Combination of endometrial thickness and time since menopause in predicting endometrial cancer in women with postmenopausal bleeding.

PURPOSE: This study was conducted to assess the combination of endometrial thickness, as measured by transvaginal sonography, and time since menopause, in predicting the presence of endometrial cancer in women with postmenopausal bleeding.

METHODS: The study group consisted of 95 women with postmenopausal bleeding who underwent sonographic measurement of endometrial thickness followed by endometrial biopsy. No patient had ever received hormone replacement therapy.

RESULTS: The mean endometrial thickness was significantly lower in the absence of endometrial carcinoma (6.9 +/- 4.3 mm) than in its presence (13.5 +/- 7.7 mm) (p < 0.005). The incidence of endometrial carcinoma increased with increases in endometrial thickness and the number of years since menopause. No patient had carcinoma when the endometrium was less than 5 mm thick, but 18.5% did when the thickness exceeded 9 mm. The incidence of cancer was 2.6% in women who had undergone menopause less than 5 years earlier but was 21.4% in women who had undergone menopause more than 15 years prior. Multiple logistic regression analysis showed that time since menopause and endometrial thickness were statistically significant predictors of endometrial carcinoma.

CONCLUSIONS: Time since menopause and endometrial thickness together define cutoff points for the diagnostic biopsy of tissue samples for endometrial carcinoma; that is, within a particular time interval, sampling should not be performed if the thickness is below a given value. When using cutoff points of 6 mm of endometrial thickness for women experiencing menopause 5-15 years prior and 5 mm in those going through menopause 15 or more years prior, approximately 60% of invasive procedures may be avoided. In addition, models derived by multiple logistic regression can be used to calculate a patient's risk of cancer based on her age and endometrial thickness.