Women who have survived breast cancer can drink alcohol in moderation, new research indicates.
Overall, moderate drinking before or after a diagnosis of breast cancer doesn't seem to have a harmful impact on survival from breast cancer, the study found.
When researchers looked only at moderate drinking before a breast cancer diagnosis, it was linked with a 15 percent lower risk of dying from breast cancer compared to nondrinkers, said study author Polly Newcomb, head of the cancer prevention program at the Fred Hutchinson Cancer Research Center, in Seattle.
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 during the 11 years the women were followed.
Newcomb's team found an association, and not a cause-and-effect relationship, for moderate alcohol intake and survival.
The findings ''should be reassuring to women," said Newcomb, who is also a research professor at the University of Washington.
It is known that alcohol intake does increase the risk of getting breast cancer. "Our focus was on breast cancer survivors," Newcomb said, as they often wonder whether they should drink alcohol or not.
Newcomb evaluated nearly 23,000 women. All reported on their intake of alcohol before diagnosis, and about 5,000 reported on their intake after. The follow-up was just over a decade, on average.
The study was published April 8 in the Journal of Clinical Oncology.
Newcomb evaluated women participating a study of risk factors for breast cancer sponsored by the U.S. National Cancer Institute (NCI). It began in 1988. The smaller follow-up study of drinking habits after diagnosis included about 5,000 women and was conducted from 1998 to 2001.
Although the post-diagnosis sample of survivors was smaller, Newcomb said, those who participated were similar in terms of age and other characteristics than the non-responders from the bigger sample, suggesting the findings are credible.
During the follow-up period, 7,780 deaths occurred, including nearly 3,500 from breast cancer. Newcomb looked at deaths and alcohol habits.
Women who had three to six drinks a week -- considered moderate drinking -- before diagnosis had about a 15 percent lower risk of death from breast cancer than nondrinkers, she found.
What could explain the difference in alcohol's impact -- that it raises the risk of getting the disease but doesn't affect the overall survival? Alcohol intake is thought to raise the risk of getting breast cancer due to increases in estrogen production, Newcomb said. It could be the type of breast cancer most likely to be found among women who drink may simply be more responsive to therapies that reduce estrogen.
The new findings should be welcome news to women, said Dr. Laura Kruper, chief of the breast surgery service and co-director of the breast oncology program at the City of Hope Comprehensive Cancer Center, in Duarte, Calif. She was not involved with the new study.
She said her patients who have gone through breast cancer treatment often ask her if it's OK to have a glass of wine. Kruper typically says to go ahead, if they enjoy the glass of wine and have no reasons not to drink.
The new study, she said, supports other research about alcohol having a heart-protective effect. 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."
The study was funded by the NCI and Komen for the Cure.