PET/CT scans reveal biological activity of aggressive head and neck tumors

A research team led by the Medical University of Vienna has demonstrated in a recent study that the biological characteristics of a subgroup of head and neck tumors - which are very aggressive in many cases - are reflected in modern imaging techniques. PET/CT scans can thus provide clues to particularly active and prognostically unfavourable tumor types, thereby opening up new prospects for personalized treatment strategies for a type of cancer that has hitherto been difficult to treat. The results were published in the journal Molecular Cancer.

Head and neck squamous cell carcinomas are among the most common tumors affecting the oral cavity, pharynx and larynx. The study focused on a group of head and neck tumors caused not by the human papillomavirus (HPV) but by excessive alcohol and tobacco consumption. These are considered particularly difficult to treat and often have a poor prognosis. At the same time, there still is a lack of reliable markers that would enable a more accurate assessment of the disease course and targeted treatment planning. The study by the research team led by Stefan Stoiber (Centre for Pathophysiology, Infectiology and Immunology, MedUni Vienna) and Lukas Kenner (Department of Pathology, MedUni Vienna) shows that modern imaging techniques can help to detect particularly aggressive forms of head and neck cancer at an early stage. Specific patterns in positron emission tomography/computed tomography (PET/CT) scans, which are routinely performed in cancer diagnostics, reflect the biological activity of the tumor and could enable more targeted treatment in the future.

Specific signaling pathway particularly active in tumors

As the retrospective analysis of patient data shows, in HPV-negative head and neck tumors, a specific signalling pathway (the Hedgehog pathway) is often particularly active in the cancer cells, driving tumor growth. This activity can be indirectly detected in PET/CT images, for example through particularly strong uptake of a radioactive sugar molecule ([¹⁸F]FDG), which visualises the tumor's metabolism.

We were able to show that the images reveal how biologically aggressive a tumor is. This means that imaging can provide more information than just the size and location of the tumor or whether there are metastases."

Lukas Kenner, study leader

In further experiments, the research team tested what happens when the identified growth-promoting signalling pathway is specifically blocked. In cell cultures and animal models, this significantly slowed tumor growth. At the same time, the image signals in the PET/CT scans also changed. "This is particularly exciting because it means we are not only influencing the tumor, but can also see whether a treatment is working simply by looking at the modern imaging," explains lead author Stefan Stoiber.

The results suggest that PET/CT scans could in future help to better assess the progression of tumors and tailor therapies to individual patients. "Further studies are needed before this approach can be used in routine clinical practice. However, the work represents another important step towards personalized cancer therapy," says Lukas Kenner.