SAN DIEGO — Weight loss, type 2 diabetes, sleep apnea, liver disease, heart disease…cancer?
Drugs like Ozempic can help treat a variety of health conditions, but their effects on cancer remain unclear. During an April 18 session at the annual meeting American Association for Cancer Research At this meeting, scientists took stock of the field and assessed the evidence for any cancer prevention power.
Conclusion: the jury is still not elected.
Several studies have provided tantalizing indications of the potential benefits of these drugs, but other findings are all over the place. Scientists have linked these drugs, called GLP-1 receptor agonists, to increased survival in cancer patients And a reduction in cancers linked to obesity. However, other studies have shown little or no such association. And some research has raised, if not some red flags, maybe a few yellowish red flags. One study noted a potential increased risk of kidney cancer in people taking this medication. And work in laboratory animals has raised concerns about the development of thyroid cancer, although more recent research suggests that it is not likely in people.
Overall, the data is rather confusing, said Jennifer Ligibel, an oncologist at the Dana-Farber Cancer Institute in Boston. GLP-1 drugs have “really revolutionized weight loss,” she said. “But I think the question of their effect on cancer remains open.”
These medications include semaglutide (sold under the brand names Ozempic, Wegovy, and Rybelsus) and tirzepatide (brand names Mounjaro and Zepbound). They mimic gut hormones that play a role in digestion and metabolism, causing weight loss and acting on the body in a variety of other ways, some still unknown. As more GLP-1 drugs become available, including the recently approved Foundayo pill, and more people take them for longer periods of time, researchers may have a clearer idea of the impact of these drugs on cancer risk.
However, at this point, “you can’t really draw any strong conclusions,” said Stephen Hursting, a nutrition and cancer researcher at the University of North Carolina at Chapel Hill. Scientific news discussed open questions in the field with Hursting, Ligibel and health data scientist Jiang Bian of the Indiana University School of Medicine in Indianapolis. Conversations have been edited for length and clarity.
SN: Can we say that GLP-1 drugs prevent cancer?
GOOD : No, but I think there are some potential benefits.
Screaming: No, that wouldn’t be surprising, but we need data to be able to say for sure.
Ligibel: No not yet. I am hopeful.
SN: Why do you hope?
Ligibel: The literature on bariatric surgery clearly indicates that losing weight can reduce the risk of developing cancer. On average, you don’t get as much weight loss with GLP-1 receptor agonists as you do with bariatric surgery. But it is certain that many patients achieve very high levels of weight loss. So I think it’s very, very promising, but I wouldn’t, as an oncologist, consider the data definitive at this point.
SN: Why don’t we have a definitive answer yet?
GOOD : These medications are new and evolving. Lots of medicine [may not work the same way for every patient]. And the patient populations among the studies are different. We need more data.
Screaming: The newest and most effective drugs aren’t even really included in most of the data. Tirzepatide was only approved for weight loss two and a half years ago. [hasn’t been enough time] to see an effect on a disease like cancer.
SN: How might these drugs work to prevent cancer?
Screaming: Obesity causes a multitude of metabolic changes. There is constant low-level inflammation, immune dysfunction, high levels of hormones like insulin and leptin. We know that obesity is a major contributor to cancer, and these medications reverse many of the effects of obesity.
SN: Research suggests GLP-1 drugs may cause cancer. How concerned should patients be?
Ligibel: These models are not that consistent. There’s not a lot of preliminary data that worries me.
GOOD : I am not currently worried and have personally been taking tirzepatide for weight loss for two years.
SN: What would be needed to better understand the role these drugs play in cancer?
GOOD : Randomized clinical trials are the gold standard. But there are real limits. You can’t make a [randomized clinical trial] on all types of cancer, following patients for 20 years. So we’re going to need a combination of different types of evidence. Some will be randomized clinical trials, and others will be real-world data. [Real-world data come from patients not in clinical trials; it illustrates a medication’s use and efficacy in people’s daily lives.]
Screaming: We need more people asking questions about animal models [lab animals used to study aspects of human disease] so we get a little more clarity on which cancers are the most reactive.
SN: What are the biggest open questions in the field today?
Ligibel: Do these medications really reduce the risk of developing cancer? That’s the main thing. And could they impact cancer outcomes in people diagnosed with the disease? We have a lot more information on the first question, and there is almost nothing on the second question.
Screaming: We don’t have a good idea of the long-term effects of new drugs. I’m also interested in how we can get people to stop taking medications once they’ve lost weight. [Many people tend to regain weight once they stop using the drugs.]
SN: What do you want people considering taking GLP-1 medications to know?
Ligibel: A healthy lifestyle remains important. The quality of your diet makes the difference. People can lose muscle mass on these medications. It is therefore important that people continue to think about their health.
Screaming: These medications can be a great tool, but we need to determine the best time to use them.
They are not suitable for everyone and there will be individual differences. Some people don’t lose weight.
GOOD : There is no definitive conclusion that the drugs protect against cancer. [If you’re worried about potential harms,] you should discuss this with your doctor.