The effect of tamoxifen therapy on the endometrium and ovarian cyst formation in patients with breast cancer.

Objective: To evaluate the effect of tamoxifen on female reproductive organs in women with breast cancer.

Methods: We retrospectively reviewed the medical records of 309 women with breast cancer who were currently receiving tamoxifen and undergoing regular gynecological examination.

Results: We evaluated 92 pre- and 217 postmenopausal women. The prevalence of endometrial thickening was 12% in the pre- and 10.6% in the postmenopausal group. An endometrial biopsy was performed in 43 women and confirmed endometrial cancer in 1, endometrial polyps in 14, and endometrial hyperplasia in 4 women. Transvaginal ultrasonography showed 25 cases of newly developed ovarian cysts. Most ovarian cysts had disappeared during follow-up.

Conclusion: Tamoxifen use in women with breast cancer causes few complications and is considered safe for female reproductive organs in case of regular gynecological examination.