A recent study has raised concerns regarding the use of GLP-1 receptor agonist medications, which are increasingly prescribed for weight loss and the management of type 2 diabetes. Researchers in the UK have found that these drugs may distort cancer scan interpretations, leading to potential misdiagnoses.
GLP-1 agonists, known for their role in altering glucose metabolism and impacting the body’s energy and stress systems, have been observed to cause ‘unique uptake’ patterns in FDG PET-CT scans. These scans are vital for identifying high metabolic activity, such as tumors or inflammation.
In prior reports, increased FDG uptake has been noted in areas such as:
- Skeletal muscle
- Heart muscle
- Brown adipose tissue — a type of fat that generates heat by burning energy
This heightened FDG uptake could potentially be mistaken for cancer or inflammatory diseases.
The latest findings were presented at the 38th Annual Congress of the European Association of Nuclear Medicine by Alliance Medical Ltd. The research team conducted a retrospective review of scans from patients treated with GLP-1 agonists. Their analysis revealed several unusual patterns of tracer uptake, which, if the patient’s medication history is not considered, could easily be misinterpreted as indicative of disease.
Dr. Peter Strouhal, the study’s lead author and medical director at Alliance, stated, “We noticed unusual uptake in one of our patients on a GLP-1 agonist, which prompted a wider review across our network. We found that these altered patterns are increasingly common, yet there is currently no national or international guidance in the UK addressing this emerging issue.”
Analysts have also noted an absence of official national guidelines in the U.S., even though emerging studies may touch on similar concerns. Meanwhile, Australian guidelines have suggested practices that include:
- Continuing treatment with GLP-1 agonists
- Fasting from midnight before scanning
- Scheduling scans for the morning
- Maintaining good glucose control
The researchers caution that misinterpretation of scan patterns could result in unnecessary investigations, improper cancer staging, and treatment delays. The implications extend beyond medical concerns, with the potential for increased patient stress when confronted with erroneous diagnoses.
Dr. Strouhal emphasized the importance of recognizing uptake characteristics associated with GLP-1 agonists, stating, “Recognizing the characteristic uptake associated with GLP-1 agonists helps avoid unnecessary anxiety and interventions, ensuring patients receive the right care, at the right time, without detours or doubt.”
At this time, the research team does not recommend altering patient preparation protocols or discontinuing the use of GLP-1 agonists prior to FDG PET-CT scans. Instead, they advocate for imaging professionals to meticulously document patients’ medication histories to improve scan interpretation as formal guidelines are developed.
Plans are underway to expand this investigation to more imaging centers in order to gather further evidence to support future guidelines. Additionally, the researchers aim to engage in international collaborations to enhance patient care globally.
