Unfortunately, this treatment can lead to varying degrees of cognitive and memory deficits months-to-years after treatment.
In fact, cognitive impairment is seen in as many as 60% of patients 4-months after treatment with whole-brain radiotherapy treatment.
Similar to other types of dementia, researchers have identified that radiation causes both vascular and neurodegenerative changes in the irradiated tissues of the brain.
Alzheimer’s drug research has led to the discovery of compounds that can slow down some of these degenerative changes.
One of these drugs is called, Memantine (trade name: Namenda), which has been shown to prevent the spread of vascular injury and prevent cognitive decline.
A promising randomized, double-blind, placebo-controlled study (RTOG 0614) has found that patients who are prescribed Memantine during (starting 3-days before) and after whole brain radiation therapy (for 6-months) had no decline in memory when assessed 6-months after radiation therapy (the patients taking the placebo had a significant decline in memory.)
Additionally, Memantine reduced cognitive dysfunction by 17% compared with placebo.
“Although memantine was discontinued at 6-months, the effect on cognitive function was maintained for the duration of the 12-month trial, suggesting that memantine may be preventing radiation injury rather than simply treating cognitive dysfunction.”
“The study demonstrates proof of principle that cognitive deterioration in brain metastasis patients can be prevented.”
The study authors recommend that memantine should “be offered—immediately—to brain metastasis patients.”
*This study was partially funded by the manufacturer of Memantine (Forest Pharmaceuticals)*
I currently prescribe Namenda for many of my patients who are undergoing radiation therapy to the brain. It is a drug with very few side effects, so I see little reason to wait for longer follow-up and larger clinical studies on this therapy before offering this patients. Of course, I explain to them that this study needs further confirmation in future trials, but it looks very promising. With that disclaimer, very few patients say they don’t want to be offered Namenda. If you or someone you know is about to undergo brain radiation therapy, discuss this therapy with the treating physicians.
Cognitive function drug proves beneficial for patients with brain cancer (Emory University, October 3, 2013)