Tamoxifen is widely used for endocrine treatment and
breast cancer prevention. It acts as both an
estrogen antagonist in breast tissue and an
estrogen agonist in the female lower genital tract.
Tamoxifen causes severe gynecologic side effects, such as
endometrial cancer. This review focuses on the effects of prolonged
tamoxifen treatment on the human female genital tract and considers its tumorigenicity in the gynecologic organs through clinical data analysis.
Tamoxifen is associated with an increased incidence of benign endometrial lesions such as
polyps and
hyperplasia and a two- to four-fold increased risk of
endometrial cancer in postmenopausal patients. Moreover, the incidence of functional
ovarian cysts is significantly high in premenopausal
tamoxifen users. To prevent
tamoxifen from having severe side effects in gynecologic organs, frequent gynecological examination should be performed for both premenopausal and postmenopausal patients with
breast cancer who are treated with this
drug.