Weight-loss drugs can cut the risk of developing or dying from cancer by 30%, doctors have said.
Millions of people already use the drugs to treat obesity. Now a series of studies presented at the world’s largest oncology conference suggest the drugs could play a role in preventing and treating cancer.
One analysis found those who took GLP-1 medications were 30% less likely to develop breast cancer, the world’s most common form of the disease, compared with those not taking weight-loss drugs.
A second study found adding weight-loss drugs to standard treatment for breast cancer reduced the risk of patients dying from the disease by 30%.
A third piece of research, in patients with breast, lung, bowel or liver cancer, found those on weight-loss drugs were up to 50% less likely to have their disease spread.
The findings were shared at the American Society of Clinical Oncology’s annual meeting in Chicago.
GLP‑1 medications are a class of drugs that mimic a natural hormone in the body called glucagon‑like peptide‑1, which helps regulate blood sugar and appetite. Originally used to treat type 2 diabetes, they are now also widely used for weight management.
The first study, a retrospective analysis of 110,000 women aged between 45 and 80, found those who took GLP-1 medications were 30% less likely to develop breast cancer than those who did not.
The findings were presented by Dr Elizabeth McDonald, a professor of radiology at the University of Pennsylvania and a breast radiologist at the Abramson Cancer Center.
She said: “While our study was observational and does not definitively confirm an association between GLP-1 medications and reduced breast cancer incidence, it does add to the growing body of evidence suggesting that it’s worth investigating these weight-loss drugs as potential cancer prevention tools.
“GLP-1 medications are intriguing from a cancer research perspective because they weren’t designed for cancer therapy, but they do affect many different targets and pathways associated with cancer development, so we’re eager to study them in this context.”
GLP-1 medications are highly effective at helping people lose weight, and maintaining a healthy weight has long been recommended as a way to ward off breast cancer. Being overweight or obese, particularly after menopause, is a known risk factor for breast cancer.
Researchers have also long suspected that low-grade inflammation may play a role in breast cancer development. GLP-1s reduce systemic inflammation via different pathways and have other metabolic and epigenetic effects that could inhibit tumour growth.
McDonald believes multiple effects of weight-loss drugs inhibit breast cancer development. “Ultimately, we want to find better options to prevent breast cancer. It’s been encouraging to see the survival rates for breast cancer improve over recent decades, and we’d love to see the same gains in prevention,” she said.
The second study, involving 27,000 breast cancer patients, was led by IRCCS Istituto Romagnolo per lo Studio dei Tumori Dino Amadori, a cancer centre in Meldola, Italy. Adding weight-loss drugs to standard treatment was associated with a 30% reduced risk of death, researchers found.
The third study, involving 12,000 cancer patients and led by the Cleveland Clinic, found that in lung, breast, bowel and liver cancer, people who took weight-loss drugs were 38% to 50% less likely to develop stage-four forms of the disease than people who did not.
Dr Marcin Chwistek, the director of the supportive oncology and palliative care programme at Fox Chase Cancer Center in Philadelphia, who was not involved with the research, said: “GLP-1 receptor agonists have never been just glucose-lowering drugs. Their anti-inflammatory and immune-modulatory properties have long suggested broader effects.”
Dr Eleonora Teplinsky, the head of breast and gynaecologic medical oncology at Valley Health System in New Jersey, who also was not involved with the research, said the evidence was not clear yet as to whether the potential benefits of weight-loss drugs in the fight against cancer were just as a result of weight loss or due to other factors.
“I think there is enough data to show there is clearly some impact on either cancer risk or the risk of recurrence, but we haven’t yet defined it exactly,” she said. “We need to do more studies putting patients on them and seeing what happens.
“There are also signals that they may help with side-effects. My patients who are on GLP-1s often feel better and it helps with a lot of the side-effects from their hormone blockers. Interest in this area is climbing exponentially. It’s a very hot topic right now and hopefully we can capitalise on that.”
