The game-changing weight loss injection that millions of slim people and diabetics rely on could make certain cancer scans less effective, experts have suggested.
These drugs, including Mounjaro and Wegovy, have ushered in a new era in the fight against obesity, helping dieters lose up to a fifth of their body weight.
But British researchers evaluating PET-CT scans to help diagnose and stage cancer found that the injections had a detrimental effect on the way tissue appeared on scans, potentially leading to them being misinterpreted as cancer.
This means that the patient The jabs, collectively known as glucagon-like peptide-1 receptor agonists, or GLP-1, were associated with a higher risk of unnecessary additional tests to probe healthy tissue.
Experts worry this could cause stress and uncertainty for patients and even lead to delays in other treatments.
It also comes just months after a study found that GLP-1 drugs could potentially interfere with breast cancer chemotherapy drugs.
Dr Peter Strouhal, Medical Director at Alliance Medical, a leading provider of diagnostic imaging services in the UK and senior author of the study, said:We discovered abnormal uptake of GLP-1 agonists in one of our patients, which prompted an extensive review across our network.
‘We are finding that these altered patterns are becoming increasingly common, but there is currently no national or international guidance in the UK addressing this new issue.’
British researchers evaluating PET-CT scans to help diagnose and stage cancer found that the injections had a detrimental effect on the way tissue appeared on scans, potentially leading to it being mistaken for cancer.
In the study, researchers reviewed several PET-CT scans of patients taking the drug after finding abnormalities in one patient.
A PET-CT scan combines a CT scan and a PET scan. It uses a mildly radioactive liquid, medically known as a radiotracer, to show areas of the body where cells are more active than normal.
Higher levels of metabolic activity and concentration of tracers on scans may indicate potential cancer activity, which appears as brighter spots.
The researchers discovered ‘atypical’ and ‘misinterpretable’ tracer patterns in the scans of GLP-1 users as hotspots, or potentially cancer-causing areas.
Hotspot areas with high tracer levels do not always indicate cancer and may be a sign of other conditions such as infection or inflammation.
‘Recognizing the characteristic uptake associated with GLP-1 agonists can help avoid unnecessary anxiety and intervention and ensure patients receive the right treatment at the right time, without diversion or suspicion,’ said Dr Strouhal.
However, further studies containing more data are essential to prove this is the case before recommendations are made to change PET-CT scan guidelines for all users of the weight loss jab, the researchers said.
Instead, clinicians should carefully consider a patient’s medical history when interpreting scan results, he added.
This study will be presented in full at the annual general meeting of the European Association of Nuclear Medicine to be held in Barcelona on October 8.
This comes after a study late last year found that GLP-1 drugs could potentially interfere with breast cancer chemotherapy drugs.
The US study followed hundreds of women with early-stage triple-negative breast cancer throughout and after treatment.
Dozens (25) were already taking GLP-1 along with other diabetes medications and continued to take it while undergoing cancer treatment.
Tests two years later showed that only 28% of the women who received GLP-1 responded completely to their cancer treatment and were cancer-free.
Among people who did not use GLP-1, more than twice as many (63%) did not develop cancer.
Researchers also discovered: GLP-1 penetrated tumor cells and Immune cells from samples taken from patients.
“The use of GLP-1 during breast cancer treatment may need to be carefully considered,” said Dr. Bethania Santos, an oncologist and researcher at UT Southwestern Medical Center in Dallas, who presented the study at the San Antonio Breast Cancer Symposium.
But experts at the time suggested that the weight-loss drugs themselves may not have reduced the effectiveness of chemotherapy.
Rather, patients with advanced diabetes who require multiple drug treatments have a higher risk of breast cancer recurrence.
They said the study did not demonstrate whether weight loss drugs help or impair the effectiveness of cancer treatment.
