PET/CT helps predict therapy effectiveness in paediatric brain tumours

In this first ever molecular drug-imaging study in children, researchers in The Netherlands used whole-body positron emission tomography/computed tomography (PET/CT) scans to determine whether bevacizumab (Avastin) treatment of diffuse intrinsic pontine glioma (DIPG) in children is likely to be effective.

“These tumours are resistant to all kinds of therapies. Chemotherapy, as well as new targeted therapies, may not reach the tumour due to the location within the brainstem.”

For the study, researchers investigated whether bevacizumab can reach the tumour in children with DIPG by measuring the tumour uptake of zirconium-89 (Zr-89)-labelled bevacizumab with PET.

In addition, they evaluated the safety of the procedure and determined the optimal timing of imaging.

PET/CT scans

Two weeks after completing radiotherapy, seven patients (age range: 6-17) were given whole-body PET/CT scans performed at 1, 72 and 144 hours post-injection. The optimal moment of scanning was found to be 144 hours post-injection. The patients also underwent contrast (gadolinium)-enhanced MRI.

“The results showed that indeed there is considerable heterogeneity in uptake of Zr-89-labeled bevacizumab among patients and within tumours,” Van Dongen points out.

Van Dongen adds, “Children with brain tumours and other solid cancers are particularly likely to benefit from molecular drug imaging, as drugs without therapeutic effect–based on a lack of drug-uptake in the tumour–may cause life-long side effects. Molecular drug imaging will open avenues for administering the right drug to the right patient at the most appropriate stage of the disease.”