New Research Suggests GLP-1 Drugs May Lower Cancer Risk
Emerging evidence presented at the American Society of Clinical Oncology (ASCO) meeting in Chicago indicates that GLP-1 receptor agonists—medications originally developed for type 2 diabetes and now widely used for weight management—may be associated with a reduced risk of certain cancers, particularly those linked to obesity.
Dr. Judith Bray, vice-president of research at the Canadian Cancer Society, described the findings as potentially “transformative,” noting that while these drugs have been prescribed for diabetes for years, their possible role in cancer prevention was only recently recognized as an “accidental finding” among diabetic patients.
Obesity-Related Cancer Risk Reduced by 41%
A large-scale study published in ESMO Annals of Oncology analyzed data from over 161,000 patients (average age 47) who were obese, did not have diabetes, and had no prior diagnosis of obesity-related cancer. Half received GLP-1 injections for weight loss, while the other half were given standard diet and exercise advice. After two years of follow-up, those using GLP-1 drugs showed a 41% lower risk of developing an obesity-related cancer compared to the control group.
Breast Cancer Incidence Also Lower Among GLP-1 Users
Separate research published in JCO Oncology Practice on June 2 found that GLP-1 use was linked to a lower incidence of breast cancer, independent of age, race, ethnicity, BMI, breast density, or diabetes status. The study included more than 110,000 women aged 45–80 who underwent breast imaging between January 2022 and June 2025; nearly 14% were prescribed a GLP-1 drug.
Women taking GLP-1 medications had up to a 35% lower risk of developing breast cancer compared to non-users. In a matched-pair analysis—comparing each GLP-1 user with a woman of similar background—the risk reduction was nearly 31%.
Lead researcher Dr. Elizabeth McDonald emphasized that while the study is observational and does not prove causation, it “adds to the growing body of evidence suggesting that these weight loss drugs are worth investigating as potential cancer prevention tools.”
Canadian Experts Call for Further Research
Kimberly Carson, CEO of Breast Cancer Canada, called the findings “very encouraging” and expressed hope that future studies will confirm these results. She stressed the need for Canadian-specific data, noting that current research has not yet included Canadian populations and that Canada has the capacity to conduct such studies.
Dr. Bray echoed this sentiment, highlighting key unanswered questions: “If someone already had cancer and you gave them one of these drugs, would that actually delay or prevent the disease from metastasized or spread? We don’t have an answer to that.”
Rising Obesity Rates Amplify Urgency
The findings come amid rising obesity rates in Canada. According to Statistics Canada, 68% of adults aged 18–79 were classified as overweight or obese between 2022 and 2024—up from 60% before the pandemic. With breast cancer projected to be the most commonly diagnosed cancer in Canadian women in 2026 (accounting for 26% of cases), the potential preventive role of GLP-1 drugs could have significant public health implications.
As generic versions of semaglutide become available in Canadian pharmacies this year, access to these medications is expected to increase, potentially enabling broader research and clinical applications in oncology prevention.
