Another perk of weight-loss drugs? Fewer colon cancer deaths, a study found

• Colon cancer patients taking GLP-1 drugs, like Ozempic, had better odds of survival in a new study.
• Weight loss and diabetes injections have well-known anti-inflammatory benefits.
• It could be that Ozempic starves tumors, turning off key pro-cancer proteins.

First, they were diabetes drugs. Then, weight loss blockbusters.

Now, scientists believe they have identified another potential benefit of injectable GLP-1 drugs like Ozempic and Mounjaro: fewer colon cancer deaths.

In a recent study, researchers at the University of California discovered that colon cancer patients who happened to be taking a GLP-1 drug like Ozempic or Mounjaro cut their risk of death in half over a five-year period.

Professor Raphael Cuomo, lead author of the new research, said his team tried to find other explanations for the trend. Perhaps the people who weren't taking GLP-1s had other health issues, like depression or kidney disease, impacting their chance of survival. Nothing stuck.

Even when controlling for all of those issues and more, there was "still a consistent, significant association between GLP-1 drug use in colon cancer patients and improved survival," Cuomo said.

Cancer patients on GLP-1s were also less likely to have advanced colon cancer symptoms, such as sepsis, and suffered fewer strokes and heart attacks during the study period.

That made Cuomo, a cancer epidemiologist at the University of California, San Diego, think there must be some wider benefit to the drug, one that goes beyond just fighting back cancer directly.

Why weight loss injections might be able to starve cancer

This effect probably boils down to how GLP-1 drugs improve systemic inflammation, Cuomo said.

GLP-1 drugs lower inflammation across the body in several different ways, which is a big part of why researchers are studying whether they might improve longevity, or prevent cognitive decline, as well as improve conditions like fatty liver disease, and prevent more heart attacks.

Tumors love inflammation. They thrive in an inflammatory environment, feeding off the growth factors that inflammatory cells release to live, grow, and thrive. GLP-1s reduce inflammation in several different ways. Indirectly, they help fight inflammation through regulating blood sugar and promoting weight loss. But they also go after inflammation head-on, changing the way a person's immune system operates, and suppressing pro-inflammatory proteins. That's all bad news for a tumor.

"Potentially by taking the GLP-1 drugs, the patient is short-circuiting the tumor microenvironment," Cuomo said.

Looking at records of 6,871 patients across the University of California statewide health system, researchers found that patients on the weight loss and diabetes injections had a roughly 15.5% five-year mortality rate, compared to 37.1% mortality for colon cancer patients who took no GLP-1 drug.

Not everyone seemed to benefit equally from taking Ozempic or Mounjaro. For cancer patients with a "normal" BMI — under 25 — taking a GLP-1 drug didn't seem to impact survival at all.

On the other hand, people with a BMI over 35 who were on a GLP-1 during treatment more than doubled their survival odds, from 15% to 37%, on average.

Why? Cuomo suspects it may have to do with the unique ways that cancer behaves in different bodies. Perhaps in patients who are shouldering a lot of systemic inflammation, the GLP-1 has a more potent anti-inflammatory impact on tumor development. For patients with less inflammation, there might not be much need for a GLP-1 drug.

It's still too early for doctors to start prescribing GLP-1s to all overweight cancer patients, though. The next logical step would be for doctors to test GLP-1s head-to-head against a sham placebo drug, to prove GLP-1s really do help colon cancer patients live longer.

"I'm the first to caution people that these results are not conclusive and that we need to replicate them in randomized trials in order to be more confident that there is a benefit for cancer patients," Cuomo said. "That being said, everyone I've spoken to is very hopeful that this can be beneficial for cancer patients."

Colon cancer is quickly becoming one of the deadliest cancers in young people. It's already the number one cause of cancer death in men under 50, and in women in the same age group, it's second only to breast cancer, with death rates rising every year.