Long-term effects of the levonorgestrel-releasing intrauterine system on serum lipids and the endometrium in breast cancer patients taking tamoxifen.

Objective: To investigate the long-term effects of a levonorgestrel-releasing intrauterine system on the endometrium and lipid profile of breast cancer patients taking tamoxifen.

Study Design: A total of 142 postmenopausal women taking tamoxifen were included in the study. A levonorgestrel-releasing intrauterine system was fitted to 70 women in the study group; a further 72 women acted as the control group.