUS-measured ET is a clinically valuable predictor of EC and AEH in asymptomatic postmenopausal women. An ET threshold of ~5 mm appeared to provide the most appropriate balance between early detection and avoidance of unnecessary biopsies. Integration of ET assessment with clinical risk factors may further improve individualized patient management and prevention-oriented diagnostic strategies.