E1715. Tamoxifen Gynecologic Effects: An Imaging Findings Review in Breast Oncologic Patients
  1. Susana Lopes Rodrigues; Instituto Portugues de Oncologia Francisco Gentil
  2. João Santos; Instituto Portugues de Oncologia Francisco Gentil
  3. Daniela Barros; Hospital de Braga
  4. Hálio Rodrigues Duarte; Instituto Portugues de Oncologia Francisco Gentil
Tamoxifen citrate is a nonsteroidal antiestrogen agent widely used for the treatment of breast cancer and it results in a spectrum of abnormalities involving the genital tract, the most concerning being an increased incidence of endometrial cancer and uterine sarcoma. The most harmful effects are due to its proliferative activity on the endometrium, which may result in hyperplasia, polyps, carcinoma and sarcoma. The probability of these effects seems to be related with longer treatments, cumulative dose, metrorrhagia and the existence of the pretreatment endometrial lesions. Developing leiomyomas, ovarian cysts and adenomyosis are others side effects well described.

Educational Goals / Teaching Points
To review the spectrum of effects of tamoxifen on the female genital tract and to describe the respective imaging findings in women treated with tamoxifen therapy.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Transvaginal ultrasound (US) should be the first-line imaging modality for evaluation of the uterus and ovaries in asymptomatic women undergoing tamoxifen treatment. Most women undergoing tamoxifen treatment have a thicker endometrium. Ultrasound is sensitive but not specific for evaluating endometrial abnormalities. Hysterosonography is used to improve the ability to diagnose intrauterine pathologic conditions and to resolve discrepancies between endometrial thickening on transvaginal US images and non-diagnostic results at endometrial biopsy. Magnetic Resonance (MR) imaging has higher specificity than ultrasound in evaluating the uterus and it may be appropriate in patients with an equivocal or abnormal transvaginal US who are unable to undergo hysterosonography.

Knowledge of the radiological aspects of the gynecological effects of the tamoxifen therapy is crucial for the prompt diagnosis and adequate treatment of these patients. Therefore, radiologists must be familiar with the effects of tamoxifen on the genital tract and with the limitations of each imaging modality.