The Effect of Exemestane on the Lipidemic Profile of Postmenopausal Early Breast Cancer Patients: Preliminary Results of the TEAM Greek Sub-study

Abstract

Long-term endocrine therapy for breast cancer may have clinical implications as drugs that potentially alter the lipid profile may increase the risk of developing cardiovascular disease. In this study, a companion sub-protocol to the TEAM (Tamoxifen and Exemestane Adjuvant Multicenter) International trial, we compared the effect of the steroidal aromatase inactivator exemestane on the lipid profile of postmenopausal women with early breast cancer in the adjuvant setting to that of tamoxifen. In this open-label, randomized, parallel group study, 176 postmenopausal patients with estrogen and/or progesterone receptor positive early breast cancer were randomized to either adjuvant exemestane (25 mg/day; n = 90) or tamoxifen (20 mg/day; n = 86). Assessments of total cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL) and serum triglycerides (TRG) were performed at baseline and every 3 months for the first 12 months. Serum triglyceride levels were consistently increased above baseline throughout the study in the tamoxifen arm, while there was a trend towards reduction in the exemestane arm. There was also an overall trend for tamoxifen to decrease the levels of LDL throughout the study period. Exemestane did not demonstrate any other significant change in HDL levels; however, there was a consistent trend for a reduction in total cholesterol in both treatment arms. The atherogenic risk determined by the TC:HDL ratio remained stable in both arms throughout the treatment period. Exemestane appears to have a neutral effect on total cholesterol and HDL levels. Unlike tamoxifen's positive effect on LDL levels, exemestane does not significantly alter LDL levels. Tamoxifen on the other hand increases triglyceride levels, while exemestane results in a beneficial reduction in TRG levels. These data offer additional information with regard to the safety and tolerability of exemestane in postmenopausal breast cancer patients and support further investigation of its potential usefulness in the adjuvant setting.