A new study suggests that women who drink several alcoholic drinks a day can increase their risk of developing a common type of breast cancer by as much as 50 per cent.

The study found that the more alcohol a woman drinks, the greater her likelihood of developing tumours that are positive for estrogen and progesterone receptors.

"This suggests that a woman should evaluate consumption of alcohol along with other known breast cancer risk factors, such as the use of hormone replacement therapy," said Jasmine Lew, who led the research for the U.S. National Cancer Institute, in a release.

The research did not suggest any link between alcohol and other types of breast cancer.

According to the research, alcohol increases the amount of estrogen metabolites, which can drive the growth of hormone-sensitive breast cancer.

The study reviewed findings from a study of 184,418 postmenopausal women in the United States, who were interviewed about their daily alcohol consumption.

Of the study participants, 70 per cent consumed alcohol. The average consumption among the drinkers was just under one drink per day.

The study found 5,461 cases of invasive breast cancer. Other forms of hormone-sensitive breast cancer were also tested but the strongest link was found with estrogen- and progesterone-positive breast cancer tumours.

The study found that the respondents who consumed:

• Less than one drink a day had a seven per cent increase in relative risk.
• One to two drinks a day had a 32 per cent increase.
• Three or more drinks a day had a 51 per cent increase.

"Our study at this point provides evidence for the notion that alcohol affects estrogen metabolism, which increases risk of hormone sensitive breast cancer," Lew said.

The findings are being presented at the American Association for Cancer Research 2008 annual general meeting being held April 12-16 in San Diego.