The risk of tumors that were both estrogen receptor-positive and progesterone receptor-positive increased by 8 percent per drink per day. The risk of estrogen receptor-positive but progesterone receptor-negative cancers increased by 12 percent per drink per day.
Both lobular cancers and hormone receptor-positive cancers have better survival rates than the others.
"Minimizing alcohol intake will decrease breast cancer risk, and there are a lot of things we know that increase risk similar to what alcohol does. No one factor in particular is going to cause breast cancer in itself. They're probably all related and we're trying to figure out what the multiple factors are that cause breast cancer for women," Kimmick said.
"We know that alcohol is a well established risk factor associated with breast cancer. What was unique about this study is that they tried to differentiate the type of cancer," said Dr. Sandhya Pruthi, a breast health specialist with the Mayo Clinic in Rochester, Minn. "There are so many different varieties of cancer, invasive ductal being the most common, representing about 70 percent of all breast cancer diagnoses."
While the findings don't have much clinical relevance -- since women don't know beforehand if or what type of breast cancer they might develop -- Pruthi suggested that this might spur research into whether other risk factors, for example, having your first period very young, might be associated with specific types of cancer.
"This shows that alcohol is a risk [factor] for developing breast cancer, and I think that women should be counseled that [drinking alcohol] does increase risk of breast cancer," added Dr. Jay Brooks, chairman of hematology/oncology at Ochsner Health System in Baton Rouge, La. "Women should be advised [of the risk] but she has to make a decision how important having alcohol in her life is."
All rights reserved