HR and breast cancer: In exploratory interaction analyses, among SHD users TAM+OFS versus TAM was associated with lower LDL-C and total cholesterol, whereas in AI+OFS versus TAM SHD use was associated with lower HDL-C.<h4>Conclusion</h4>In premenopausal women with HR+/HER2- breast cancer, AI+OFS was associated with an adverse lipid profile and a possible increase in carotid plaque compared with TAM-based regimens.