You may have heard that drinking alcohol is associated with a higher risk of breast cancer. Unfortunately, it's true: While the occasional glass of wine is fine, women who have an alcoholic drink every day are seven percent more likely to develop breast cancer than non-drinkers, and women who consume 2-3 drinks a day are 20 percent more likely to develop the disease. Breast cancer patients who drink are also at higher risk of a recurrence of the disease.
How Alcohol Triggers Breast Cancer Growth
Why does alcohol consumption have such an impact on the development of breast cancer? Researchers aren't sure, but a new study published in PLOS One suggests that the answer lies with the female sex hormone estrogen and the cancer-causing BRAF gene.
"Our research shows alcohol enhances the actions of estrogen in driving the growth of breast cancer cells," explains lead researcher Chin Yo Lin, PhD, assistant professor in the biology and biochemistry department at the University of Houston in Texas in a press release.
Estrogen can play a major role in the development (and treatment) of breast cancers. There are several different types of breast cancer. The most common are hormone receptor-positive breast cancers, which make up about two-thirds of all cases. In patients with these breast cancers, the hormones estrogen or progesterone (or both) can fuel cancer growth.
The study also showed that alcohol can make the drug tamoxifen, which is used to treat estrogen receptor-positive breast cancer that has spread to other parts of the body, less effective. Alcohol "diminishes the effects of the cancer drug tamoxifen on blocking estrogen by increasing the levels of a cancer-causing gene called BRAF," Lin added.
"It appears that alcohol increases expression of the cancer-causing BRAF gene and has an estrogen-like effect in the body, both of which increase breast cancer rates," says Stephanie Bernik, MD, a breast cancer specialist at Lenox Hill Hospital in New York City. While the press release notes that alcohol seems to encourage activity in the BRAF gene, "even in the absence of estrogen," Bernik notes, "It appears that alcohol is most likely to contribute to estrogen receptor-positive breast cancers."
What This Means for You
While the findings may sound alarming, the fact is that alcohol consumption is a modifiable risk factor for breast cancer—meaning it's one you can do something about, says Joseph A. Sparano, MD, chief of the Section on Breast Medical Oncology at the Montefiore Einstein Center for Cancer Care in New York City.
Alcohol consumption is just one of four modifiable risk factors for breast cancer. Here's what you can do to lower your risk:
- Get Moving. "Exercise can be protective," Sparano says. The 2008 Physical Activity Guidelines for Americans recommends getting at least 2.5 hours of moderate intensity physical activity every week.
- Limit Your Alcohol Intake. Women should consume no more than one drink a day, according to the American Cancer Society. One drink is 12 ounces of beer, 5 ounces of wine, or 1.5 ounces of hard liquor. "Abstinence would be ideal, but isn’t always possible," Bernik admits.
- Eat Right. "Eating a healthy diet has been shown to be helpful," Bernik adds. A healthy diet means plenty of fruits and vegetables, whole grains and dairy; lean sources of protein, and limited amounts of saturated and trans fat, salt, and added sugars, according to the Academy of Nutrition and Dietetics.
- Stay Within a Healthy Weight Range. "Obesity can predispose a woman to breast cancer risk or recurrence of breast cancer," Sparano points out.
A Special Warning for Breast Cancer Patients
If you've been diagnosed with breast cancer, avoid estrogen replacement therapy (a form of hormone replacement therapy, or HRT), advises Candy Arentz, MD, a breast surgical oncologist at Houston Methodist Hospital. Since estrogen can encourage the growth of breast cancer cells, it's best for patients to avoid adding the hormone after menopause.
Bernik says this new study could lead to further research on the relationship between alcohol and cancer. "Hopefully, it will also provide women with information that allows them to make choices regarding how much alcohol they consume," she concludes.
Stephanie Bernik, MD, reviewed this article.
Sources
Candy Arentz, MD. Email interview on May 10, 2016.
Stephanie Bernik, MD. Email interview on May 3, 2016.
Joseph A. Sparano, MD. Email interview on May 6, 2016.
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