April 11, 2013 | by Roberta Nichols
Numerous studies have connected the dots between alcohol consumption and breast cancer, but the impact on breast cancer survival has been less clear.
A new study suggests not only that breast cancer survivors can continue to drink alcohol in moderation, without fear of endangering their survival, but that moderate imbibing might produce an added survival benefit – a reduced risk of dying from cardiovascular disease. Because of the toxicity of some cancer treatments, heart disease is a major cause of mortality among breast cancer survivors.
"Women consuming moderate levels of alcohol, either before or after diagnosis, experienced better cardiovascular and overall survival than nondrinkers," wrote principal investigator Polly A. Newcomb, Ph.D., a member of the Public Health Sciences Division and head of the Cancer Prevention Program at Fred Hutchinson Cancer Research Center.
The findings were published April 8 in the Journal of Clinical Oncology.
An estimated 65 percent of women in the United States consume alcohol, and drinking is widely recognized as a breast-cancer risk. But researchers sought to examine the relationship between pre- and post-diagnosis drinking and mortality among breast cancer survivors.
"The health impact of alcohol consumption after a breast cancer diagnosis is salient for the 3 million breast cancer survivors in the U.S. today," wrote Newcomb in the study.
Although researchers found only an association between moderate alcohol intake (three to six drinks per week) and survival rather than a definitive cause-and-effect relationship, "our findings should be reassuring to women who have breast cancer because their past experience consuming alcohol will not impact their survival after diagnosis," said Newcomb. "This study also provides additional support for the beneficial effect of moderate alcohol consumption with respect to cardiovascular disease."
She and her colleagues analyzed data provided by women enrolled in the Collaborative Breast Cancer Study (CBCS), begun in 1988 as a multisite population-based case-control study of risk factors for breast cancer. Researchers examined pre- and post-diagnostic alcohol intake in a cohort of 22,890 women with breast cancer who lived in New Hampshire, Massachusetts and Wisconsin.
Subjects were between 20 and 79 when they were diagnosed between 1985 and 2006. All of the women said they had consumed alcohol prior to their diagnosis. In a smaller follow-up study between 1998 and 2001, 14,621 women were sent questionnaires about their drinking habits after diagnosis and 4,481were included in the analysis.
During the 11.32 years that the women were followed, researchers found that moderate drinkers before diagnosis had about a 15 percent lower risk of death from breast cancer compared to nondrinkers, Newcomb told Healthday. They also found that women who drank moderately before or after a breast cancer diagnosis had a 25 percent lower risk of death from cardiovascular disease and a 20 percent lower risk of death from other causes.
The kind of alcohol consumed mattered, researchers discovered. Moderate wine consumption was linked to a lower risk of cardiovascular disease mortality, a benefit not found for beer or spirits or for heavier levels of alcohol consumption.
What might explain the difference in alcohol’s effect on developing breast cancer and on surviving it? “It could be that the kind of breast cancer that is most likely to be diagnosed among women who drink may be more responsive to hormone-reduction therapies,” said Newcomb in a press release. Alcohol consumption is believed to influence breast cancer risk through increases in estrogen production in pre- and post-menopausal women.
In an accompanying Journal of Clinical Oncology editorial, Wendy Demark-Wahnefried, Ph.D., R.D., associate director for Cancer Prevention and Control at UAB Comprehensive Cancer Center, offered a sobering reminder.
Nondrinkers should not be encouraged to start drinking just because alcohol is associated with cardiovascular benefit, she warned. Women should keep in mind that alcohol is also associated with other dangers, such as accidental and violent death, chronic health conditions and psychosocial problems.
Breast cancer surgeon Laura Kruper, M.D., director of the Rita Cooper Finkel and J. William Finkel Women's Health Center at City of Hope, told Healthday that patients who have gone through breast cancer treatment often ask her if there is any harm in having a glass of wine.
Kruper, who was not involved in this study, typically tells them to proceed, if they enjoy a glass of wine and have no reasons not to drink.
The new study, she said, supports prior research about alcohol’s apparent ability to protect the heart.
The results seem to suggest that doctors can tell women, when it comes to moderate alcohol intake: "You don't have to radically change the way you live just because you have had breast cancer."
Visit City of Hope's website, for more information about City of Hope’s Women’s Cancers Program.