Aromatase inhibitors (AIs) influence blood lipid profiles. However, relatively few studies have directly compared the treatment effects of steroidal and nonsteroidal AIs.
A prospective single-center cohort study was conducted to investigate the effects of steroidal and nonsteroidal AIs on lipid profiles during the first 24 months of endocrine therapy in hormone receptor-positive postmenopausal patients with early breast cancer. The primary endpoint was the cumulative incidence of lipid events, while the secondary endpoints were changes in lipid profiles and lipid event-free survival.
Comparison of the lipid profiles of the two groups showed that triglycerides (TGs) and total cholesterol (TC) levels were significantly higher in the nonsteroidal AI group over 24 months ( p < 0.05), whereas low-density lipoprotein cholesterol (LDL-C) was significantly higher only at 3 months ( p = 0.017) and 6 months ( p = 0.026). High-density lipoprotein cholesterol (HDL-C) was significantly lower in the steroidal group at all time points ( p < 0.05), except at 18 months ( p = 0.085). The cumulative incidence of lipid events in the steroidal and nonsteroidal groups at 24 months was 25.3% and 37.0%, respectively. Multivariate analysis results indicated that TG, LDL-C, and steroidal AIs were independently associated with blood lipid events.
This trial showed that a significantly higher cumulative incidence of lipid events occurred in the nonsteroidal AI group than in the steroidal AI group, which indicated that steroidal AIs exerted a protective effect against blood lipid events in postmenopausal women receiving an AI as adjuvant therapy for breast cancer.