Modification of ultrasonographically measured endometrial thickness after discontinuation of adjuvant therapy with tamoxifen in postmenopausal breast cancer patients

Introduction: The aim of this study was to evaluate endometrial changes after five years of tamoxifen treatment by measuring endometrial thickness with transvaginal ultrasonography. Materials and Methods: Fifty-five asymptomatic postmenopausal women who had assumed tamoxifen, 20 mg daily, for five years were controlled six months after discontinuation of the therapy. Of these 42 were followed-up at 12 months. Statistical analysis was performed using the analysis of variance for repeated measures and the Anova test; p <0.05 was considered statistically significant. Results: We found a significant reduction in endometrial thickness at six months (p = 0.0046) and at 12 months (p = 0.0003) but not between six and 12 months (p = 0.06). Conclusion: A statistically significant reduction in endometrial thickness after discontinuation of tamoxifen therapy was found. This can probably be attributed to the cessation of the estrogenic side-effects of tamoxifen therapy.