Sonographic evaluation of endothelial function in letrozole and tamoxifen users

Abstract 

Objectives

Studies have shown that women previously treated for breast cancer present fewer cardiovascular events, indicating a possible protective effect of tamoxifen treatment. The effects of these aromatase inhibitors on cardiovascular protection remain controversial. The aim of this study was to compare some cardiovascular risk markers among breast cancer survivors following treatment with tamoxifen group (TMXg), letrozole group (LTZg) or no endocrine treatment group (NETg).

Methods

A total of 103 breast cancer survivors: 35 using TMXg, 34 using letrozole group (LTZg) and 34 using no endocrine treatment group (NETg) were evaluated. Ultrasonographic evaluation of brachial artery flow-mediated dilation (FMD), carotid intima–media thickness (IMT) and stiffness index (β); blood total cholesterol, HDL and triglycerides were assessed.

Results

All three groups presented similar values of HDL and IMT. TMXg showed the lowest total cholesterol (219.29±36.31mg/dL vs. 250.59±38.37mg/dL vs. 245.09±35.35mg/dL; TMXg vs. LTZg vs. NETg, respectively; p<0.01—ANOVA), the highest triglycerides (139.34±41.82mg/dL vs. 111.35±28.22mg/dL vs. 122.09±33.42mg/dL; p<0.01), the highest FMD (6.32±2.33% vs. 4.10±2.06% vs. 4.66±2.52%; p<0.01) and the lowest stiffness index (β) (5.08±1.68 vs. 6.28±1.75 vs. 5.99±1.86; p=0.01). LTZg did not differ significantly from NETg on any evaluated parameter.

Conclusions

We did not observe any effect of LTZg on the evaluated cardiovascular risk parameters compared to NETg. As such, the observed difference on lipid values, stiffness index (β) and FMD between women receiving tamoxifen and letrozole might be best attributed to the beneficial effect of tamoxifen than to a detrimental effect of letrozole.

Keywords: Selective estrogen receptor modulators, Aromatase inhibitors, Breast cancer, Vasodilation