Imaging Chemotherapy-Induced Brain Damage in Pediatric Cancer Survivors
Many pediatric cancer survivors face chronic and life-altering side effects as a result of their chemotherapy.
Children treated with high dose methotrexate (MTX) chemotherapy can experience neurocognitive decrements
that include impairments in memory, attention, and concentration. The overall cumulative incidence of
neurocognitive morbidities ranges from 25 to 45%. There is a window of time between the exposure to therapy
and future morbidity. Unfortunately, once cancer survivors present with clinical morbidities, it is often too late
for health-preserving interventions. To prevent drug-induced clinical problems after therapy, it is important to
develop diagnostic tools to detect the early stages of tissue damage that are still reversible. However, the
development of related biomarkers has gained surprisingly little attention in the field. To close this gap, we aim
to develop novel diagnostic biomarkers for detection of early tissue damage before clinical problems become
apparent. The obtained information could then be used to initiate corrective actions before long-term
morbidities occur and ultimately preserve the health of our patients. The overall goal of our project is to
detect early imaging signs of chemotherapy-induced brain damage that can predict chronic
neurocognitive problems months or years later. We are uniquely positioned to pursue this goal because we
can leverage an image registry, which contains serial positron emission tomography (PET) and magnetic
resonance imaging (MRI) scans of pediatric cancer patients before, during and after chemotherapy. Our
preliminary data showed that novel PET/MRI techniques, which enable simultaneous assessment of brain
morphology and metabolism, can detect and quantify physiological disturbances of the brain with high
sensitivity. Using this new imaging technology, we will measure brain volume, cortical thickness (T1 SPGR),
leukoencephalopathy (T2), brain perfusion (arterial spin labeling), and regional cerebral metabolic rate of
glucose metabolism (rCMRglc). We hypothesize that imaging biomarkers in the dorsolateral prefrontal
brain and cingulate gyrus, as measured with PET/MRI, will correlate with executive function scores,
assessed with neurocognitive function tests. Prediction and early detection of MTX-induced neurotoxicity
will allow us to identify patients who will benefit from early interventions, prescribe individual treatment regimes,
and ultimately prevent long-term morbidities.