For women who beat breast cancer, one of their biggest fears is recurrence of the deadly disease. Now a study funded primarily by the National Cancer Institute is sounding a warning for breast cancer survivors about enjoying more than two glasses of wine a night. However, the lead author adds that the results do not necessarily mean women should give up alcohol altogether.
The study, being finalized now and peer reviewed for publication, looked at the drinking habits of women who survived breast cancer to see if their lifestyle decisions impact the chance of recurrence.
In past studies, alcohol consumption has been found to be associated with an increased risk of breast cancer, but its role in breast cancer survival is less clear.
The researchers examined data from 1,898 early-stage breast cancer survivors participating in the Life After Cancer Epidemiology Study, which gathered lifestyle information on women with the disease between 1997 and 2000.
In that study, a total of 275 breast cancer recurrences were diagnosed and 232 subsequent deaths recorded. By comparing the rate of recurrence to alcohol choices, the scientists found that consuming more than two drinks per day was equal to a nearly 39 percent greater risk. On top of that, for post-menopausal women the risk nearly doubled.
"It has been suggested that alcohol could increase the risk of breast cancer by increasing estrogen metabolism and circulating levels of estrogen, thus promoting growth of the tumor," said Dr. Marilyn Kwan, one of the study's authors and part of the division of research at Kaiser Permanente. "A similar mechanism might be responsible for increasing the risk of breast cancer recurrence."
Kwan also dismissed earlier studies that find that diets rich in folate, a compound found in leafy greens and legumes, may reduce the risk of breast cancer in moderate wine drinkers.
"We accounted for total folate consumption in our analysis by including this information as an adjustment factor," Kwan said, "but we still observed an increased risk of breast cancer recurrence with regular alcohol consumption."
Even though the study separates alcohol consumption by category, Kwan says that the study design does not allow for sweeping assumptions based on beverage choice.
"The majority [90 percent] of the women in our study who consumed alcohol, drank wine. Therefore, wine drinkers were the largest category," she said. "Because of this observation, I actually would not say that wine drinkers were at the greatest risk."