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

Abstract

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. All women were followed for 36 months. Serum lipids were measured at the beginning and at the end of 36 months. Endometrial biopsies were obtained by hysteroscopy at the beginning and at the end of the 36th month in both groups.

Results: After 36 months, there were minor changes in serum lipids, fewer endometrial polyps and no endometrial hyperplasia in the study group compared to the control group.

Conclusion: The levonorgestrel-releasing intrauterine system does not affect serum lipid levels significantly and may prevent the increased risk of endometrial polyps and hyperplasia associated with the use of tamoxifen in women with breast cancer. This may reduce the need for investigation of side-effects in women taking tamoxifen and also reduce patient discomfort while improving treatment adherence.