Source: DGNews  |  Posted 2 years ago

By Ed Susman

SAN ANTONIO, Tex -- December 14, 2009 -- Postmenopausal women with
oestrogen-positive breast cancer who are treated with exemestane appear to have
more unfavourable changes in lipid profiles than women treated with other
aromatase-inhibiting drugs such as letrozole and anastrozole, researchers said
here at the 32nd Annual San Antonio Breast Cancer Symposium (SABCS).

“If you were treating a [woman] with a high risk of cardiac disease, you might
not want to use exemestane,” said Fiona McCaig, MD, Breakthrough Breast Unit,
Western General Hospital, Edinburgh, Scotland, United Kingdom.

During her poster presentation on December 12, Dr. McCaig said that when women
were treated with aromatase inhibitors, there were significant changes in lipid
profiles -- particularly in cholesterol and triglyceride levels.

Dr. McCaig and colleagues recruited 120 women diagnosed with invasive breast
cancer into an open-label trial and assigned 34 to receive anastrozole 1 mg a
day; another 34 women to receive letrozole 2.5 mg a day; and 49 women to
receive exemestane 25 mg a day.

Lipid levels were analysed at baseline, after 3 months of treatment, and after
4 months of treatment. All patients were then switched to tamoxifen, and lipid
levels were checked at 12 months.

Exemestane reduced baseline triglycerides by 11.53% compared with a 3.91%
decrease with anastrozole and a 2.29% increase with letrozole, Dr. McCaig noted
at her presentation. The difference between exemestane and the other aromatase
inhibitors was significant (P = .04).

Total cholesterol dropped 5.48% with exemestane and fell 5.32% with
anastrozole. It increased 0.15% with letrozole (P = .31).

Low-density lipoprotein cholesterol decreased 1.30% with exemestane, 6.42% with
anastrozole, and 0.72% with letrozole (P = .50).

High-density lipoprotein (HDL) cholesterol decreased 7.90% with exemestane,
1.67% with anastrozole, and 0.37% with letrozole (P = .20).

The total cholesterol to HDL cholesterol ratio increased 4.7% with exemestane
(P = .01) when compared with a decrease of 2.85% with exemestane and
a 0.47% increase with letrozole.

“As expected, all the lipid values were improved when the patients were
switched to tamoxifen,” Dr. McCaig said. HDL cholesterol, for example,
increased by 15.52% among the women who had been taking exemestane, but only
increased 0.59% with anastrozole and 1.89% with letrozole.

“These results support previous studies suggesting that exemestane has negative
impact on lipid levels and may potentially increase cardiovascular risk,” Dr.
McCaig said. “However, changes in metabolic parameters could be managed with
appropriate medications if necessary. This has important implications in the
safety of long-term aromatase inhibitor treatment.”

Funding for this study was provided by Novartis.

Presentation title: A Randomised Study Comparing the Effects of Adjuvant
Anastrozole (A), Letrozole (L) and Exemestane (E) on Lipid Metabolism. Abstract
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