Why GLP-1 drugs might reduce cancer risk

A new wave of research links GLP-1 drugs to reduced cancer spread and better survival, and the mechanism may go beyond just weight loss

By Lori Youmshajekian edited by Lauren J. Young & Tanya Lewis

CHICAGO—At the world’s largest oncology conference, Ozempic, a diabetes drug, found its way to the center of the conversation. As thousands of attendees bounced between presentations at the American Society of Clinical Oncology (ASCO) meeting, some of the biggest buzz focused on the connection between taking Ozempic and similar glucagonlike peptide 1 (GLP-1) receptor agonists and having a decreased risk of several types of cancer.

GLP-1 drugs, originally designed to treat type 2 diabetes, have become blockbuster treatments for weight loss and metabolic conditions such as heart , liver and kidney disease . Now researchers are investigating whether certain cancers, such as breast cancer, could be added to that list. At the conference, scientists announced their findings that people taking GLP-1 drugs were less likely to be diagnosed with certain cancers, have them spread or die from them when compared with nonusers and those on other diabetes medications. Even though the findings are largely based on observational studies, they reinforce animal research that shows GLP-1 drugs do more than just shed pounds and improve metabolic health. The drugs may also dial down the inflammation that can drive cancer development—and might even act directly on tumors.

Obesity has long been identified as a risk factor for at least 13 types of cancer. Excess weight promotes chronic inflammation, raises insulin levels in the blood and increases estrogen circulating in the body—all potential drivers of cancer development. Whether GLP-1 treatments reduce cancer risk by reversing these pathways through weight loss, or through some other mechanism entirely, remains an open question. Several lines of research presented at ASCO offer evidence of the drugs’ protective effect against cancer, including several not typically associated with weight, such as leukemia and lung cancer, says Elizabeth McDonald, radiologist at the Hospital of the University of Pennsylvania.

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McDonald’s team at the University of Pennsylvania found GLP-1 drugs were linked to a 30 percent lower likelihood of a breast cancer diagnosis in more than 111,000 women who underwent breast imaging. Another large analysis from the Virginia Commonwealth University (VCU) Massey Comprehensive Cancer Center, published in JAMA Network Open before the conference, followed breast cancer patients for up to 10 years and found that those who took GLP-1s had a lower risk of death from any cause—and a reduced risk of cancer recurrence—compared with patients who did not take them. And in another investigation, co-led by researchers at Massey, found that GLP-1 drugs were associated with improved survival among people with colorectal cancer as well. A Cleveland Clinic study tracking people across seven cancer types found that those taking the drugs were significantly less likely to progress to stage four disease in lung, breast, colorectal and liver cancers—with a 43 percent risk reduction seen in breast cancer and a 50 percent reduction in lung cancer.

These studies collectively provide an “interesting signal,” says Jasmine Sukumar, a breast medical oncologist at the University of Texas MD Anderson Cancer Center, who also presented research on GLP-1s’ protective effect against breast cancer. The data are still observational, which means the research teams cannot prove cause and effect, she adds. Still, Sukumar and other scientists are trying to understand what might be driving these findings.