Ozempic and other GLP-1 receptor agonists have garnered significant attention for their weight-loss benefits. However, concerns persist regarding potential long-term side effects, including a possible link to thyroid cancer. This concern is serious enough that the FDA requires GLP-1 drugs to carry warnings advising individuals with a family history of certain cancers to avoid their use. This article delves into the research exploring this connection and clarifies the current understanding of the relationship between GLP-1 drugs and thyroid cancer.
While the first GLP-1 medication for type 2 diabetes entered the market 20 years ago, numerous studies have investigated the potential link to thyroid cancer. A recent study published in JAMA Otolaryngology–Head & Neck Surgery, along with much of the existing research, found no significant increase in thyroid cancer risk associated with GLP-1 use compared to other diabetes medications. We spoke with study author Dr. Rozalina McCoy, an endocrinologist at the University of Maryland, to understand the nuances of these findings.
The Origin of the Concern
The initial concern stemmed from preclinical studies in rodents, where C-cell tumors, a rare type of thyroid cancer, were observed. This led to FDA warnings against GLP-1 use in individuals with a personal or family history of medullary thyroid cancer. Subsequent research in humans aimed to determine if this risk translated to the human population. However, clinical trials, often limited in duration and participant numbers, have not definitively answered this question.
Addressing Limitations of Previous Research
Dr. McCoy’s research aimed to address limitations of earlier studies by using a larger and more diverse dataset encompassing various insurance types and health systems. This allowed for the inclusion of nearly 400,000 patients, with approximately 41,000 treated with GLP-1s. The study also meticulously analyzed thyroid cancer diagnoses from the commencement of treatment, focusing on the first year, second year, and beyond. This approach aimed to clarify discrepancies observed in prior research, where studies neglecting the initial months of treatment often reported no increased risk.
Key Findings and Interpretations
The study revealed no overall increase in thyroid cancer risk associated with GLP-1 use over the entire study period. However, a slight increase was observed within the first year. Further investigation revealed a significantly higher rate of thyroid ultrasounds among GLP-1 users. This is crucial because of the known issue of overdiagnosis in thyroid cancer, where benign lesions are sometimes classified as cancer. The increased rate of ultrasounds likely explains the initial increase in diagnoses observed in the first year, attributing it to increased detection rather than an actual increase in cancer development.
Why More Ultrasounds?
Several factors may contribute to the increased ultrasound rates among GLP-1 users. Patients, aware of the FDA warnings, might be more inclined to seek examination if they notice any neck abnormalities. Clinicians, too, might recommend prophylactic ultrasounds, particularly for patients with a family history of thyroid problems (though usually unrelated to cancer). Additionally, weight loss induced by GLP-1s can make pre-existing nodules more palpable, leading to further investigation.
Balancing Risks and Benefits
Dr. McCoy emphasized that the decision to start any medication should involve a careful evaluation of individual benefits and risks. GLP-1s offer demonstrable benefits for patients with heart disease, heart failure, chronic kidney disease, and obesity-related complications. These benefits often outweigh the potential risks, which primarily include gastrointestinal side effects like nausea, diarrhea, and bloating. Rapid weight loss can also increase the risk of gallstones.
Conclusion
The research suggests that GLP-1s do not increase the incidence of thyroid cancer but may lead to more frequent diagnoses due to increased surveillance. The decision to use GLP-1s should be personalized, considering individual risk factors and potential benefits. Open communication between patients and clinicians is essential to ensure informed decision-making. For many, the benefits of GLP-1s in managing serious health conditions outweigh the potential risks.
