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Aromatase Inhibitors Tied to Endothelial Dysfunction in Older Women

December 12, 2016

By Megan Brooks

NEW YORK (Reuters Health) - A small study shows an association between aromatase inhibitor (AI) therapy and endothelial dysfunction in postmenopausal women with breast cancer.

The study was featured December 8 at a press briefing at the 2016 San Antonio Breast Cancer Symposium.

"With a growing number of cancer survivors, it is very important that we look to understand the long-term complications from cancer treatment. Most women with early-stage breast cancer are at greater risk of dying from cardiovascular disease than their breast cancer," Dr. Anne Blaes of the University of Minnesota explained in a conference statement.

"The development of cardiovascular disease is a multistep process, and the cardiovascular risk of AIs has always been a concern," she noted.

Dr. Blaes and colleagues assessed endothelial function in 25 healthy postmenopausal women and 36 postmenopausal women with locally advanced breast cancer prescribed an AI. The vast majority of the women were white and had no personal history of heart disease.

The women with breast cancer had a mean age of 61, BMI of 27 and mean systolic blood pressure of 128.6 mmHg. The control women were slightly younger (mean age, 59) with a BMI of 26 and mean systolic BP 116 mmHg. None of the women had a history of tobacco use, hypertension, or hyperlipidemia.

Most of the breast cancer patients had stage 1 or 2 cancer, about half received chemotherapy and two-thirds received radiation. Most were on anastrazole or letrozole. Seven of the 36 had a history of tamoxifen use.

On EndoPAT testing, women on AI therapy had lower median large-artery elasticity (12.9 vs. 14.6 ml/mmHg, P=0.12) and small-artery elasticity (5.2 vs. 7.0 ml/mmHg, P=0.07), and significantly reduced endothelial function (P<0.0001), even after accounting for differences in blood pressure, Dr. Blaes reported. The EndoPAT ratio was 0.8 in AI-treated women compared to 2.7 in controls.

Endothelial dysfunction using EndoPAT has been associated with an increased risk of cardiac events, independent of Framingham risk score, Dr. Blaes noted in her presentation.

There was no correlation between the use of chemotherapy, radiation therapy, type of AI, or duration of AI use and the reductions observed in endothelial function.

Dr. Blaes cautioned that the study was small and needs to be replicated.

Nonetheless, she said it hints that postmenopausal women with breast cancer on AI therapy have reduced endothelial function, which is a "predictor of adverse cardiovascular disease. This is independent of the duration of AI use compared to normal healthy postmenopausal women."

"With the growing trend that longer duration of endocrine therapy is needed, further work is needed to confirm these findings," she concluded.

The study had no commercial funding and the authors have disclosed no conflicts of interest.


San Antonio Breast Cancer Symposium 2016.

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