Endometrial thickness in Tamoxifen-treated patients: An independent predictor of endometrial disease

Objective: To assess the independent contribution of transvaginal ultrasoun d in identifying women at risk for endometrial disorders, and determine whe ther a cutoff value identifies women who need endometrial histologic assess ment. Methods: Postmenopausal women with breast cancer who were receiving tamoxif en, with ultrasonographic endometrial thickness greater than 4 mm or vagina l bleeding, had hysteroscopy with selective endometrial biopsies. Endometri al thickness, duration of tamoxifen therapy, and endometrial histology were studied. Parametric and nonparametric tests and logistic regression and re ceiver operating characteristic curves were used for statistical analysis. Results: The study population consisted of 163 women, 46 with vaginal bleed ing. The proportion of women with abnormal histologic findings was greater among those with endometrial thicknesses exceeding 9 mm compared with those with endometrial thicknesses 9 mm or less (60% versus 6.1%, P < .001) and among women who received tamoxifen for more than 27 months than those who r eceived it for less time (46% versus 16%, P < .005). Logistic regression sh owed that endometrial thickness greater than 9 mm and vaginal bleeding were independent predictors of abnormal findings at hysteroscopy. Conclusion: In women taking tamoxifen, sonographic endometrial thickness ex ceeding 9 mm and the presence of vaginal bleeding are independent predictor s of endometrial disease. If either exists, hysteroscopy and biopsy should be done. (Obstet Gynecol 1999;93:1004-8. (C) 1999 by The American College o f Obstetricians and Gynecologists.).