At a glance
- Diabetic patients taking drugs called GLP-1 receptor agonists had a lower risk of colorectal cancer than patients prescribed other diabetes drugs.
- Further research is needed to understand how GLP-1 receptor agonists reduce colorectal cancer risk.
People who are obese are at increased risk for many chronic health problems. These include type 2 diabetes and heart disease. Obesity also increases the risk of many common cancers, including colorectal cancer.
Doctors often prescribe medications for people with type 2 diabetes. These include metformin, insulin, and other drugs that help manage blood sugar (blood sugar) levels to reduce long-term complications of diabetes.
Over the past two decades, a class of antidiabetic drugs called GLP-1 receptor agonists (GLP-1RAs) have become available to patients with type 2 diabetes. These drugs (Ozempic, Trulicity, Wigoby, Zepbound, etc.) not only help control blood sugar, but they also promote weight loss. They reduce appetite by affecting the brain and by slowing the movement of food through the digestive tract.
Researchers believe these drugs may reduce the risk of other diseases in people with type 2 diabetes. In a new study partially funded by the NIH, a research team led by Drs. Rong Xu and Nathan Berger of Case Western Reserve University and the Case Comprehensive Cancer Center conducted research on colorectal cancer. I have considered the question.
Researchers examined the medical records of more than 1.2 million people with type 2 diabetes who were prescribed antidiabetic drugs between 2005 and 2019. The research team identified newly diagnosed cases of colorectal cancer during up to 15 years of follow-up. They then compared the risk of developing colorectal cancer among people taking seven different antidiabetic drugs.
To compare the drugs, the team matched people between groups based on known risk factors for colorectal cancer, other pre-existing conditions, age, gender, race, and socioeconomic status. Thousands of such matches were made between each drug. The results will be announced on December 7, 2023. JAMA Oncology.
The research team found that, overall, patients with type 2 diabetes who took GLP-1RA had a lower risk of developing colorectal cancer than those who took other drugs. People taking GLP-1RA had a 44% lower risk of developing colorectal cancer than people taking insulin. They had a 25% lower risk than people who took metformin.
This reduced risk was seen regardless of whether people were obese or overweight. Among people with excess weight, GLP-1RA users had an even greater reduction in colorectal cancer risk. This group had a 50% lower risk of developing colorectal cancer than the group taking insulin and a 42% lower risk than the group taking metformin.
A small but significant reduction in colorectal cancer risk was also seen with the use of GLP-1RAs in obese or overweight people compared with other antidiabetic agents.
“[This] “The research is critical to reducing the incidence of colorectal cancer in people with diabetes, regardless of whether they are overweight or obese,” says Berger.
These findings suggest that GLP-1RA may protect against colorectal cancer in patients with type 2 diabetes, regardless of body weight. Further studies are needed to confirm these observations, determine whether GLP-1RA can reduce the risk of other obesity-related cancer types, and understand its mechanism of action.
—Written by Sharon Reynolds
Funding: NIH’s National Cancer Institute (NCI), Office of the Director (OD), National Institute on Aging (NIA), and National Institute on Alcohol Abuse and Alcoholism (NIAAA). American Cancer Society. Landon Foundation.
