Rate of premalignant and malignant endometrial lesion in “low-risk” premenopausal women with abnormal uterine bleeding undergoing endometrial biopsy

OBJECTIVE: To determine the incidence of endometrial hyperplasia and endometrial cancer (EH/EC) in low-risk premenopausal women with abnormal uterine bleeding (AUB) undergoing endometrial biopsy and to build a predictive model that includes clinical variables for predicting EH/EC in these women. METHODS: This retrospective study was conducted between January 2015 and March 2020. All premenopausal women aged <55 years with AUB who underwent endometrial sampling during a specified time period were included. Data regarding baseline characteristics, sonographic findings, and histological reports were collected from patient record sheets. RESULTS: During the specified time period, 1,089 premenopausal women underwent endometrial biopsy for AUB. Complete data analysis was done for 1,084 women. Of the endometrial samples, 95.3% revealed benign pathology, whereas 4.7% of the samples had major endometrial pathology EH/EC. On step-wise logistic regression analysis, intermenstrual bleeding (IMB) (OR, 3.15), body mass index (BMI) >25 kg/m(2) (odds ratio [OR], 4.4705), age >40 years (OR, 1.14), endometrial thickness (ET) >13 mm (OR, 2.59), and hypothyroidism (OR, 1.35) were significantly associated with EH/ EC. Considering the pretest probability for an EH/EC of 4.7%, this prediction model with a likelihood ratio of 14.2% demonstrated a post-test probability of 41% in the presence of the above-mentioned variables. CONCLUSION: The risk of EH/EC was lower in low-risk premenopausal women with AUB. However, premenopausal women with IMB aged >40 years, hypothyroidism, BMI >25 kg/m(2), and thickened endometrium (ET >13 mm) are at high risk of EH/EC; therefore, endometrial biopsy should be considered early in their management plan.