The rise of weight-loss injections has transformed obesity treatment in a way few experts predicted just a few years ago.
Medications such as Wegovy, Ozempic, Zepbound, and Mounjaro have helped many people lose substantial amounts of weight when diet and exercise alone were not enough.
Now, researchers have uncovered evidence suggesting that these medicines may do more than help people shed pounds. They may also be linked to a lower chance of developing several cancers associated with obesity.
The findings come from a large study published in Annals of Oncology. Researchers analyzed medical records from more than 229,000 obese adults in the United States who did not have diabetes.
The study focused on a question that has become increasingly important as the use of these medications continues to grow: could the health benefits of GLP-1 drugs extend beyond weight management?
Obesity affects hundreds of millions of people worldwide. Doctors have long known that carrying excess body weight increases the risk of many serious diseases. Among the most concerning are cancers linked to obesity. Scientists estimate that about 40% of cancers diagnosed in high-income countries are connected to excess body fat.
Obesity can influence cancer risk in several ways. Fat tissue produces hormones and inflammatory substances that can encourage cancer cells to grow. Excess weight can also affect insulin levels and other biological processes that may create an environment where cancer is more likely to develop.
Because of these connections, researchers have wondered whether successful weight-loss treatments could also reduce cancer risk. Until now, however, evidence has been limited, especially among people without diabetes.
The research team used data from a nationwide healthcare network that included information from millions of Americans.
They identified more than 229,000 obese adults who did not have diabetes. Some patients received prescriptions for GLP-1 receptor agonists such as semaglutide or tirzepatide, while others received counseling focused on diet and physical activity.
To make the comparison as fair as possible, researchers carefully matched people in the medication group with similar people in the lifestyle group. This approach helped reduce differences between the groups that could affect the results.
After following patients for up to two years, the researchers found that those using GLP-1 medications had a significantly lower risk of developing cancers associated with obesity. Overall, the risk was reduced by 41% compared with people who relied on lifestyle advice alone.
Some of the most impressive findings involved specific cancer types. Endometrial cancer, which affects the lining of the uterus and is strongly linked to obesity, occurred much less often among medication users. The study reported a 58% reduction in risk for this cancer.
The researchers also found that men appeared to benefit particularly strongly, with cancer risk falling by nearly 70%. Although the reasons are not yet clear, scientists believe biological differences and varying risk factors may play a role.
When researchers compared different medications, tirzepatide appeared to provide the strongest reduction in cancer risk. However, all of the GLP-1 drugs studied showed potential benefits.
One reason these findings are attracting attention is the enormous growth in GLP-1 use.
According to the researchers, the number of obese adults without diabetes using these medications in the United States increased from about 21,000 people in 2019 to more than 174,000 people in 2023. This means that understanding the long-term effects of these drugs has become a major public health priority.
Dr. Aparna Kamat and her colleagues believe the findings could represent an important step toward understanding how obesity treatment influences cancer risk. They point out that obesity-related cancers are increasingly affecting people in their forties and fifties, making prevention strategies especially important.
At the same time, the researchers urge caution. The study was not designed to prove that the medications directly prevent cancer. Instead, it found a strong association between drug use and lower cancer rates. Other factors may contribute to the results, and only randomized clinical trials can determine whether the drugs themselves are responsible.
Another important limitation is the relatively short follow-up period. Cancer often develops over many years, so future studies that track patients for longer periods will be needed.
Despite these uncertainties, the findings offer a promising glimpse into a possible new benefit of obesity treatment. If future research confirms the results, doctors may eventually view these medications as tools for reducing the risk of some cancers as well as helping patients lose weight.
The study’s strengths include its very large sample size and its focus on non-diabetic adults, a group that now represents many of today’s GLP-1 users. However, the research remains observational and cannot establish a direct cause-and-effect relationship.
The results should therefore be viewed as encouraging but preliminary. Future long-term clinical trials will be crucial for confirming whether these medications truly help prevent obesity-related cancers and for understanding which patients may benefit the most.
If you care about cancer, please read studies that a low-carb diet could increase overall cancer risk, and berry that can prevent cancer, diabetes, and obesity.
For more health information, please see recent studies about how drinking milk affects the risks of heart disease and cancer and results showing vitamin D supplements could strongly reduce cancer death.
Source: Houston Methodist Hospital.
