New data are driving recommendations from groups around the world suggesting that any degree of alcohol intake may increase the risk of breast cancer.

“The link between alcohol use and breast cancer has been known about for a long time,” said Seema A. Khan, MD, Bluhm Family Professor of Cancer Research and Professor of Surgery at Northwestern University Feinberg School of Medicine. “There is a pretty good consensus now that less alcohol consumption is better.”

During the 2025 San Antonio Breast Cancer Symposium®, Dr. Khan will moderate Special Session 1: Open Bar and All You Can Eat? The Impact of Lifestyle in Breast Cancer Risk and Recurrence on Tuesday, December 9, from 11 a.m. to 12:30 p.m. CT in Stars at Night Ballroom 1-2 at the Henry B. Gonzalez Convention Center. The session will focus on how alcohol consumption and obesity impact breast cancer risk, as well as ways in which lifestyle changes may reduce risk.

Teasing out those links is no small task, Dr. Khan said.

Epidemiological data suggest that alcohol use alters the hormonal environment, which may play a role in breast cancer risk, she said. Alcohol also alters the permeability of the cell membrane, which may alter permeability and the trafficking of lipids, proteins, and other molecules between cells and tissues.

Julie R. Palmer, ScD, MPH, Karin Grunebaum Cancer Research Professor and Director of the Slone Epidemiology Center at Boston University Chobanian & Avedisian School of Medicine, will discuss the latest findings in the genetics of alcohol metabolism and breast cancer risk.

Differences across populations in the ability to metabolize alcohol, including the rate at which it is metabolized, complicate efforts to identify alcohol-specific effects on breast and other cancers, Dr. Khan noted. Other complications include social and cultural tendencies that tend to combine unhealthy behaviors such as excessive alcohol intake, decreased physical activity, and increased caloric intake.

Mary Beth Terry, PhD, Professor of Epidemiology and Environmental Sciences at Columbia University Mailman School of Public Health, will explore the latest findings on the effects of alcohol consumption and cessation on breast cancer risk. New data are challenging conventional views that low-order alcohol use had limited impact on breast cancer risk. The current view is that any degree of alcohol exposure increases breast cancer risk and that risk increases with increased alcohol consumption.

“There was this idea for a while that cardiovascular risk is decreased by low levels of regular alcohol consumption. That is not favored as much anymore,” Dr. Khan said. “The usual recommendation now is if you don’t drink, don’t start. And if you do drink, either stop or seriously reduce your consumption. That message has gotten stronger with additional guidance from several organizations.”

Kristy A. Brown, PhD, Associate Professor of Cell Biology and Physiology at the University of Kansas Cancer Center, will wrap up the presentations by speaking about the current understanding of molecular links between obesity and breast cancer.

Stacey Tinianov, MPH, BCPA, of Advocates for Collaborative Education, will share the patient advocate perspective during a panel discussion period following the presentations.