Predictive Value of Preoperative Endometrial Thickness for Concurrent Endometrial Carcinoma in Patients with Endometrial Intraepithelial Neoplasia.

Objective. Endometrial intraepithelial neoplasia (EIN) is a premalignant lesion associated with a substantial risk of concurrent endometrial carcinoma. This study aimed to evaluate whether preoperative endometrial thickness measured by transvaginal ultrasonography could predict concurrent endometrial carcinoma in patients diagnosed with EIN. Methods. This retrospective study included 102 patients diagnosed with EIN on endometrial sampling who subsequently underwent hysterectomy. Demographic and clinical data and preoperative endometrial thickness were collected, and final histopathology after hysterectomy was recorded. Receiver operating characteristic (ROC) curve analysis and multivariable logistic regression were performed. Results. The median endometrial thickness was 13 mm (range 4-45), and most patients were postmenopausal (68.6%). Final pathology revealed endometrial carcinoma in 50 patients (49.0%) and persistent EIN in 52 (51.0%). Endometrial thickness significantly predicted concurrent carcinoma (AUC 0.679, 95% CI 0.575-0.784; p = 0.002), with an optimal cut-off of 14.5 mm (sensitivity 58.0%, specificity 75.0%). Carcinoma was found in 69.0% of patients with thickness ≥ 14.5 mm versus 35.0% below this value (p < 0.001). On multivariable analysis, endometrial thickness (OR 1.15 per mm; 95% CI 1.05-1.24; p = 0.001) and age (OR 1.11; 95% CI 1.02-1.19; p = 0.007) were independently associated with concurrent carcinoma. Conclusions. Preoperative endometrial thickness is independently associated with concurrent endometrial carcinoma in patients diagnosed with EIN. A thickness of 14.5 mm or greater may indicate a higher risk of malignancy; however, given its moderate diagnostic accuracy, it should complement rather than replace a comprehensive preoperative assessment.