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Study Reveals Effects of Chemoradiation in Brains of Glioblastoma Patients

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Key Points

  • Whole-brain volume decreased significantly throughout the 35-week study period.
  • The reduced brain volume was seen mostly in grey matter.
  • The size of the brain's ventricles became progressively larger during the course of treatment, and changes were also seen within the subventricular zone.

A study from Massachusetts General Hospital (MGH) Cancer Center researchers—the first to examine the effects of combined radiation and chemotherapy on the healthy brain tissue of glioblastoma patients—revealed not only specific structural changes within patients’ brains, but also the effects of cancer therapy on the normal brain even after radiation therapy has ceased. The report was published by Prust et al in Neurology.

“It is well known that whole-brain radiation can have adverse, neurotoxic effects and causes loss of brain volume in some individuals,” said Jorg Dietrich, MD, PhD, of the Pappas Center for Neuro-Oncology at MGH. “This is the first prospective and longitudinal study to characterize structural brain changes resulting from standard radiation and chemotherapy in patients with malignant brain tumors. Further studies with neuropsychological evaluation will be needed to characterize the functional consequences of these structural changes.”

Study Findings

The study enrolled 14 glioblastoma patients who were scheduled to receive chemotherapy and radiation after surgical tumor removal. Before and during the 35-week standard treatment protocol—which was not altered for the current study—magnetic resonance images were taken with the high-power 3-Tesla scanner at the MGH-based Martinos Center for Biomedical Imaging.

In the eight participants for whom an adequate number of imaging studies were completed, whole-brain volume decreased significantly throughout the study period. The reduced volume was apparent within a few weeks after initiation of treatment and was primarily seen in grey matter. The size of the brain's ventricles became progressively larger during the course of treatment, and changes were also seen within the subventricular zone, one of two structures in which new brain cells are generated in adults.

“We were surprised to see that these changes—reduced grey matter volume and ventricular enlargement—occurred after just a few weeks of treatment, and continued to progress even after radiation therapy was completed. While this was a small study, these changes affected every patient [involved] at least to some degree,” said Dr. Dietrich.

“Now we need to investigate whether these structural changes correlate with reduced cognitive function, and whether neuroprotective strategies might be able to stop the progression of brain volume loss,” he continued. “Establishing novel imaging biomarkers of treatment-associated neurotoxicity—such as ventricular enlargement, which can be tracked with any magnetic resonance scanner—will be a critical step toward developing more selective therapies that are targeted to the tumor and spare normal brain tissue.”

Dr. Dietrich is the corresponding author for the Neurology article.

This study was supported by the National Cancer Institute and the American Cancer Society.

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.


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