Objective: To determine the prevalence of endometrial thickening (endometrial thickness > 5 mm) in postmenopausal breast cancer patients taking tamoxifen.
Design: Cross-sectional descriptive study
Settings: Srinagarind Hospital, Faculty of Medicine, Khon Kaen University.
Subjects: Total of 37 postmenopausal breast cancer patients receiving 20-40 mg/day of tamoxifen treatment for at least 6 months were included in the study.
Method: Thorough history taking and physical examination as well as transvaginal ultrasonography (TVS) were conducted in all patients.
Results: Among the 37 patients included in this study, the mean age was 56.35 years. The mean body weight and mean body mass index was 60.88 kg and 26.03 kg/m2, respectively. The mean age at diagnosis of breast cancer was 51.84 years. The majority of patients (75.68%) had stage II disease while the rest of patients were diagnosed with stage III (16.22%), I (5.40%) and IV (2.70%), respectively. The mean + SD of endometrial thickness (ET) found in this study was 7.53 + 5.16 mm. The prevalence of thickened endometrium (defined as ET >5 mm from TVS) was 59.46%. Other pelvic pathologies detected by ultrasonography were multiple small hypoechogenic areas in the endometrium (32.43%), and myoma uteri (5.41%).
Conclusion: The prevalence of thickened endometrium in postmenopausal breast cancer patients taking tamoxifen found in this study was extraordinarily high. Therefore it seems to be justified to propose a transvaginal ultrasound screening in all postmenopausal breast cancer patients taking tamoxifen to detect endometrial thickening and possibly pathologies which could be resulted from tamoxifen treatment

Keywords: Tamoxifen, Postmenopause women, Breast cancer