New WBRT Technique Reduces Neurocognitive Decline Risk

Adverse cognition effects of whole- brain radiotherapy (WBRT) can be significantly mitigated by using a hippocampal sparing technique and a neuroprotective agent, claims a new study.

Researchers at Northwestern Medicine Cancer Center (Warrenville, IL, USA) conducted a study in 518 adult patients with brain metastases who were stratified by analysis of prognostic factors and by whether or not they had previously undergone radiosurgery or surgical resection. The patients were randomized to a combination of memantine (a low-affinity glutamatergic antagonist) and WBRT at a dose of 30 Gy in 10 fractions, or to memantine plus WBRT and hippocampal avoidance, again at a dose of 30 Gy in 10 fractions.

The results revealed that at six months, cognitive function failure rates were 59.5% in the hippocampal avoidance arm, compared 68.2% in the control arm, a 24% reduction. Cognitive function failure curves began to separate at three months, maintained through the follow-up period. Following adjustment for treatment factors and age, the additional use of hippocampal avoidance techniques led to a 26% relative risk reduction in cognitive failure compared with WBRT plus memantine, in all age groups. The study was presented at the American Society for Radiation Oncology (ASTRO) annual conference, held during October 2018 in San Antonio (TX, USA).

“Quality of life for patients with brain metastases can be largely driven by their cognitive function, and we've come to understand that WBRT can significantly impact that cognitive function outcome as well as the quality of life associated with it,” said lead author Vinai Gondi, MD. “Conformal avoidance of the hippocampal dentate gyrus using during WBRT plus memantine preserves cognitive function in patients with brain metastases with no difference in toxicity, intracranial progression-free survival rates, or overall survival.”

The hippocampus (named after its resemblance to the seahorse) is a major component of the brains of humans and other vertebrates. The hippocampus belongs to the limbic system and plays important roles in the consolidation of information from short-term, long-term, and spatial memory. It is located under the cerebral cortex, and contains two main interlocking parts: the hippocampus proper (also called Ammon's horn) and the dentate gyrus.

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