Adolescent girls and young women with a family history of breast cancer would be well advised to avoid alcohol – or at least limit the amount they drink.
A new study suggests that booze can give an additional boost to their already elevated chances of developing the disease.
"The more you drink, the higher your risk," said the senior author of the study, Graham Colditz of Washington University School of Medicine in St. Louis.
The study, one of the first to look at early alcohol consumption and breast disease, began in 1996 with more than 9,000 girls between the ages of nine and 15. In subsequent years, they completed a series of questionnaires that tracked their family medical history, alcohol consumption, height, weight, age of first menstrual cycle and other factors associated with increased odds of developing breast cancer.
In 2005 and 2007, when the participants were between the ages of 18 and 27, they were asked if they had been diagnosed with benign breast disease that includes lumps, pain and lesions, which are known risk factors for breast cancer.
As expected, young women whose mothers or aunts had breast cancer were more than twice as likely to be diagnosed with benign breast disease compared to those with no family history.
When the researchers then took drinking habits into account, alcohol consumption further increased the risk. The more alcohol the girls consumed, the more likely they were to develop benign breast disease, according to the results published this week in the journal Cancer.
"Among young women with a family history, we can see those who didn't drink had a substantially lower risk of benign lesions than those who did drink," said Dr. Colditz.
"To me, these results sharpen the focus on the need to address prevention in the adolescent years."
Previous studies, he noted, have shown that breast cells are especially vulnerable to carcinogens when they are dividing and growing during the teen years and early adulthood – a time when many are binge drinking.
And the fact that some of the young women in the study have already been diagnosed with benign breast disease is not a good sign.
"These benign lesions are the first signs of abnormal growth. It's a real marker that these cells are behaving badly," said Dr. Colditz, adding that some of these cases will eventually become cancerous.
Of course, the researchers can't yet say which of these young women will be diagnosed with cancer in future decades. And other health experts point out that only a small fraction of benign growths eventually become malignant.
Still, in the absence of other cancer-prevention strategies for women with a family history of the disease, abstaining from alcohol "may pay off down the road," said Dr. Colditz.