Does Femara change red wine's effect on estrogen in the body?

I posed this question to my boss, a pharmacist, and an intern, at work one day. They graciously did research for me and also contacted the University of Montana Drug Information Service.

You see, I love a glass or two of red wine before dinner but the current advice from the American Cancer Society is to avoid alcohol altogether if you want to not raise the risk of breast cancer. I have estrogen-driven cancer so they are talking to me.

Now I have posted before about a study on mice that showned that a phytochemical in red wine has an anti-cancer effect. But does that finding cross over to humans? And could Femara counteract the increase estrogen circulating in the blood stream that happens when I drink a glass of wine?

Here is the answer from the Drug Information Service:

Thank you for your question regarding Femara (letrozole) and its ability to decrease red wine's effect on estrogen in the body.

Estrogen plays a large role in the human body, especially in female patients who have experienced breast cancer or other hormone sensitive cancer. The substances in red wine believed to have possible effects on estrogen and cancer are phytochemicals. Resveratrol is the phytochemical that has been studied the most. Letrozole is an aromatase inhibitor that is used to treat breast cancer, because it inhibits conversion of androgens to estrogens. Currently there are no published reports of a food-drug interaction between Letrozole and red wine or red wine extract.

Red wine is thought to be cardioprotective. However the data on its effects on breast cancer are conflicting, with some studies showing an increased risk and others showing a decreased risk. There have been no studies conducted with both red wine and letrozole, but there have been several studies conducted with red wine extract in animals. Studies in mice with over-expression of aromatase found that red and white wine have both in vivo and in vitro aromatase inhibitor activity. The studies used samples of several types of wine, including pinot noir, merlot, zinfandel, hardonnay and carbernet. Another study found that red and white wines only have estrogenic activity in mammalian cells, since the extracts had no effect on a yeast estrogen screen assay. These studies included all active components of wine, not just resveratol. Red wine has more aromatase inhibitor activity that white wine because the grape skin, where phytochemicals are primarily found, is removed when making white wine.

There is currently a study being conducted in healthy premenopausal women examining the effect of red and white wine on estrogen and progesterone levels. The results of this study will most likely not be published until late 2008 or early 2009.

The data regarding red wine, estrogen and Letrozole is limited at this time. The studies provide insufficient data to prove red wine's effectiveness as a chemoprotective agent. It is possible that the aromatase inhibitor activity of both agents could be additive; however there are no published reports of an interaction between Letrozole and red wine.

There you have it. No conclusive answer available and no study in process that is looking at Femara's ability to counteract the rise in estrogen level caused by drinking alcohol. Maybe some day we'll have the answer. I haven't quit drinking red wine but think twice about it each time I have a sip.