Alcohol Consumption Good for Breast Cancer Survivors?
Researchers have found that drinking alcohol increases ones risk of developing breast cancer, but a new study has found that drinking before and after diagnosis does not impact survival from the disease. In fact, a modest survival benefit was found in women who were moderate drinkers before and after diagnosis due to a reduced risk of dying from cardiovascular disease, a major cause of mortality among breast cancer survivors.
“Our findings should be reassuring to women who have breast cancer because their past experience consuming alcohol will not impact their survival after diagnosis,” study leader Polly Newcomb, Ph.D., a member of the Public Health Sciences Division and head of the Cancer Prevention Program at Fred Hutchinson Cancer Research Center, was quoted as saying. “This study also provides additional support for the beneficial effect of moderate alcohol consumption with respect to cardiovascular disease.”
The study was based on data from almost 23,000 women who participated in the Collaborative Breast Cancer Study, a National Cancer Institute-sponsored, multi-site, population-based study of risk factors for breast cancer. The study began in 1988 and was conducted in New Hampshire, Massachusetts and Wisconsin. In a smaller follow-up study between 1998 and 2001, about 5,000 participants were sent a follow-up questionnaire about their alcohol consumption habits after diagnosis.
Among study participants with a history of breast cancer, the authors found that the amount and type of alcohol a woman reported consuming in the years before her diagnosis was not associated with her likelihood from dying from breast cancer. However, the authors also found that those who consumed a moderate level of alcohol (three to six drinks per week) in the years before their cancer diagnosis were 15 percent less likely to die from cardiovascular disease than non-drinkers. Moderate wine consumption in particular was associated with a lower risk of cardiovascular disease mortality, while no such benefit was evident for consumption of beer or spirits, or for heavier levels of alcohol consumption.
Alcohol consumption can contribute to many different adverse health effects, but probably the most researched and documented is alcohol’s effect on the risk of developing breast cancer.
There are dozens of research studies that have shown again and again that women who drink alcohol have a greater chance of developing breast cancer than those who do not drink, and neither the type of alcohol consumed nor even the frequency of drinking changes the risks involved.
Alcohol Is a Carcinogen
Since May 2000, alcohol has been listed as a known human carcinogen by the U.S. Department of Health and Human Services in its “9th Report on Carcinogens - Review of Substances for Listing/Delisting” and has been found to contribute to an increased risk of many different types of cancers.
But for women, breast cancer is the most common cancer with an estimated one in every nine females at risk to develop the disease at some point in their lifetime.
Daily Drinkers at Risk
Women at the greatest risk for breast cancer are those who have a family history of the disease. And for those women, drinking alcohol significantly increases that risk.
A Mayo Clinic study of 9,032 women found that women who had close relatives with breast cancer and were daily drinkers had double the risk of breast cancer compared to those who never drank. There is other research that indicates that drinking alcohol increases the risk of breast cancer even for those who do not have a family history.
Similar patterns were evident when considering reported alcohol consumption after breast cancer diagnosis. The amount and type of alcohol a woman consumed after diagnosis did not appear to be associated with survival of breast cancer, but those who consumed alcohol in moderation experienced a 39- to 50-percent lower mortality rate from cardiovascular disease.
Increased Risk for Breast Cancer Recurrence
For women who have already been diagnosed with breast cancer and who are cancer survivors, drinking alcohol is also a threat. A Life After Cancer Epidemiology study of 1,897 women found that drinking a few as three to four drinks a week can increase the risk of breast cancer recurrence.
A family history of breast cancer is not the only factor that plays a role in a woman’s risk of developing breast cancer. Other risks include early puberty, late menopause, delaying childbirth until late in life, or not having children at all.
If you have any of those risk factors, and/or if you are postmenopausal, and/or if you do have a family history of breast cancer, you can significantly reduce your risk by reducing your alcohol consumption or not drinking at all.
What could account for the difference in alcohol’s impact on developing breast cancer risk and on survival from the disease? “It could be that the kind of breast cancer that is more likely to be diagnosed among women who drink may be more responsive to hormone-reduction therapies,” Newcomb said. Alcohol consumption is believed to influence breast cancer risk through increases in estrogen production in both pre- and post-menopausal women.
Rodríguez-Fragoso, professor of pharmacology and toxicology at the Universidad Autonoma del Estado de Morelos in Mexico, presented her group’s work at the annual meeting of the American Society for Biochemistry and Molecular Biology, held in conjunction with the Experimental Biology 2012 conference in San Diego on April 23.
Alcohol consumption has long been established as a risk factor for breast cancer. But finding the direct link that makes it so has so far proved elusive. Now, Rodríguez-Fragoso and her collaborators think that they have found the answer, a protein called CYP2E1.
“We knew that CYP2E1 could break down ethanol and that doing so created unstable, highly reactive chemicals known as free radicals,” she says. Working with researcher Scott Burchiel and his group at the University of New Mexico, Rodríguez-Fragoso’s team had previously found that free radicals were associated with activation of cellular mechanisms that lead to tumor development. “The question then was, does having more CYP2E1 make you more susceptible to ethanol-induced toxicity, thereby increasing your risk of developing cancer?”
CYP2E1 is found in breast cells known as mammary epithelial cells, which are also where most breast cancers originate, suggesting to the researchers that CYP2E1 may be involved in breast cancer development. To test this hypothesis, the researchers administered ethanol to separate cultures of mammary epithelial cells that had varying levels of CYP2E1. Cells that expressed low levels of CYP2E1 were mostly immune to the effects of the ethanol treatment; however, cells with increased amounts of CYP2E1 protein were greatly affected, suggesting that women with higher expression levels of the protein would show similar responses.
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SOURCE: Journal of Clinical Oncology, April, 2013