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Disclaimer: The following article provides information based on studies that have a relatively short follow-up period. The results of these studies may not reflect long-term outcomes, and further research is needed for a comprehensive understanding of potential risks associated with GLP-1 receptor agonist (GLP-1 RA) treatments.
Recent research sheds light on a noteworthy trend: an increase in thyroid cancer detections among patients treated with GLP-1 receptor agonists (GLP-1 RAs), though experts clarify that the higher detection rates are more likely due to intensified screening rather than an actual rise in cancer risk. The study, published in JAMA Otolaryngology-Head & Neck Surgery, suggests that while the overall risk of developing thyroid cancer associated with GLP-1 RA treatment remains low, concerns arise from early detection patterns, especially within the first year of treatment.
The Link Between GLP-1 RAs and Thyroid Cancer Detection
Dr. Rozalina G. McCoy, senior author of the study and an expert in endocrinology at the University of Maryland School of Medicine, emphasized that while patients on GLP-1 RAs are indeed more likely to be diagnosed with thyroid cancer, this is not because they are more likely to develop the cancer itself. Instead, the increased detection is attributed to more frequent screenings driven by heightened awareness of potential thyroid cancer risks associated with these medications.
“We are more likely to look for thyroid cancer in patients on GLP-1 RAs, not because they are more likely to develop it, but because clinicians are more actively searching for it,” McCoy explained in an interview with Medscape Medical News.
The initial concern over GLP-1 RAs and thyroid cancer stemmed from preclinical studies involving rodents, which suggested a potential risk for medullary thyroid cancer. However, human studies have not confirmed such a direct link. The FDA has even issued a warning about the risk of medullary thyroid cancer in patients with a family history, but concerns about other types of thyroid cancers, like papillary thyroid cancer, remain inconclusive.
Increased Screening and Early Cancer Detection
The study reviewed claims data from over 350,000 adults in the United States who were enrolled in Medicare Advantage and fee-for-service plans and were diagnosed with type 2 diabetes. It found that while the absolute risk of thyroid cancer remained low across different treatment groups (GLP-1 RAs, DPP-4 inhibitors, SGLT2 inhibitors, and sulfonylureas), the rate of detection was notably higher in the first year after initiating GLP-1 RA treatment.
Specifically, patients who began GLP-1 RA treatment had a significantly higher likelihood of receiving thyroid ultrasounds, with screening rates jumping 50% at 6 months and 40% at 12 months compared to those on other diabetes medications. These early detections are considered likely due to more proactive screening rather than an increase in actual thyroid cancer cases.
The Risk of Over-Diagnosis
McCoy and other experts are concerned that this increase in early thyroid cancer diagnoses could contribute to over-detection, a growing issue in modern medicine due to more advanced imaging techniques. Small, low-risk thyroid cancers that might not have caused harm in the patient’s lifetime could lead to unnecessary treatments, including surgeries that come with their own risks.
For patients on GLP-1 RAs, thyroid cancer screening is currently not recommended unless they have a specific risk. McCoy’s study, alongside other recent research, supports this guideline and highlights the importance of avoiding excessive testing that could lead to over-diagnosis.
Looking Ahead: The Need for Long-Term Research
The research is still in its early stages, and McCoy cautioned that the follow-up period of about two years was too short to draw conclusions about the long-term effects of GLP-1 RAs on thyroid cancer development. As more people take these medications over extended periods, further studies will be necessary to assess any potential risks of developing thyroid cancer after prolonged exposure.
Conclusion
While the study indicates a slight increase in thyroid cancer detection among those taking GLP-1 RAs, it is clear that increased screening, rather than a higher risk of cancer, is the likely cause of these findings. As the popularity of GLP-1 medications continues to rise, clinicians and patients alike should be aware of the possibility of over-diagnosis, with a focus on ensuring that only clinically significant cases of thyroid cancer are detected and treated.
For now, experts like McCoy reassure that, for most patients, there is no indication that GLP-1 receptor agonists directly cause thyroid cancer.
