Preoperative and postoperative pathology concordance in endometrial intraepithelial neoplasia: A retrospective cohort study

OBJECTIVE: To assess the concordance between pre- and postoperative pathology in patients with endometrial intraepithelial neoplasia (EIN) undergoing hysterectomy, and identify predictors of malignancy, including sampling method, progestin therapy, and surgical timing. METHODS: A retrospective cohort study was conducted at a tertiary care academic center in Montreal, Canada, from January 2010 to July 2023. Patients undergoing hysterectomy for EIN were included. Demographics, progestin therapy, sampling method, time from biopsy to surgery, operative details, and final pathology were collected. Logistic regression was used to identify factors associated with malignant or benign outcomes. RESULTS: A total of 319 patients were included; 76 received preoperative progestins (medicated group), and 243 did not (unmedicated group). Pathology concordance was 71.2% overall (72.8% unmedicated, 65.8% medicated). Malignancy was found in 11.6% (12.8% unmedicated, 7.9% medicated); benign pathology in 17.2% (14.4% unmedicated, 26.3% medicated). Sampling method was not associated with concordance. In progestin-naïve patients, lower body mass index (BMI) (odds ratio [OR] 2.91, 95% confidence interval [CI]: 1.18-7.13) and premenopausal status (OR 2.20, 95% CI: 1.06-4.58) were associated with benign pathology. In progestin-treated patients, older age (OR 1.10, 95% CI: 1.01-1.22) and menopausal hormone therapy use (OR 16.85, 95% CI: 1.85-218.46) predicted malignancy, while longer time to surgery was associated with benign pathology (OR 2.50, 95% CI: 1.04-6.41). CONCLUSION: Concordance between preoperative EIN diagnosis and final hysterectomy pathology was 65.8%-72.8%, depending on progestin therapy. These findings highlight the importance of personalized management strategies in patients with EIN, with attention to patient preference, their risk factors, and treatment response.