Expectant management as a primary approach for asymptomatic endometrial polyps: An ambispective cohort study.
To assess the natural history and safety of expectant management for sonographically benign endometrial polyps (EPs) in asymptomatic premenopausal and postmenopausal women, focusing on spontaneous regression, growth, abnormal uterine bleeding (AUB) onset, and malignancy risk. Ambispective cohort study including 298 asymptomatic women (62 premenopausal, 236 postmenopausal) with sonographically benign EPs evaluated between January 2017 and January 2023. Ultrasound data were prospectively collected during routine care according to IETA standards (scheduled follow-up at 3 and 9 months, then annually), while case inclusion was ascertained retrospectively. Outcomes included complete spontaneous regression, lesion growth, AUB onset, hysteroscopic excision, and histopathology when available. Time-to-event analyses and parsimonious Cox proportional hazards models were applied. Median follow-up was 11 months (IQR 6-24). Complete spontaneous regression occurred in 24/298 women (8.05%; 95% CI 5.2%-11.9%), more frequently in premenopausal than postmenopausal women (14.5% vs. 6.4%; log-rank p = 0.058). AUB developed in 26/298 women (8.7%; 95% CI 5.7%-12.6%). Hysteroscopic excision was performed in 90/298 cases (30.2%; 95% CI 25.1%-35.7%), with histology available for 96 lesions (32.2%). One carcinoma was identified (1/96; 1.04%; overall 1/298 = 0.34%). Larger baseline mean diameter (per 5 mm; adjusted HR 1.22, 95% CI 1.06-1.41) and higher vascularity (score ≥ 3 vs. ≤ 2; HR 1.85, 95% CI 1.10-3.11) independently predicted earlier excision. Expectant management of asymptomatic sonographically benign EPs appears safe with low observed malignancy among excised lesions. Structured ultrasound surveillance may reduce unnecessary surgery while enabling timely intervention.