Should ultrasound assessment of the endometrium be necessary in patients treated with Tamoxifen?

Tamoxifen is a nonsteroidal selective estrogen receptor modulator that is used mainly for adjuvant treatment of estrogen receptor-positive breast cancer. However, tamoxifen, due to its estrogen-mimicking effects, has been linked to various uterine conditions including menstrual irregularities, and endometrial cancer. Considering that in women taking tamoxifen, ultrasonographical endometrial thickness can be increased without an underlying pathology and that the tamoxifen induces only an extra endometrial cancer in 1 per 1000 women per year of use, patients undergoing tamoxifen treatment don't typically undergo regular examinations of the endometrium, including ultrasonography. Routine ultrasonographic screening for endometrial lesions could result in excessive intervention for non-symptomatic endometrial conditions, undue stress, and might even negatively affect patients' adherence to tamoxifen therapy, which is crucial for reducing breast cancer recurrence and mortality. Nevertheless, if any unusual bleeding arises, an endometrial evaluation is necessary.