Though consumed in small amounts, alcohol seems to increase
the risk of breast cancer, particularly estrogen-receptor and
progesterone-receptor positive breast cancer in postmenopausal women, a large
Previous studies have suggested that consuming alcohol boosts the risk of breast cancer, although the precise mechanisms have not been clarified.
“For years, we've known that there's an association between alcohol drinking
and breast cancer risk, but nobody knows yet what the underlying biological
mechanisms are. The logical step was to begin analyzing the alcohol
metabolizing genes," said Dr. Catalin Marian, lead author of the study and
a research instructor in oncology at the
A U.S. National Cancer Institute team followed more than 184,000
postmenopausal women for an average of seven years.
The study showed that women who drank one to two drinks a
day had a 32 percent increased risk and those who had three or more glasses of
alcohol a day had up to a 51 percent increased risk. On the other hand, those
having less than one drink a day had a 7 percent increased risk of breast
cancer, the team reported.
However, the risk was mostly seen in women whose tumors were positive for both the estrogen and progesterone receptors. About 70 percent of women who are diagnosed with breast cancer have this kind of tumors.
"Our study shows that not only does a small amount of
alcohol significantly increase the risk of breast cancer, it increases the risk
of the most common type of breast cancer, responsible for around 70 percent of
cases," said Jasmine Lew, from the National Cancer Institute (NCI) in
America, who also led the study.
She further explained how alcohol use leads to breast cancer
by explaining: “alcohol affects estrogen metabolism, which increases risk of
hormone sensitive breast cancer. Still, more study is needed to clarify the effect of alcohol on other tumor types.”
According to the American Cancer Society, about 182,000
women in the
The findings were presented Sunday at the annual meeting of
the American Association for Cancer Research in