A major new study suggests that weight-loss injections could nearly halve the risk of cancers linked to obesity. Cancer specialists have hailed the research as “groundbreaking,” with the potential to usher in a “new era of preventive cancer medicine.” Obesity has been linked to 13 different types of cancer. Although losing weight is already known to lower cancer risk, scientists have found that weight-loss drugs offer additional protective benefits beyond simply reducing body weight. Researchers in Israel tracked 6,000 adults without a prior history of cancer, who either underwent bariatric surgery or used glucagon-like peptide-1 receptor agonists (GLP-1RAs) such as liraglutide (Saxenda), exenatide (Byetta), or dulaglutide (Trulicity). These medications mimic the GLP-1 hormone, helping lower blood sugar and increasing feelings of fullness.
While bariatric surgery patients lost about twice as much weight as those on medication, the study, presented at the European Congress on Obesity in Malaga, Spain, and published in The Lancet’s eClinicalMedicine, found that cancer risk reduction was similar across both groups. According to researchers, bariatric surgery reduces cancer risk by 30–42%. After adjusting for the greater weight loss from surgery, the authors concluded that weight-loss drugs were even more effective at preventing obesity-related cancers.
“The protective effects of GLP-1RAs against obesity-related cancers likely arise from multiple mechanisms, including reducing inflammation,” said co-lead author Prof Dror Dicker from Hasharon Hospital, Rabin Medical Center, Petah Tikva, Israel.
He noted that newer, more potent GLP-1 drugs may offer even stronger protection: “Next-generation GLP-1RAs with greater weight-loss efficacy could provide an even bigger benefit in lowering cancer risk, though future studies must confirm they don’t raise the risk of other cancers.”
In a related study, also presented at the conference and published in the New England Journal of Medicine, researchers compared weight-loss medications and found that patients on Mounjaro lost about 50% more weight than those on Wegovy. On average, Mounjaro users experienced a 20.2% weight reduction compared to 13.7% with Wegovy.
Commenting on the research, Professor Mark Lawler of Queen’s University Belfast, an expert in cancer research, said the observational study's results were promising but should be interpreted carefully.
“We already know bariatric surgery cuts obesity-related cancer risk by about a third; these data suggest target GLP-1s may cut that risk by nearly 50% – an approach that would be transformational in preventing obesity-related cancer.
“Biologically, this makes sense, as targeting GLP-1 dampens down inflammation, one of the hallmarks of cancer.
“While further work is required on how it works, these data raise the intriguing possibility that a GLP-1 jab could prevent multiple cancers in the general population, including common cancers like breast and colorectal, and difficult to treat cancers like pancreatic and ovarian. This work could herald a whole new era of preventive cancer medicine.”
Professor Jason Halford, former president of the European Association for the Study of Obesity and head of psychology at Leeds University, suggested that these drugs should also be tested in patients recently diagnosed with cancer to see if they improve survival.
He added the drugs had “the potential to be a new dawn. And it’s not just prevention, weight management in people recently diagnosed with cancer is also critical in terms of outcomes. That would be the next thing to look at. More and more cancers are being associated with obesity.”
At the conference, a coalition of 54 experts from 12 countries issued a statement urging that weight-loss drugs be prioritized for cancer prevention trials. In response, a UK-based research team at the University of Manchester, funded by Cancer Research UK, is preparing a large clinical trial involving tens of thousands of participants, which they aim to launch within three to five years.
Dr. Matthew Harris, of the Manchester Cancer Research Centre, said, “Weight-loss injections offer remarkable results and may finally give us a scalable intervention for population-wide use, something we’ve struggled to achieve until now.”
