A recent study published in the Journal of Clinical Oncology in July lends further support to the strategy of minimal surveillance for asymptomatic women. In addition, some women received hysteroscopy. The vast majority of women were postmenopausal. All women were asymptomatic, meaning that they had no gynecologic complaints and no uterine bleeding. Endometrial thickening greater than 5mm was considered abnormal, and these women were advised to undergo hysteroscopy.
Tamoxifen is associated with endometrial thickening by transvaginal ultrasound.
Women not on tamoxifen had a median thickness of 2.5mm, in contrast to a median endometrial thickness of 7.3mm for those on tamoxifen. Endometrial thickness increased as a function of time on tamoxifen, from 4.5mm for those treated from 0-2 years to 10.8mm for those on tamoxifen for 10 years or more. Women with endometrial thickening were referred for hysteroscopy. Thus, transvaginal ultrasound is associated with a high false-positive rate among women on tamoxifen, making it a poor screening tool. All women on tamoxifen should receive annual gynecologic exams, and any woman with abnormal bleeding merits thorough evaluation, including endometrial biopsy.