There is mounting evidence to suggest GLP-1 obesity treatments also help reduce cancer risk, according to several recent studies. The studies are correlative, but appear to show the drugs not only reverse the carcinogenic risks that come with obesity, they may also have additional anti-inflammatory effects that help suppress tumors.
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GLP-1 drugs' potential use in preventing or controlling cancer was a major theme among the research presented at the influential American Society of Clinical Oncology meeting last month.
The group highlighted four studies — some of which were published in its affiliated Journal of Clinical Oncology. The most prominent among them tracked medical and prescription records of over 10,000 patients with early-stage cancer, and found GLP-1s reduced cancer risk in 6 out of 7 cancers – four of them at statistically significant levels. Breast, liver, colorectal and non-small cell lung cancer risks declined significantly; kidney and prostate declined somewhat; pancreatic cancer rates were affected the least.
It's notable that the effects were seen across cancers, not just those with a known connection to obesity. For non-small cell lung cancer, for example, the incidence of progression to Stage IV disease was 22.3% for patients not on a GLP-1 versus 10% among people taking GLP-1s.
GLP-1 drugs were originally developed decades ago as diabetes treatments that alter the hormonal makeup of the brain and gut — reducing hunger and slowing digestion. Because the drugs act on powerful metabolic levers, they've also since proven useful against obesity, heart disease, sleep apnea, as well as potentially addiction and now cancer.
Studies show just correlation, so far
Experts say these latest data are still far from being able to conclude that GLP-1s are effective treatments for cancer. These analyses used retrospective medical databases that did not include relevant nuances like a patient's comorbidities, or their exercise or eating habits, for example, says Dr. Julie Gralow, chief medical officer of ASCO.
But, Gralow says, the data is consistent with what is known about how obesity is a driver for about a dozen cancers, and how healthy living is significant in both illness and recovery.
"It ties into a body of knowledge about exercise and healthy lifestyles after a cancer diagnosis."
Breast cancer risk reduction
Another data analysis, also presented at the research conference, matched mammogram images to a prescription database showing women between age 45 and 80 who took GLP-1 drugs were 30% less likely to develop breast cancer. Cancer risks decline in general when patients lose weight, whether that is through diet or bariatric surgery, for example. But radiologist Elizabeth McDonald at University of Pennsylvania who co-authored that study says the protective effects with GLP-1s appear greater than with other treatments or lifestyle changes. "The weight loss alone just didn't account for the magnitude of the observed effect," McDonald says.
How?
McDonald suspects that GLP1 medicines, as they regulate hunger and digestion hormones, also trigger other metabolic pathways. They may reduce inflammation, for example, which is a known driver of cancer.
New research underway
More trials are now starting to look at how GLP-1s might influence things like chronic inflammation, or immunosuppression, both of which might contribute to cancer growth.
Oncologist Coral Omene at Rutgers Cancer Institute, for example, plans to follow 40 breast-cancer patients starting tirezepatide, a GLP-1 drug sold under the brand names Mounjaro and Zepbound. Omene plans to regularly measure blood samples and track changes in cancer markers, and biopsy participants' abdominal fat cells every six months, to see how those respond, in terms of hormones or inflammation. "And as we're treating them, we are going to trace and see how the immune cells are behaving," Omene says.
That information, she says, will hopefully lead to better understanding as to how best to use GLP-1 drugs against cancer.
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