Most health experts weren’t surprised when a recent National Cancer Institute study revealed a connection between alcohol consumption and breast cancer, but it was the first study that statistically connected the dots.
The NCI sent out a survey to AARP members in 1995, asking them about their lifestyles and dietary habits. The NCI has followed the survey’s participants since then to find connections between various cancers and lifestyle choices.
One group, led by University of Chicago medical student Jasmine Lew, looked for possible connections between breast cancer and alcohol drinking habits. The result?
“We found that regular, moderate alcohol consumption was associated with an increased risk of the most common type of cancer,” Lew said.
And the more alcohol a woman drinks, Lew said, the greater her risk.
In the late 1990s, scientists found sufficient evidence that alcohol was not just a catalyst of cancer, but a carcinogen itself – which made the results of the study all the more plausible.
“We tend to find alcohol is associated with a number of certain diseases, including several types of cancers,” said University Health Center Medical Director Ben Douglas.
For example, he said, the fact that nicotine, another carcinogen, is connected to lung and oral cancers has been common knowledge for a number of decades.
But the study did not just point to the already obvious connection; it also was the first study of its kind to look at breast cancer as a group of different diseases.
“That is something pretty new,” Lew said.
The study found that the strongest connection between breast cancer and alcohol was in estrogen-receptor and progesterone-receptor-positive (ER+/PR+) cancer, the most common type. Women who drank three or more drinks daily were 51 percent more likely to develop ER+/PR+ breast cancer, whereas no link could be found between alcohol consumption and women with ER-/PR- tumors.
Scientists have yet to find the reason why the link is evident in certain types of cancer and not in others, but the NCI group’s hypothesis is that “alcohol somehow interferes with estrogen metabolism” in ER+/PR+ cases.
Another theory has to do with alcohol’s interference with the metabolism of one-carbon cells.
Either way, “the estrogen pathway is probably a main cause,” Lew said.
“The alcohol might be doing something to make the receptors in the breast tissue react differently,” Douglas theorized. “That connection is the thing that’s the puzzle right now.”
Although most college-aged women don’t worry about breast cancer this early in their lives, they should take the time to research other lifestyle choices that can increase cancer risk later in life.
Douglas said a family history of breast cancer “should be taken very seriously.” Those who have mothers, aunts or grandmothers who have had breast cancer face a much greater risk than those who don’t.
“There is also some correlation between cigarettes and breast cancer,” Douglas said.
Women who have irregular menstrual cycles or “delay having children until later in life” are also at a greater risk.
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