Lipid concentrations in postmenopausal women on letrozole after 5 years of tamoxifen: an NCIC CTG MA.17 sub-study

To evaluate changes in serum lipid parameters (cholesterol, HDL cholesterol, LDL cholesterol, triglycerides, and lipoprotein(a) [Lp(a)]), in postmenopausal women receiving letrozole after tamoxifen therapy. MA.17L is a sub-study of MA.17, a double-blind, placebo-controlled trial of extended adjuvant letrozole. Eligible postmenopausal women were non-hyperlipidemic and not on lipid-lowering drugs. This analysis considers the 183 patients on the letrozole arm. Lipid parameters evaluated at baseline, 6 months, 12 months, and yearly thereafter until completion of 5 years of letrozole. The median duration of letrozole treatment was 5.0 years with a range from 0.03 to 6.05 years. After 5 year tamoxifen, patients on letrozole experienced significant increases from baseline in total cholesterol, LDL cholesterol, and Lp(a) at all study time points but no statistically significant changes in triglycerides. Specifically, a statistically significant increase was found at 60 months in total cholesterol [mean percentage change from baseline (PC) 5.27; p = 0.003], HDL cholesterol (mean PC 6.75; p = 0.003), LDL cholesterol (mean PC 10.02; p = 0.001), Lp(a) (mean PC 105.95; p