Weight-loss drugs' impact on cancer risk revealed in new study

Fox News

14-05-2025

Weight-loss medications and bariatric surgery have both been found effective at helping people shed excess pounds — and now a new study explores their link to obesity-related cancer (ORC) risk.
Obesity is a known risk factor for certain types of cancers, and has also been shown to impact cancer survival.
Obesity-related cancers include multiple myeloma, meningioma, adenocarcinoma of esophagus; stomach, colorectal, liver or bile duct, gallbladder, pancreas, uterus, ovary, renal-cell kidney, thyroid, and postmenopausal breast cancer, according to the Centers for Disease Control and Prevention (CDC).
Researchers at Clalit Health Services in Tel Aviv, Israel, conducted an observational study of the medical records of 6,356 participants aged 24 and older who had obesity and diabetes, with no history of obesity-related cancer.
Between 2010 and 2018, half of the participants took GLP-1 receptor agonists (GLP-1 RAs) — injectable medications for obesity and type 2 diabetes — with at least six drug purchases within 12 months. The other half underwent bariatric metabolic surgery (BMS).
After adjusting for other factors, the researchers determined that ORC occurred in 5.62 cases per 1,000 person-years in those who had the surgery, and in 5.89 cases per 1,000 person-years among those who took GLP-1s.
Overall, the study determined that "the direct effect of GLP1-RAs compared to BMS on the risk for ORC beyond their effects on weight-loss is estimated as 41% relative risk reduction."
The findings were published in the journal eClinicalMedicine.
"The results point at the existence of additional pathways beyond weight loss in which GLP-1RAs contribute to the decreased risk for obesity-related cancer," lead study author Yael Wolff Sagy, PhD, head of research at Clalit Health Services, told Fox News Digital.
Niketa Patel, professor of molecular medicine with the USF Health Morsani College of Medicine in Tampa, Florida, noted that obesity is associated with chronic inflammation.
"GLP1-RAs are shown to reduce inflammation and thus decrease the risk of developing ORC," she told Fox News Digital. (Patel was not involved in the study.)
"The anti-inflammatory properties of these medications address a known risk factor for various cancers."
"Bottom line: Obesity can cause certain cancers, and treatment of obesity with GLP1-RA reduces the risk of only obesity-related cancers."
Dr. Britta Reierson, MD, medical director of knownwell, a provider of metabolic health services, said there are several ways in which GLP-1 RAs could have cancer mitigation properties.
"First, the anti-inflammatory properties of these medications address a known risk factor for various cancers," the Minnesota-based doctor, who also was not part of the research, told Fox News Digital.
"Second, the metabolic regulation and improvement in metabolic health from these medications, including lowering blood glucose levels and decreasing insulin resistance, can reduce cancer risk."
Emerging evidence also suggests that GLP-1 RAs may have direct anti-tumor effects, Reierson noted — "potentially through modulation of immune responses and epigenetic changes (changes that occur to gene expression and are passed down to future generations)."
Research suggests that GLP-1 medications help reduce inflammation not just through weight loss, but also in other organs of the body, such as the heart, according to Dr. Susan Savery, MD, a board-certified obesity medicine and primary care physician with PlushCare, a virtual health platform offering primary care, therapy and weight management services.
"Over time, chronic inflammation can be a risk factor for cancer development, as it may damage cell DNA," San Francisco-based Savery, who was not involved in the study, told Fox News Digital.
"Our fat cells (adipose tissue) naturally produce inflammatory cells, and GLP-1 medications, similar to bariatric surgery, help reduce this inflammation by decreasing the amount of adipose tissue through weight loss."
The study did have some limitations, the researchers acknowledged.
"First, it is an observational study. It means that our comparison groups (persons who had surgery versus those who received GLP1-RAs) may still have some residual differences, despite our methodological efforts," Sagy told Fox News Digital.
"However, only this type of real-life observational study can provide the long follow-up period that is necessary to evaluate the risk of developing cancer, which often has very long latency periods."
Another limitation is that the primary drug included in the study was liraglutide (Saxenda, Victoza), with smaller numbers of people taking exenatide (Byetta) and dulaglutide (Trulicity).
"It will be important to evaluate the comparative effectiveness of the newer GLP1-RA drugs, which are expected to have a larger effect," Sagy said.
"Although the direction of the results is promising, we should wait and see if and how clinical guidelines will consider it."
Reierson agreed that much more research is needed before GLP-1 RAs could ever be considered as cancer prevention options.
"Larger, randomized, controlled trials are necessary to confirm the observed effects and better understand the underlying mechanisms," she said.
"It will also be important to investigate the impact of GLP-1 RAs on different types of cancer and assess the long-term safety and potential side effects of using GLP-1 RAs as a cancer therapy."
Savery agrees that it's likely too early to predict FDA approval for cancer therapy, but noted that "weight reduction plays an important role in cancer prevention, and GLP-1s seem to offer an additional benefit through inflammation reduction."
While GLP-1 RAs are "wonderful tools" that can support people on weight-loss journeys, Savery pointed out that maintaining a healthy lifestyle through nutritious eating and regular physical activity is "the foundation for cancer prevention and better overall health."