clinical trial results looking at lipid levels in those who took letrozole after 5 yr
 

of tamoxifen recommends measuring lipid levels periodically

Clinical Trial
Lipid concentrations in postmenopausal women on letrozole after 5 years of tamoxifen: an NCIC CTG MA.17 sub-study
Kishor M. Wasan1 , Paul E. Goss2, P. Haydn Pritchard3, Lois Shepherd4, Dongsheng Tu4 and James N. Ingle5
(1)
Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
(2)
Massachusetts General Hospital Cancer Center, 55 Fruit Street, Cox Building, Room 640, Boston, MA 02114, USA
(3)
Healthy Heart Program, St. Paul’s Hospital, Vancouver, BC, Canada
(4)
Clinical Trials Group, National Cancer Institute of Canada, Queen’s Cancer Research Institute, Queen’s University, Kingston, ON, K7L 3N6, Canada
(5)
Mayo Clinic, Rochester, MN, USA


Kishor M. Wasan
Email: Kishor.Wasan@ubc.ca
Received: 8 October 2012Accepted: 10 October 2012Published online: 23 October 2012
Abstract
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 < 0.0001). 103 (56 %) women in the study had clinically significantly elevated levels of Lp(a) (106 % above baseline) after 5 years of therapy. The results were similar after excluding the 21 % of patients who had ever received anti-lipid treatment. Significant increases in total cholesterol, HDL cholesterol, LDL cholesterol, and, most notably, Lp(a) in postmenopausal women were observed following 5 years of adjuvant letrozole treatment and after 5 years of tamoxifen therapy and such patients should have monitoring of their lipid levels in clinical practice.
Keywords
Letrozole Serum lipids Primary breast cancer Tamoxifen Postmenopausal women 5-year follow-up