301P - Changes in lipid-levels following aromatase inhibitor treatment in early postmenopausal breast cancer

Background

There is an unsettled concern that treatment with aromatase inhibitors (AIT) may adversely affect lipid-levels. In the light of the improved breast cancer survival and increased risk of atherosclerotic cardiovascular disease in older people, unfavorable effects on lipid-levels may represent a significant health concern for this group of patients.

Methods

We linked data from nationwide health care databases, including a clinical breast cancer database with information about allocated and dispensed aromatase inhibitor treatment (AIT), 2009 to 2020, to identify a nationwide cohort of postmenopausal women with early breast cancer who had at least one low-density lipoprotein cholesterol (LDL-C)-measurement before and one after breast cancer diagnosis. We defined women who were allocated to and had AIT dispensed as exposed and women who were not allocated to and did not have AIT dispensed as unexposed. We used a linear mixed-effect model to estimate the difference in LDL-cholesterol-change (from before to after breast cancer diagnosis) according to AIT with adjustment for demographic characteristics, tumor characteristics and other anti-cancer treatments.

Results

Among 10,478 women, there were 22,722 pre-breast cancer LDL-cholesterol measurements and 42,820 post-breast cancer LDL-cholesterol measurements. Overall, 7927 of the women were exposed to AIT and 2551 women were unexposed. For AIT exposed, the LDL-cholesterol-change was -0.16 mM, and for unexposed, -0.14 mM, respectively. The corresponding adjusted difference in LDL-cholesterol-change for AIT exposed versus unexposed was -0.03 mM (95% CI -0.07 to 0.00). We found similar results in analysis of secondary outcomes.

Conclusions

This nationwide study does not support the concern that AIT adversely affects lipid-levels.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

Statens Serum Institut.

Funding

The study was supported both by foundations that received and did not receive funding from commercial companies (grants from Kræftens Bekæmpelse, Fonden til Lægevidenskabens Fremme, Aase og Ejnar Danielsens Fond, Helsefonden and Læge Sofus Carl Emil Friis og Hustru Olga Doris Friis' Legat and Intramural funds at Bispebjerg and Frederiksberg Hospital). None of the funding sources had any involvement in data collection, analysis or interpretation or in decision to submit the manuscript for publication. None have been paid to write the article.

Disclosure

M. Jensen: Other, Personal, Advisory Board, outside the submitted work: Novartis. B. Ejlertsen: Other, Institutional, Funding, outside the submitted work: Kræftens Bekæmpelse, AstraZeneca, Daiichi Sankyo, Eli Lilly, MSD, Novartis, Pfizer; Other, Institutional, Other, travel grant, outside the submitted work: Daiichi Sankyo, MSD, Pfizer; Other, Personal, Advisory Board, without payment, outside the submitted work: Eli Lilly. L. Køber: Other, Institutional, Other, speakers honorarium, unrelated to this manuscript: AstraZeneca, Boehringer, Novartis, Novo. All other authors have declared no conflicts of interest.