Alcohol's Impact on Breast Cancer Risk

Limiting or avoiding alcohol can lower your risk of breast cancer
By Trevor Bayliss, M.D.

Among the many lifetime risks for developing breast cancer, consumption of alcohol is one that continues to emerge as a contributing factor, and one that – unlike other risks that are beyond a person’s control – can readily be lowered by limiting or eliminating alcohol altogether.

Studies have shown that breast cancer is caused not by a single factor, but by a combination of multiple factors over a person’s lifetime. Some of those risk factors are things a person simply cannot change, such as being a woman versus a man, getting older, having a genetic mutation or a family history of breast cancer.  But there are many common risk factors than can be changed or mitigated by making better lifestyle choices, such as maintaining a healthy weight and diet, staying physically active, not smoking and reducing or eliminating your intake of alcohol.

Alcohol use accounts for about six percent of all cancers and four percent of all cancer deaths in the U.S., according to the American Cancer Society. The significant rise in alcohol use during the COVID-19 pandemic has public health experts concerned about a related rise in cancer risk.

For breast cancer specifically, one major study found that compared to women who don't drink at all, women who have three alcoholic drinks per week have a 15 percent higher relative risk of breast cancer. The study estimated the risk of breast cancer goes up another 10 percent for each additional drink women regularly have each day.

Researchers on this topic are particularly concerned about the window of time in a woman’s life between her first menstrual period and her first pregnancy, a time when developing breast tissue is particularly susceptible to carcinogens. Breast cancer risks accumulate across a woman's life, but the most rapid accumulation occurs during this phase. This also happens to be a time frame in which many girls and young women are experimenting with or regularly consuming considerable amounts of alcohol.

Although the precise cause-and-effect link between alcohol consumption and breast cancer is still being examined, research to date consistently has shown that drinking alcoholic beverages in various forms – beer, wine and liquor – specifically increases a woman's risk of hormone-receptor-positive breast cancer, a type of cancer that is fueled by the hormone estrogen. Two-thirds of all breast cancers in women are hormone receptor-positive. By changing the way a woman’s body metabolizes or processes estrogen, alcohol intake can elevate levels of estrogen and other hormones associated with this type of cancer.

Studies have suggested the risk increases the younger a girl begins drinking alcohol. Teen and pre-teen girls aged 9 to 15 who drink three to five drinks a week have three times the risk of developing benign breast lumps, which are associated with a higher risk of breast cancer later in life.

Given the high prevalence of youth alcohol consumption, it is important that parents and health care providers educate girls and young women about the lifelong risk of breast cancer from alcohol use.

While only a few studies have been done on drinking alcohol and the risk of recurrence in women previously diagnosed with cancer, a 2009 study found that drinking even a few alcoholic beverages per week (three to four drinks) increased the risk of breast cancer coming back in women who had been diagnosed with early-stage disease.

For anyone determined to do everything possible to lower their risk of breast cancer, limiting your consumption of alcohol is one obvious step you can take.  Some may choose to skip alcohol completely. Others may choose to moderate their consumption to a few drinks per week. The choice – and the risk – is yours.

Trevor Bayliss, M.D., a hematologist-oncologist, is Director of the BMC Cancer Center in Pittsfield.