Weight Loss Injections May Impact Cancer Scan Accuracy
Groundbreaking weight loss injections, used by many trying to shed pounds or manage diabetes, might make certain cancer scans, like PET-CT, less reliable, according to experts.
These medications, such as Mounjaro and Wegovy, have transformed the approach to obesity treatment, enabling individuals to lose significant amounts of weight—up to 20% of their total body weight.
However, a team of British researchers found that these injections could alter the appearance of tissues in scans, possibly leading to misinterpretations as signs of cancer.
Patients on these drugs—known scientifically as GLP-1 receptor agonists—may face unnecessary follow-up tests, as healthy tissue might appear suspicious, raising concerns about anxiety and delays in receiving appropriate treatments.
This announcement follows previous studies indicating that GLP-1 medications may also interfere with breast cancer chemotherapy treatments.
Dr. Peter Strouhal, who is the medical director at Alliance Medical and led the study, highlighted an unusual case of tracer uptake in a patient using a GLP-1 agonist, prompting an investigation across their network.
He mentioned that these altered patterns are appearing more frequently, yet there’s currently no guidance available in the UK to address these emerging challenges.
In their investigation, researchers reviewed several scans of patients utilizing these injections, revealing various atypical patterns that could be misread as dangerous. It’s important to note that areas with heightened tracer concentrations don’t always indicate cancer; they can also signify infections or inflammation.
Dr. Strouhal emphasized that recognizing patterns associated with GLP-1 drugs helps alleviate unnecessary anxiety and ensures patients receive timely and appropriate care.
Further research is necessary to solidify these findings before any revisions to scan guidelines are proposed for all users of weight loss injections. Medical professionals are encouraged to carefully consider individual patient histories when interpreting these scans.
This study will be presented on October 8 at the Annual Congress of the European Association of Nuclear Medicine in Barcelona, and ties back to earlier research that indicated GLP-1 drugs might affect breast cancer chemotherapy effectiveness.
In that earlier US study, researchers tracked hundreds of women with early-stage triple-negative breast cancer. Among these women, 25 had been taking GLP-1s alongside other diabetes medications during their cancer treatment.
Two years later, only 28% of those on GLP-1s had responded fully to their cancer therapies, in contrast to 63% of those not using the injections who were cancer-free.
Moreover, it was found that GLP-1s had begun to infiltrate tumor and immune cells from these patients. Dr. Bethania Santos, an oncologist involved in the study, noted that the application of GLP-1s needs to be weighed carefully during breast cancer treatments.
Despite these insights, experts have indicated that weight loss medications may not inherently reduce chemotherapy efficacy. Rather, the complications may stem from the fact that patients with advanced diabetes who require multiple medications generally face an increased risk of cancer recurrence. Thus, the study cannot definitively conclude if these drugs are beneficial or detrimental to cancer treatment outcomes.
