Endometrial assessment by vaginal ultrasonography might reduce endometrial sampling in patients with postmenopausal bleeding: a prospective study.

The purpose of this study is to compare transvaginal sonographic endometrial assessment with histology obtained by endometrial curettage in postmenopausal patients and to determine a cut-off point for endometrial thickness to reduce unnecessary diagnostic curettage for postmenopausal bleeding. A total number of 289 postmenopausal women were studied prospectively; 192 patients with postmenopausal bleeding and 97 postmenopausal women without bleeding comprised the study and control groups respectively. All patients were scanned by ultrasound transvaginally, then dilatation and curettage was performed for endometrial evaluation. In all women with and without postmenopausal bleeding, endometrial thickness of 4 mm or less as depicted by sonography correlated well with 'atrophic endometrium' (100%). Of 158 women with an endometrium > 4 mm in both groups, 40 women (25.1%) had a negative result (tissue insufficient for diagnosis or atrophic endometrium), while 118 patients (74.8%) had a positive result which included proliferative and secretory endometrium, endometrial hyperplasia, polyps and cancer. As the endometrial thickness increased, the probability of finding pathology with curettage was increased linearly in postmenopausal bleeding (PMB) positive and negative groups and there was a significant linear positive correlation between PMB (+) and (-) cases (Linear regression, R = 0.91, p < 0.03). A significant difference was found between endometrium carcinoma and all other endometrial pathologies concerning the mean endometrial thickness of 22.7 +/- 10.2 mm (chi-square, p < 0.0001). Also, the mean endometrial thickness of 4.7 +/- 3.3 mm for atrophic endometrium and 6.1 +/- 3.7 mm for 'tissue insufficient for histological diagnosis' were found significantly different than all other endometrial pathologies (chi-square, p < 0.0001). Endometrial thickness of < or = 4 mm may serve as cut-off point for predicting pathology negative cases with an accuracy of 100% in postmenopausal bleeding positive and negative cases. Then as the endometrial thickness increases, the probability of finding endometrial pathology in curettage increases linearly with a positive predictive value of 74.6%.